API takes the dma-buf fd as input, and binds it to the netdevice. The user can specify the rx queues to bind the dma-buf to.

Suggested-by: Stanislav Fomichev sdf@fomichev.me Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Donald Hunter donald.hunter@gmail.com Reviewed-by: Jakub Kicinski kuba@kernel.org

---

v16: - Use subset-of: queue queue-id instead of queue-dmabuf (Jakub). - Rename attribute 'bind-dmabuf' to more generic 'dmabuf' (Jakub). - Use 'dmabuf' everywhere instead of mix of 'dma-buf' and 'dmabuf' (Donald). - Remove repetitive 'dmabuf' naming that appeared in some places (Jakub). - Reordered where the new operations went so I don't break the enum UAPI (Jakub).

v7: - Use flags: [ admin-perm ] instead of a CAP_NET_ADMIN check.

Changes in v1: - Add rx-queue-type to distingish rx from tx (Jakub) - Return dma-buf ID from netlink API (David, Stan)

Changes in RFC-v3: - Support binding multiple rx rx-queues

--- Documentation/netlink/specs/netdev.yaml | 47 +++++++++++++++++++++++++ include/uapi/linux/netdev.h | 11 ++++++ net/core/netdev-genl-gen.c | 19 ++++++++++ net/core/netdev-genl-gen.h | 2 ++ net/core/netdev-genl.c | 6 ++++ tools/include/uapi/linux/netdev.h | 11 ++++++ 6 files changed, 96 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml index 959755be4d7f..4930e8142aa6 100644 --- a/Documentation/netlink/specs/netdev.yaml +++ b/Documentation/netlink/specs/netdev.yaml @@ -457,6 +457,39 @@ attribute-sets: Number of times driver re-started accepting send requests to this queue from the stack. type: uint + - + name: queue-id + subset-of: queue + attributes: + - + name: id + - + name: type + - + name: dmabuf + attributes: + - + name: ifindex + doc: netdev ifindex to bind the dmabuf to. + type: u32 + checks: + min: 1 + - + name: queues + doc: receive queues to bind the dmabuf to. + type: nest + nested-attributes: queue-id + multi-attr: true + - + name: fd + doc: dmabuf file descriptor to bind. + type: u32 + - + name: id + doc: id of the dmabuf binding + type: u32 + checks: + min: 1

operations: list: @@ -619,6 +652,20 @@ operations: - rx-bytes - tx-packets - tx-bytes + - + name: bind-rx + doc: Bind dmabuf to netdev + attribute-set: dmabuf + flags: [ admin-perm ] + do: + request: + attributes: + - ifindex + - fd + - queues + reply: + attributes: + - id

mcast-groups: list: diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h index 43742ac5b00d..91bf3ecc5f1d 100644 --- a/include/uapi/linux/netdev.h +++ b/include/uapi/linux/netdev.h @@ -173,6 +173,16 @@ enum { NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1) };

+enum { + NETDEV_A_DMABUF_IFINDEX = 1, + NETDEV_A_DMABUF_QUEUES, + NETDEV_A_DMABUF_FD, + NETDEV_A_DMABUF_ID, + + __NETDEV_A_DMABUF_MAX, + NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1) +}; + enum { NETDEV_CMD_DEV_GET = 1, NETDEV_CMD_DEV_ADD_NTF, @@ -186,6 +196,7 @@ enum { NETDEV_CMD_QUEUE_GET, NETDEV_CMD_NAPI_GET, NETDEV_CMD_QSTATS_GET, + NETDEV_CMD_BIND_RX,

__NETDEV_CMD_MAX, NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1) diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c index 8350a0afa9ec..6b7fe6035067 100644 --- a/net/core/netdev-genl-gen.c +++ b/net/core/netdev-genl-gen.c @@ -27,6 +27,11 @@ const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFIND [NETDEV_A_PAGE_POOL_IFINDEX] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_page_pool_ifindex_range), };

+const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1] = { + [NETDEV_A_QUEUE_ID] = { .type = NLA_U32, }, + [NETDEV_A_QUEUE_TYPE] = NLA_POLICY_MAX(NLA_U32, 1), +}; + /* NETDEV_CMD_DEV_GET - do */ static const struct nla_policy netdev_dev_get_nl_policy[NETDEV_A_DEV_IFINDEX + 1] = { [NETDEV_A_DEV_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1), @@ -74,6 +79,13 @@ static const struct nla_policy netdev_qstats_get_nl_policy[NETDEV_A_QSTATS_SCOPE [NETDEV_A_QSTATS_SCOPE] = NLA_POLICY_MASK(NLA_UINT, 0x1), };

+/* NETDEV_CMD_BIND_RX - do */ +static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1] = { + [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1), + [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, }, + [NETDEV_A_DMABUF_QUEUES] = NLA_POLICY_NESTED(netdev_queue_id_nl_policy), +}; + /* Ops table for netdev */ static const struct genl_split_ops netdev_nl_ops[] = { { @@ -151,6 +163,13 @@ static const struct genl_split_ops netdev_nl_ops[] = { .maxattr = NETDEV_A_QSTATS_SCOPE, .flags = GENL_CMD_CAP_DUMP, }, + { + .cmd = NETDEV_CMD_BIND_RX, + .doit = netdev_nl_bind_rx_doit, + .policy = netdev_bind_rx_nl_policy, + .maxattr = NETDEV_A_DMABUF_FD, + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, + }, };

static const struct genl_multicast_group netdev_nl_mcgrps[] = { diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h index 4db40fd5b4a9..67c34005750c 100644 --- a/net/core/netdev-genl-gen.h +++ b/net/core/netdev-genl-gen.h @@ -13,6 +13,7 @@

/* Common nested types */ extern const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1]; +extern const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1];

int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info); int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); @@ -30,6 +31,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info); int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); +int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info);

enum { NETDEV_NLGRP_MGMT, diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c index 05f9515d2c05..2d726e65211d 100644 --- a/net/core/netdev-genl.c +++ b/net/core/netdev-genl.c @@ -721,6 +721,12 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, return err; }

+/* Stub */ +int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info) +{ + return 0; +} + static int netdev_genl_netdevice_event(struct notifier_block *nb, unsigned long event, void *ptr) { diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h index 43742ac5b00d..91bf3ecc5f1d 100644 --- a/tools/include/uapi/linux/netdev.h +++ b/tools/include/uapi/linux/netdev.h @@ -173,6 +173,16 @@ enum { NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1) };

+enum { + NETDEV_A_DMABUF_IFINDEX = 1, + NETDEV_A_DMABUF_QUEUES, + NETDEV_A_DMABUF_FD, + NETDEV_A_DMABUF_ID, + + __NETDEV_A_DMABUF_MAX, + NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1) +}; + enum { NETDEV_CMD_DEV_GET = 1, NETDEV_CMD_DEV_ADD_NTF, @@ -186,6 +196,7 @@ enum { NETDEV_CMD_QUEUE_GET, NETDEV_CMD_NAPI_GET, NETDEV_CMD_QSTATS_GET, + NETDEV_CMD_BIND_RX,

__NETDEV_CMD_MAX, NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1)

Convert netmem to be a union of struct page and struct netmem. Overload the LSB of struct netmem* to indicate that it's a net_iov, otherwise it's a page.

Currently these entries in struct page are rented by the page_pool and used exclusively by the net stack:

struct { unsigned long pp_magic; struct page_pool *pp; unsigned long _pp_mapping_pad; unsigned long dma_addr; atomic_long_t pp_ref_count; };

Mirror these (and only these) entries into struct net_iov and implement netmem helpers that can access these common fields regardless of whether the underlying type is page or net_iov.

Implement checks for net_iov in netmem helpers which delegate to mm APIs, to ensure net_iov are never passed to the mm stack.

Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Pavel Begunkov asml.silence@gmail.com Acked-by: Jakub Kicinski kuba@kernel.org

---

v23: - Fix comment on netmem_is_perf_nid (Jakub)

v19: - Move page_pool_set_dma_addr(_netmem) to page_pool_priv.h - Don't reset niov dma_addr on allocation/free. Instead, it's set once when the binding happens and it never changes (Jakub)

v17: - Rename netmem_to_pfn to netmem_pfn_trace (Jakub) - Move some low level netmem helpers to netmem_priv.h (Jakub).

v13: - Move NET_IOV dependent changes to this patch. - Fixed comment (Pavel) - Applied Reviewed-by from Pavel.

v9: https://lore.kernel.org/netdev/20240403002053.2376017-8-almasrymina@google.c... - Remove CONFIG checks in netmem_is_net_iov() (Pavel/David/Jens)

v7: - Remove static_branch_unlikely from netmem_to_net_iov(). We're getting better results from the fast path in bench_page_pool_simple tests without the static_branch_unlikely, and the addition of static_branch_unlikely doesn't improve performance of devmem TCP.

Additionally only check netmem_to_net_iov() if CONFIG_DMA_SHARED_BUFFER is enabled, otherwise dmabuf net_iovs cannot exist anyway.

net-next base: 8 cycle fast path. with static_branch_unlikely: 10 cycle fast path. without static_branch_unlikely: 9 cycle fast path. CONFIG_DMA_SHARED_BUFFER disabled: 8 cycle fast path as baseline.

Performance of devmem TCP is at 95% line rate is regardless of static_branch_unlikely or not.

v6: - Rebased on top of the merged netmem_ref type. - Rebased on top of the merged skb_pp_frag_ref() changes.

v5: - Use netmem instead of page* with LSB set. - Use pp_ref_count for refcounting net_iov. - Removed many of the custom checks for netmem.

v1: - Disable fragmentation support for iov properly. - fix napi_pp_put_page() path (Yunsheng). - Use pp_frag_count for devmem refcounting.

Cc: linux-mm@kvack.org Cc: Matthew Wilcox willy@infradead.org

--- include/net/netmem.h | 122 +++++++++++++++++++++++++++++-- include/net/page_pool/helpers.h | 39 ++-------- include/trace/events/page_pool.h | 12 +-- net/core/devmem.c | 8 ++ net/core/netmem_priv.h | 31 ++++++++ net/core/page_pool.c | 25 ++++--- net/core/page_pool_priv.h | 26 +++++++ net/core/skbuff.c | 23 +++--- 8 files changed, 217 insertions(+), 69 deletions(-) create mode 100644 net/core/netmem_priv.h

diff --git a/include/net/netmem.h b/include/net/netmem.h index 0fbc0999091a..ac6c7945117b 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -9,13 +9,51 @@ #define _NET_NETMEM_H

#include <net/devmem.h> +#include <net/net_debug.h>

/* net_iov */

+DECLARE_STATIC_KEY_FALSE(page_pool_mem_providers); + +/* We overload the LSB of the struct page pointer to indicate whether it's + * a page or net_iov. + */ +#define NET_IOV 0x01UL + struct net_iov { + unsigned long __unused_padding; + unsigned long pp_magic; + struct page_pool *pp; struct dmabuf_genpool_chunk_owner *owner; + unsigned long dma_addr; + atomic_long_t pp_ref_count; };

+/* These fields in struct page are used by the page_pool and net stack: + * + * struct { + * unsigned long pp_magic; + * struct page_pool *pp; + * unsigned long _pp_mapping_pad; + * unsigned long dma_addr; + * atomic_long_t pp_ref_count; + * }; + * + * We mirror the page_pool fields here so the page_pool can access these fields + * without worrying whether the underlying fields belong to a page or net_iov. + * + * The non-net stack fields of struct page are private to the mm stack and must + * never be mirrored to net_iov. + */ +#define NET_IOV_ASSERT_OFFSET(pg, iov) \ + static_assert(offsetof(struct page, pg) == \ + offsetof(struct net_iov, iov)) +NET_IOV_ASSERT_OFFSET(pp_magic, pp_magic); +NET_IOV_ASSERT_OFFSET(pp, pp); +NET_IOV_ASSERT_OFFSET(dma_addr, dma_addr); +NET_IOV_ASSERT_OFFSET(pp_ref_count, pp_ref_count); +#undef NET_IOV_ASSERT_OFFSET + static inline struct dmabuf_genpool_chunk_owner * net_iov_owner(const struct net_iov *niov) { @@ -46,20 +84,37 @@ net_iov_binding(const struct net_iov *niov) */ typedef unsigned long __bitwise netmem_ref;

+static inline bool netmem_is_net_iov(const netmem_ref netmem) +{ + return (__force unsigned long)netmem & NET_IOV; +} + /* This conversion fails (returns NULL) if the netmem_ref is not struct page * backed. - * - * Currently struct page is the only possible netmem, and this helper never - * fails. */ static inline struct page *netmem_to_page(netmem_ref netmem) { + if (WARN_ON_ONCE(netmem_is_net_iov(netmem))) + return NULL; + return (__force struct page *)netmem; }

-/* Converting from page to netmem is always safe, because a page can always be - * a netmem. - */ +static inline struct net_iov *netmem_to_net_iov(netmem_ref netmem) +{ + if (netmem_is_net_iov(netmem)) + return (struct net_iov *)((__force unsigned long)netmem & + ~NET_IOV); + + DEBUG_NET_WARN_ON_ONCE(true); + return NULL; +} + +static inline netmem_ref net_iov_to_netmem(struct net_iov *niov) +{ + return (__force netmem_ref)((unsigned long)niov | NET_IOV); +} + static inline netmem_ref page_to_netmem(struct page *page) { return (__force netmem_ref)page; @@ -67,17 +122,70 @@ static inline netmem_ref page_to_netmem(struct page *page)

static inline int netmem_ref_count(netmem_ref netmem) { + /* The non-pp refcount of net_iov is always 1. On net_iov, we only + * support pp refcounting which uses the pp_ref_count field. + */ + if (netmem_is_net_iov(netmem)) + return 1; + return page_ref_count(netmem_to_page(netmem)); }

-static inline unsigned long netmem_to_pfn(netmem_ref netmem) +static inline unsigned long netmem_pfn_trace(netmem_ref netmem) { + if (netmem_is_net_iov(netmem)) + return 0; + return page_to_pfn(netmem_to_page(netmem)); }

+static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem) +{ + return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV); +} + +static inline struct page_pool *netmem_get_pp(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->pp; +} + +static inline atomic_long_t *netmem_get_pp_ref_count_ref(netmem_ref netmem) +{ + return &__netmem_clear_lsb(netmem)->pp_ref_count; +} + +static inline bool netmem_is_pref_nid(netmem_ref netmem, int pref_nid) +{ + /* NUMA node preference only makes sense if we're allocating + * system memory. Memory providers (which give us net_iovs) + * choose for us. + */ + if (netmem_is_net_iov(netmem)) + return true; + + return page_to_nid(netmem_to_page(netmem)) == pref_nid; +} + static inline netmem_ref netmem_compound_head(netmem_ref netmem) { + /* niov are never compounded */ + if (netmem_is_net_iov(netmem)) + return netmem; + return page_to_netmem(compound_head(netmem_to_page(netmem))); }

+static inline void *netmem_address(netmem_ref netmem) +{ + if (netmem_is_net_iov(netmem)) + return NULL; + + return page_address(netmem_to_page(netmem)); +} + +static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->dma_addr; +} + #endif /* _NET_NETMEM_H */ diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 2b43a893c619..793e6fd78bc5 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -216,7 +216,7 @@ page_pool_get_dma_dir(const struct page_pool *pool)

static inline void page_pool_fragment_netmem(netmem_ref netmem, long nr) { - atomic_long_set(&netmem_to_page(netmem)->pp_ref_count, nr); + atomic_long_set(netmem_get_pp_ref_count_ref(netmem), nr); }

/** @@ -244,7 +244,7 @@ static inline void page_pool_fragment_page(struct page *page, long nr)

static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) { - struct page *page = netmem_to_page(netmem); + atomic_long_t *pp_ref_count = netmem_get_pp_ref_count_ref(netmem); long ret;

/* If nr == pp_ref_count then we have cleared all remaining @@ -261,19 +261,19 @@ static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) * initially, and only overwrite it when the page is partitioned into * more than one piece. */ - if (atomic_long_read(&page->pp_ref_count) == nr) { + if (atomic_long_read(pp_ref_count) == nr) { /* As we have ensured nr is always one for constant case using * the BUILD_BUG_ON(), only need to handle the non-constant case * here for pp_ref_count draining, which is a rare case. */ BUILD_BUG_ON(__builtin_constant_p(nr) && nr != 1); if (!__builtin_constant_p(nr)) - atomic_long_set(&page->pp_ref_count, 1); + atomic_long_set(pp_ref_count, 1);

return 0; }

- ret = atomic_long_sub_return(nr, &page->pp_ref_count); + ret = atomic_long_sub_return(nr, pp_ref_count); WARN_ON(ret < 0);

/* We are the last user here too, reset pp_ref_count back to 1 to @@ -282,7 +282,7 @@ static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) * page_pool_unref_page() currently. */ if (unlikely(!ret)) - atomic_long_set(&page->pp_ref_count, 1); + atomic_long_set(pp_ref_count, 1);

return ret; } @@ -401,9 +401,7 @@ static inline void page_pool_free_va(struct page_pool *pool, void *va,

static inline dma_addr_t page_pool_get_dma_addr_netmem(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - dma_addr_t ret = page->dma_addr; + dma_addr_t ret = netmem_get_dma_addr(netmem);

if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) ret <<= PAGE_SHIFT; @@ -423,24 +421,6 @@ static inline dma_addr_t page_pool_get_dma_addr(const struct page *page) return page_pool_get_dma_addr_netmem(page_to_netmem((struct page *)page)); }

-static inline bool page_pool_set_dma_addr_netmem(netmem_ref netmem, - dma_addr_t addr) -{ - struct page *page = netmem_to_page(netmem); - - if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) { - page->dma_addr = addr >> PAGE_SHIFT; - - /* We assume page alignment to shave off bottom bits, - * if this "compression" doesn't work we need to drop. - */ - return addr != (dma_addr_t)page->dma_addr << PAGE_SHIFT; - } - - page->dma_addr = addr; - return false; -} - /** * page_pool_dma_sync_for_cpu - sync Rx page for CPU after it's written by HW * @pool: &page_pool the @page belongs to @@ -463,11 +443,6 @@ static inline void page_pool_dma_sync_for_cpu(const struct page_pool *pool, page_pool_get_dma_dir(pool)); }

-static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) -{ - return page_pool_set_dma_addr_netmem(page_to_netmem(page), addr); -} - static inline bool page_pool_put(struct page_pool *pool) { return refcount_dec_and_test(&pool->user_cnt); diff --git a/include/trace/events/page_pool.h b/include/trace/events/page_pool.h index 543e54e432a1..31825ed30032 100644 --- a/include/trace/events/page_pool.h +++ b/include/trace/events/page_pool.h @@ -57,12 +57,12 @@ TRACE_EVENT(page_pool_state_release, __entry->pool = pool; __entry->netmem = (__force unsigned long)netmem; __entry->release = release; - __entry->pfn = netmem_to_pfn(netmem); + __entry->pfn = netmem_pfn_trace(netmem); ),

- TP_printk("page_pool=%p netmem=%p pfn=0x%lx release=%u", + TP_printk("page_pool=%p netmem=%p is_net_iov=%lu pfn=0x%lx release=%u", __entry->pool, (void *)__entry->netmem, - __entry->pfn, __entry->release) + __entry->netmem & NET_IOV, __entry->pfn, __entry->release) );

TRACE_EVENT(page_pool_state_hold, @@ -83,12 +83,12 @@ TRACE_EVENT(page_pool_state_hold, __entry->pool = pool; __entry->netmem = (__force unsigned long)netmem; __entry->hold = hold; - __entry->pfn = netmem_to_pfn(netmem); + __entry->pfn = netmem_pfn_trace(netmem); ),

- TP_printk("page_pool=%p netmem=%p pfn=0x%lx hold=%u", + TP_printk("page_pool=%p netmem=%p is_net_iov=%lu, pfn=0x%lx hold=%u", __entry->pool, (void *)__entry->netmem, - __entry->pfn, __entry->hold) + __entry->netmem & NET_IOV, __entry->pfn, __entry->hold) );

TRACE_EVENT(page_pool_update_nid, diff --git a/net/core/devmem.c b/net/core/devmem.c index ad222d108d37..727e5ee39f30 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -18,6 +18,8 @@ #include <net/page_pool/helpers.h> #include <trace/events/page_pool.h>

+#include "page_pool_priv.h" + /* Device memory support */

/* Protected by rtnl_lock() */ @@ -81,6 +83,10 @@ net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) index = offset / PAGE_SIZE; niov = &owner->niovs[index];

+ niov->pp_magic = 0; + niov->pp = NULL; + atomic_long_set(&niov->pp_ref_count, 0); + return niov; }

@@ -268,6 +274,8 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd, for (i = 0; i < owner->num_niovs; i++) { niov = &owner->niovs[i]; niov->owner = owner; + page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), + net_devmem_get_dma_addr(niov)); }

virtual += len; diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h new file mode 100644 index 000000000000..7eadb8393e00 --- /dev/null +++ b/net/core/netmem_priv.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __NETMEM_PRIV_H +#define __NETMEM_PRIV_H + +static inline unsigned long netmem_get_pp_magic(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->pp_magic; +} + +static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic) +{ + __netmem_clear_lsb(netmem)->pp_magic |= pp_magic; +} + +static inline void netmem_clear_pp_magic(netmem_ref netmem) +{ + __netmem_clear_lsb(netmem)->pp_magic = 0; +} + +static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool) +{ + __netmem_clear_lsb(netmem)->pp = pool; +} + +static inline void netmem_set_dma_addr(netmem_ref netmem, + unsigned long dma_addr) +{ + __netmem_clear_lsb(netmem)->dma_addr = dma_addr; +} +#endif diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 2abe6e919224..52659db2d765 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -24,8 +24,11 @@

#include <trace/events/page_pool.h>

+#include "netmem_priv.h" #include "page_pool_priv.h"

+DEFINE_STATIC_KEY_FALSE(page_pool_mem_providers); + #define DEFER_TIME (msecs_to_jiffies(1000)) #define DEFER_WARN_INTERVAL (60 * HZ)

@@ -358,7 +361,7 @@ static noinline netmem_ref page_pool_refill_alloc_cache(struct page_pool *pool) if (unlikely(!netmem)) break;

- if (likely(page_to_nid(netmem_to_page(netmem)) == pref_nid)) { + if (likely(netmem_is_pref_nid(netmem, pref_nid))) { pool->alloc.cache[pool->alloc.count++] = netmem; } else { /* NUMA mismatch; @@ -454,10 +457,8 @@ static bool page_pool_dma_map(struct page_pool *pool, netmem_ref netmem)

static void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page->pp = pool; - page->pp_magic |= PP_SIGNATURE; + netmem_set_pp(netmem, pool); + netmem_or_pp_magic(netmem, PP_SIGNATURE);

/* Ensuring all pages have been split into one fragment initially: * page_pool_set_pp_info() is only called once for every page when it @@ -472,10 +473,8 @@ static void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem)

static void page_pool_clear_pp_info(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page->pp_magic = 0; - page->pp = NULL; + netmem_clear_pp_magic(netmem); + netmem_set_pp(netmem, NULL); }

static struct page *__page_pool_alloc_page_order(struct page_pool *pool, @@ -692,8 +691,9 @@ static bool page_pool_recycle_in_cache(netmem_ref netmem,

static bool __page_pool_page_can_be_recycled(netmem_ref netmem) { - return page_ref_count(netmem_to_page(netmem)) == 1 && - !page_is_pfmemalloc(netmem_to_page(netmem)); + return netmem_is_net_iov(netmem) || + (page_ref_count(netmem_to_page(netmem)) == 1 && + !page_is_pfmemalloc(netmem_to_page(netmem))); }

/* If the page refcnt == 1, this will try to recycle the page. @@ -728,6 +728,7 @@ __page_pool_put_page(struct page_pool *pool, netmem_ref netmem, /* Page found as candidate for recycling */ return netmem; } + /* Fallback/non-XDP mode: API user have elevated refcnt. * * Many drivers split up the page into fragments, and some @@ -949,7 +950,7 @@ static void page_pool_empty_ring(struct page_pool *pool) /* Empty recycle ring */ while ((netmem = (__force netmem_ref)ptr_ring_consume_bh(&pool->ring))) { /* Verify the refcnt invariant of cached pages */ - if (!(page_ref_count(netmem_to_page(netmem)) == 1)) + if (!(netmem_ref_count(netmem) == 1)) pr_crit("%s() page_pool refcnt %d violation\n", __func__, netmem_ref_count(netmem));

diff --git a/net/core/page_pool_priv.h b/net/core/page_pool_priv.h index 90665d40f1eb..2142caeddb7c 100644 --- a/net/core/page_pool_priv.h +++ b/net/core/page_pool_priv.h @@ -3,10 +3,36 @@ #ifndef __PAGE_POOL_PRIV_H #define __PAGE_POOL_PRIV_H

+#include <net/page_pool/helpers.h> + +#include "netmem_priv.h" + s32 page_pool_inflight(const struct page_pool *pool, bool strict);

int page_pool_list(struct page_pool *pool); void page_pool_detached(struct page_pool *pool); void page_pool_unlist(struct page_pool *pool);

+static inline bool page_pool_set_dma_addr_netmem(netmem_ref netmem, + dma_addr_t addr) +{ + if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) { + netmem_set_dma_addr(netmem, addr >> PAGE_SHIFT); + + /* We assume page alignment to shave off bottom bits, + * if this "compression" doesn't work we need to drop. + */ + return addr != (dma_addr_t)netmem_get_dma_addr(netmem) + << PAGE_SHIFT; + } + + netmem_set_dma_addr(netmem, addr); + return false; +} + +static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) +{ + return page_pool_set_dma_addr_netmem(page_to_netmem(page), addr); +} + #endif diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a52638363ea5..d9634ab342cc 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -88,6 +88,7 @@ #include <linux/textsearch.h>

#include "dev.h" +#include "netmem_priv.h" #include "sock_destructor.h"

#ifdef CONFIG_SKB_EXTENSIONS @@ -920,9 +921,9 @@ static void skb_clone_fraglist(struct sk_buff *skb) skb_get(list); }

-static bool is_pp_page(struct page *page) +static bool is_pp_netmem(netmem_ref netmem) { - return (page->pp_magic & ~0x3UL) == PP_SIGNATURE; + return (netmem_get_pp_magic(netmem) & ~0x3UL) == PP_SIGNATURE; }

int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, @@ -1020,9 +1021,7 @@ EXPORT_SYMBOL(skb_cow_data_for_xdp); #if IS_ENABLED(CONFIG_PAGE_POOL) bool napi_pp_put_page(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page = compound_head(page); + netmem = netmem_compound_head(netmem);

/* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation * in order to preserve any existing bits, such as bit 0 for the @@ -1031,10 +1030,10 @@ bool napi_pp_put_page(netmem_ref netmem) * and page_is_pfmemalloc() is checked in __page_pool_put_page() * to avoid recycling the pfmemalloc page. */ - if (unlikely(!is_pp_page(page))) + if (unlikely(!is_pp_netmem(netmem))) return false;

- page_pool_put_full_netmem(page->pp, page_to_netmem(page), false); + page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, false);

return true; } @@ -1061,7 +1060,7 @@ static bool skb_pp_recycle(struct sk_buff *skb, void *data) static int skb_pp_frag_ref(struct sk_buff *skb) { struct skb_shared_info *shinfo; - struct page *head_page; + netmem_ref head_netmem; int i;

if (!skb->pp_recycle) @@ -1070,11 +1069,11 @@ static int skb_pp_frag_ref(struct sk_buff *skb) shinfo = skb_shinfo(skb);

for (i = 0; i < shinfo->nr_frags; i++) { - head_page = compound_head(skb_frag_page(&shinfo->frags[i])); - if (likely(is_pp_page(head_page))) - page_pool_ref_page(head_page); + head_netmem = netmem_compound_head(shinfo->frags[i].netmem); + if (likely(is_pp_netmem(head_netmem))) + page_pool_ref_netmem(head_netmem); else - page_ref_inc(head_page); + page_ref_inc(netmem_to_page(head_netmem)); } return 0; }

Make skb_frag_page() fail in the case where the frag is not backed by a page, and fix its relevant callers to handle this case.

Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Eric Dumazet edumazet@google.com

---

v10: - Fixed newly generated kdoc warnings found by patchwork. While we're at it, fix the Return section of the functions I touched.

v6: - Rebased on top of the merged netmem changes.

Changes in v1: - Fix illegal_highdma() (Yunsheng). - Rework napi_pp_put_page() slightly to reduce code churn (Willem).

--- include/linux/skbuff.h | 42 +++++++++++++++++++++++++++++++++++++- include/linux/skbuff_ref.h | 9 ++++---- net/core/dev.c | 3 ++- net/core/gro.c | 3 ++- net/core/skbuff.c | 11 ++++++++++ net/ipv4/esp4.c | 3 ++- net/ipv4/tcp.c | 3 +++ net/ipv6/esp6.c | 3 ++- 8 files changed, 67 insertions(+), 10 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index cf8f6ce06742..dbadf2dd6b35 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3523,21 +3523,58 @@ static inline void skb_frag_off_copy(skb_frag_t *fragto, fragto->offset = fragfrom->offset; }

+/* Return: true if the skb_frag contains a net_iov. */ +static inline bool skb_frag_is_net_iov(const skb_frag_t *frag) +{ + return netmem_is_net_iov(frag->netmem); +} + +/** + * skb_frag_net_iov - retrieve the net_iov referred to by fragment + * @frag: the fragment + * + * Return: the &struct net_iov associated with @frag. Returns NULL if this + * frag has no associated net_iov. + */ +static inline struct net_iov *skb_frag_net_iov(const skb_frag_t *frag) +{ + if (!skb_frag_is_net_iov(frag)) + return NULL; + + return netmem_to_net_iov(frag->netmem); +} + /** * skb_frag_page - retrieve the page referred to by a paged fragment * @frag: the paged fragment * - * Returns the &struct page associated with @frag. + * Return: the &struct page associated with @frag. Returns NULL if this frag + * has no associated page. */ static inline struct page *skb_frag_page(const skb_frag_t *frag) { + if (skb_frag_is_net_iov(frag)) + return NULL; + return netmem_to_page(frag->netmem); }

+/** + * skb_frag_netmem - retrieve the netmem referred to by a fragment + * @frag: the fragment + * + * Return: the &netmem_ref associated with @frag. + */ +static inline netmem_ref skb_frag_netmem(const skb_frag_t *frag) +{ + return frag->netmem; +} + int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, unsigned int headroom); int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb, struct bpf_prog *prog); + /** * skb_frag_address - gets the address of the data contained in a paged fragment * @frag: the paged fragment buffer @@ -3547,6 +3584,9 @@ int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb, */ static inline void *skb_frag_address(const skb_frag_t *frag) { + if (!skb_frag_page(frag)) + return NULL; + return page_address(skb_frag_page(frag)) + skb_frag_off(frag); }

diff --git a/include/linux/skbuff_ref.h b/include/linux/skbuff_ref.h index 16c241a23472..0f3c58007488 100644 --- a/include/linux/skbuff_ref.h +++ b/include/linux/skbuff_ref.h @@ -34,14 +34,13 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f)

bool napi_pp_put_page(netmem_ref netmem);

-static inline void -skb_page_unref(struct page *page, bool recycle) +static inline void skb_page_unref(netmem_ref netmem, bool recycle) { #ifdef CONFIG_PAGE_POOL - if (recycle && napi_pp_put_page(page_to_netmem(page))) + if (recycle && napi_pp_put_page(netmem)) return; #endif - put_page(page); + put_page(netmem_to_page(netmem)); }

/** @@ -54,7 +53,7 @@ skb_page_unref(struct page *page, bool recycle) */ static inline void __skb_frag_unref(skb_frag_t *frag, bool recycle) { - skb_page_unref(skb_frag_page(frag), recycle); + skb_page_unref(skb_frag_netmem(frag), recycle); }

/** diff --git a/net/core/dev.c b/net/core/dev.c index 5224d7c7177e..3b2ff2b91117 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3433,8 +3433,9 @@ static int illegal_highdma(struct net_device *dev, struct sk_buff *skb) if (!(dev->features & NETIF_F_HIGHDMA)) { for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + struct page *page = skb_frag_page(frag);

- if (PageHighMem(skb_frag_page(frag))) + if (page && PageHighMem(page)) return 1; } } diff --git a/net/core/gro.c b/net/core/gro.c index 3abad1b567dd..802b4a062400 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -408,7 +408,8 @@ static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) pinfo = skb_shinfo(skb); frag0 = &pinfo->frags[0];

- if (pinfo->nr_frags && !PageHighMem(skb_frag_page(frag0)) && + if (pinfo->nr_frags && skb_frag_page(frag0) && + !PageHighMem(skb_frag_page(frag0)) && (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index d9634ab342cc..7ea1508a1176 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1371,6 +1371,14 @@ void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt) struct page *p; u8 *vaddr;

+ if (skb_frag_is_net_iov(frag)) { + printk("%sskb frag %d: not readable\n", level, i); + len -= skb_frag_size(frag); + if (!len) + break; + continue; + } + skb_frag_foreach_page(frag, skb_frag_off(frag), skb_frag_size(frag), p, p_off, p_len, copied) { @@ -3163,6 +3171,9 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];

+ if (WARN_ON_ONCE(!skb_frag_page(f))) + return false; + if (__splice_segment(skb_frag_page(f), skb_frag_off(f), skb_frag_size(f), offset, len, spd, false, sk, pipe)) diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c index 47378ca41904..f3281312eb5e 100644 --- a/net/ipv4/esp4.c +++ b/net/ipv4/esp4.c @@ -115,7 +115,8 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) */ if (req->src != req->dst) for (sg = sg_next(req->src); sg; sg = sg_next(sg)) - skb_page_unref(sg_page(sg), skb->pp_recycle); + skb_page_unref(page_to_netmem(sg_page(sg)), + skb->pp_recycle); }

#ifdef CONFIG_INET_ESPINTCP diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 8a5680b4e786..05844a36ffeb 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2177,6 +2177,9 @@ static int tcp_zerocopy_receive(struct sock *sk, break; } page = skb_frag_page(frags); + if (WARN_ON_ONCE(!page)) + break; + prefetchw(page); pages[pages_to_map++] = page; length += PAGE_SIZE; diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c index 3920e8aa1031..b2400c226a32 100644 --- a/net/ipv6/esp6.c +++ b/net/ipv6/esp6.c @@ -132,7 +132,8 @@ static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) */ if (req->src != req->dst) for (sg = sg_next(req->src); sg; sg = sg_next(sg)) - skb_page_unref(sg_page(sg), skb->pp_recycle); + skb_page_unref(page_to_netmem(sg_page(sg)), + skb->pp_recycle); }

#ifdef CONFIG_INET6_ESPINTCP

For device memory TCP, we expect the skb headers to be available in host memory for access, and we expect the skb frags to be in device memory and unaccessible to the host. We expect there to be no mixing and matching of device memory frags (unaccessible) with host memory frags (accessible) in the same skb.

Add a skb->devmem flag which indicates whether the frags in this skb are device memory frags or not.

__skb_fill_netmem_desc() now checks frags added to skbs for net_iov, and marks the skb as skb->devmem accordingly.

Add checks through the network stack to avoid accessing the frags of devmem skbs and avoid coalescing devmem skbs with non devmem skbs.

Signed-off-by: Willem de Bruijn willemb@google.com Signed-off-by: Kaiyuan Zhang kaiyuanz@google.com Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Eric Dumazet edumazet@google.com

---

v16: - Fix unreadable handling in skb_split_no_header() (Eric).

v11: - drop excessive checks for frag 0 pull (Paolo)

v9: https://lore.kernel.org/netdev/20240403002053.2376017-11-almasrymina@google.... - change skb->readable to skb->unreadable (Pavel/David).

skb->readable was very complicated, because by default skbs are readable so the flag needed to be set to true in all code paths where new skbs were created or cloned. Forgetting to set skb->readable=true in some paths caused crashes.

Flip it to skb->unreadable so that the default 0 value works well, and we only need to set it to true when we add unreadable frags.

v6 - skb->dmabuf -> skb->readable (Pavel). Pavel's original suggestion was to remove the skb->dmabuf flag entirely, but when I looked into it closely, I found the issue that if we remove the flag we have to dereference the shinfo(skb) pointer to obtain the first frag, which can cause a performance regression if it dirties the cache line when the shinfo(skb) was not really needed. Instead, I converted the skb->dmabuf flag into a generic skb->readable flag which can be re-used by io_uring.

Changes in v1: - Rename devmem -> dmabuf (David). - Flip skb_frags_not_readable (Jakub).

--- include/linux/skbuff.h | 19 +++++++++++++++++-- include/net/tcp.h | 5 +++-- net/core/datagram.c | 6 ++++++ net/core/skbuff.c | 43 ++++++++++++++++++++++++++++++++++++++++-- net/ipv4/tcp.c | 3 +++ net/ipv4/tcp_input.c | 13 ++++++++++--- net/ipv4/tcp_output.c | 5 ++++- net/packet/af_packet.c | 4 ++-- 8 files changed, 86 insertions(+), 12 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index dbadf2dd6b35..d02a88bad953 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -827,6 +827,8 @@ enum skb_tstamp_type { * @csum_level: indicates the number of consecutive checksums found in * the packet minus one that have been verified as * CHECKSUM_UNNECESSARY (max 3) + * @unreadable: indicates that at least 1 of the fragments in this skb is + * unreadable. * @dst_pending_confirm: need to confirm neighbour * @decrypted: Decrypted SKB * @slow_gro: state present at GRO time, slower prepare step required @@ -1008,7 +1010,7 @@ struct sk_buff { #if IS_ENABLED(CONFIG_IP_SCTP) __u8 csum_not_inet:1; #endif - + __u8 unreadable:1; #if defined(CONFIG_NET_SCHED) || defined(CONFIG_NET_XGRESS) __u16 tc_index; /* traffic control index */ #endif @@ -1823,6 +1825,12 @@ static inline void skb_zcopy_downgrade_managed(struct sk_buff *skb) __skb_zcopy_downgrade_managed(skb); }

+/* Return true if frags in this skb are readable by the host. */ +static inline bool skb_frags_readable(const struct sk_buff *skb) +{ + return !skb->unreadable; +} + static inline void skb_mark_not_on_list(struct sk_buff *skb) { skb->next = NULL; @@ -2539,10 +2547,17 @@ static inline void skb_len_add(struct sk_buff *skb, int delta) static inline void __skb_fill_netmem_desc(struct sk_buff *skb, int i, netmem_ref netmem, int off, int size) { - struct page *page = netmem_to_page(netmem); + struct page *page;

__skb_fill_netmem_desc_noacc(skb_shinfo(skb), i, netmem, off, size);

+ if (netmem_is_net_iov(netmem)) { + skb->unreadable = true; + return; + } + + page = netmem_to_page(netmem); + /* Propagate page pfmemalloc to the skb if we can. The problem is * that not all callers have unique ownership of the page but rely * on page_is_pfmemalloc doing the right thing(tm). diff --git a/include/net/tcp.h b/include/net/tcp.h index 2aac11e7e1cc..e8f6e602c2ad 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1060,7 +1060,7 @@ static inline int tcp_skb_mss(const struct sk_buff *skb)

static inline bool tcp_skb_can_collapse_to(const struct sk_buff *skb) { - return likely(!TCP_SKB_CB(skb)->eor); + return likely(!TCP_SKB_CB(skb)->eor && skb_frags_readable(skb)); }

static inline bool tcp_skb_can_collapse(const struct sk_buff *to, @@ -1069,7 +1069,8 @@ static inline bool tcp_skb_can_collapse(const struct sk_buff *to, /* skb_cmp_decrypted() not needed, use tcp_write_collapse_fence() */ return likely(tcp_skb_can_collapse_to(to) && mptcp_skb_can_collapse(to, from) && - skb_pure_zcopy_same(to, from)); + skb_pure_zcopy_same(to, from) && + skb_frags_readable(to) == skb_frags_readable(from)); }

static inline bool tcp_skb_can_collapse_rx(const struct sk_buff *to, diff --git a/net/core/datagram.c b/net/core/datagram.c index a40f733b37d7..f0693707aece 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -407,6 +407,9 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset, return 0; }

+ if (!skb_frags_readable(skb)) + goto short_copy; + /* Copy paged appendix. Hmm... why does this look so complicated? */ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { int end; @@ -623,6 +626,9 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb, { int frag = skb_shinfo(skb)->nr_frags;

+ if (!skb_frags_readable(skb)) + return -EFAULT; + while (length && iov_iter_count(from)) { struct page *head, *last_head = NULL; struct page *pages[MAX_SKB_FRAGS]; diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 7ea1508a1176..40e1ce99d635 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1972,6 +1972,9 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) if (skb_shared(skb) || skb_unclone(skb, gfp_mask)) return -EINVAL;

+ if (!skb_frags_readable(skb)) + return -EFAULT; + if (!num_frags) goto release;

@@ -2145,6 +2148,9 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask) unsigned int size; int headerlen;

+ if (!skb_frags_readable(skb)) + return NULL; + if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST)) return NULL;

@@ -2483,6 +2489,9 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb, struct sk_buff *n; int oldheadroom;

+ if (!skb_frags_readable(skb)) + return NULL; + if (WARN_ON_ONCE(skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST)) return NULL;

@@ -2827,6 +2836,9 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) */ int i, k, eat = (skb->tail + delta) - skb->end;

+ if (!skb_frags_readable(skb)) + return NULL; + if (eat > 0 || skb_cloned(skb)) { if (pskb_expand_head(skb, 0, eat > 0 ? eat + 128 : 0, GFP_ATOMIC)) @@ -2980,6 +2992,9 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len) to += copy; }

+ if (!skb_frags_readable(skb)) + goto fault; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { int end; skb_frag_t *f = &skb_shinfo(skb)->frags[i]; @@ -3168,6 +3183,9 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe, /* * then map the fragments */ + if (!skb_frags_readable(skb)) + return false; + for (seg = 0; seg < skb_shinfo(skb)->nr_frags; seg++) { const skb_frag_t *f = &skb_shinfo(skb)->frags[seg];

@@ -3391,6 +3409,9 @@ int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len) from += copy; }

+ if (!skb_frags_readable(skb)) + goto fault; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; int end; @@ -3470,6 +3491,9 @@ __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, pos = copy; }

+ if (!skb_frags_readable(skb)) + return 0; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { int end; skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; @@ -3570,6 +3594,9 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, pos = copy; }

+ if (!skb_frags_readable(skb)) + return 0; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { int end;

@@ -4061,6 +4088,7 @@ static inline void skb_split_inside_header(struct sk_buff *skb, skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];

skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags; + skb1->unreadable = skb->unreadable; skb_shinfo(skb)->nr_frags = 0; skb1->data_len = skb->data_len; skb1->len += skb1->data_len; @@ -4108,6 +4136,8 @@ static inline void skb_split_no_header(struct sk_buff *skb, pos += size; } skb_shinfo(skb1)->nr_frags = k; + + skb1->unreadable = skb->unreadable; }

/** @@ -4345,6 +4375,9 @@ unsigned int skb_seq_read(unsigned int consumed, const u8 **data, return block_limit - abs_offset; }

+ if (!skb_frags_readable(st->cur_skb)) + return 0; + if (st->frag_idx == 0 && !st->frag_data) st->stepped_offset += skb_headlen(st->cur_skb);

@@ -5957,7 +5990,10 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, if (to->pp_recycle != from->pp_recycle) return false;

- if (len <= skb_tailroom(to)) { + if (skb_frags_readable(from) != skb_frags_readable(to)) + return false; + + if (len <= skb_tailroom(to) && skb_frags_readable(from)) { if (len) BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len)); *delta_truesize = 0; @@ -6134,6 +6170,9 @@ int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len) if (!pskb_may_pull(skb, write_len)) return -ENOMEM;

+ if (!skb_frags_readable(skb)) + return -EFAULT; + if (!skb_cloned(skb) || skb_clone_writable(skb, write_len)) return 0;

@@ -6813,7 +6852,7 @@ void skb_condense(struct sk_buff *skb) { if (skb->data_len) { if (skb->data_len > skb->end - skb->tail || - skb_cloned(skb)) + skb_cloned(skb) || !skb_frags_readable(skb)) return;

/* Nice, we can free page frag(s) right now */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 05844a36ffeb..30238963fe99 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2160,6 +2160,9 @@ static int tcp_zerocopy_receive(struct sock *sk, skb = tcp_recv_skb(sk, seq, &offset); }

+ if (!skb_frags_readable(skb)) + break; + if (TCP_SKB_CB(skb)->has_rxtstamp) { tcp_update_recv_tstamps(skb, tss); zc->msg_flags |= TCP_CMSG_TS; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index e37488d3453f..9f314dfa1490 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5391,6 +5391,9 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, for (end_of_skbs = true; skb != NULL && skb != tail; skb = n) { n = tcp_skb_next(skb, list);

+ if (!skb_frags_readable(skb)) + goto skip_this; + /* No new bits? It is possible on ofo queue. */ if (!before(start, TCP_SKB_CB(skb)->end_seq)) { skb = tcp_collapse_one(sk, skb, list, root); @@ -5411,17 +5414,20 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, break; }

- if (n && n != tail && tcp_skb_can_collapse_rx(skb, n) && + if (n && n != tail && skb_frags_readable(n) && + tcp_skb_can_collapse_rx(skb, n) && TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(n)->seq) { end_of_skbs = false; break; }

+skip_this: /* Decided to skip this, advance start seq. */ start = TCP_SKB_CB(skb)->end_seq; } if (end_of_skbs || - (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN))) + (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)) || + !skb_frags_readable(skb)) return;

__skb_queue_head_init(&tmp); @@ -5463,7 +5469,8 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list, struct rb_root *root, if (!skb || skb == tail || !tcp_skb_can_collapse_rx(nskb, skb) || - (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN))) + (TCP_SKB_CB(skb)->tcp_flags & (TCPHDR_SYN | TCPHDR_FIN)) || + !skb_frags_readable(skb)) goto end; } } diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index cdd0def14427..4fd746bd4d54 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2344,7 +2344,8 @@ static bool tcp_can_coalesce_send_queue_head(struct sock *sk, int len)

if (unlikely(TCP_SKB_CB(skb)->eor) || tcp_has_tx_tstamp(skb) || - !skb_pure_zcopy_same(skb, next)) + !skb_pure_zcopy_same(skb, next) || + skb_frags_readable(skb) != skb_frags_readable(next)) return false;

len -= skb->len; @@ -3264,6 +3265,8 @@ static bool tcp_can_collapse(const struct sock *sk, const struct sk_buff *skb) return false; if (skb_cloned(skb)) return false; + if (!skb_frags_readable(skb)) + return false; /* Some heuristics for collapsing over SACK'd could be invented */ if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) return false; diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 4a364cdd445e..a705ec214254 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2216,7 +2216,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, } }

- snaplen = skb->len; + snaplen = skb_frags_readable(skb) ? skb->len : skb_headlen(skb);

res = run_filter(skb, sk, snaplen); if (!res) @@ -2336,7 +2336,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, } }

- snaplen = skb->len; + snaplen = skb_frags_readable(skb) ? skb->len : skb_headlen(skb);

res = run_filter(skb, sk, snaplen); if (!res)

In tcp_recvmsg_locked(), detect if the skb being received by the user is a devmem skb. In this case - if the user provided the MSG_SOCK_DEVMEM flag - pass it to tcp_recvmsg_devmem() for custom handling.

tcp_recvmsg_devmem() copies any data in the skb header to the linear buffer, and returns a cmsg to the user indicating the number of bytes returned in the linear buffer.

tcp_recvmsg_devmem() then loops over the unaccessible devmem skb frags, and returns to the user a cmsg_devmem indicating the location of the data in the dmabuf device memory. cmsg_devmem contains this information:

1. the offset into the dmabuf where the payload starts. 'frag_offset'. 2. the size of the frag. 'frag_size'. 3. an opaque token 'frag_token' to return to the kernel when the buffer is to be released.

The pages awaiting freeing are stored in the newly added sk->sk_user_frags, and each page passed to userspace is get_page()'d. This reference is dropped once the userspace indicates that it is done reading this page. All pages are released when the socket is destroyed.

Signed-off-by: Willem de Bruijn willemb@google.com Signed-off-by: Kaiyuan Zhang kaiyuanz@google.com Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Pavel Begunkov asml.silence@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com

---

v20: - Change `offset = 0` to `offset = offset - start` to resolve issue reported by Taehee.

v16: - Fix number assignement (Arnd).

v13: - Refactored user frags cleanup into a common function to avoid __maybe_unused. (Pavel) - change to offset = 0 for some improved clarity.

v11: - Refactor to common function te remove conditional lock sparse warning (Paolo)

v7: - Updated the SO_DEVMEM_* uapi to use the next available entries (Arnd). - Updated dmabuf_cmsg struct to be __u64 padded (Arnd). - Squashed fix from Eric to initialize sk_user_frags for passive sockets (Eric).

v6 - skb->dmabuf -> skb->readable (Pavel) - Fixed asm definitions of SO_DEVMEM_LINEAR/SO_DEVMEM_DMABUF not found on some archs. - Squashed in locking optimizations from edumazet@google.com. With this change we lock the xarray once per per tcp_recvmsg_dmabuf() rather than once per frag in xa_alloc().

Changes in v1: - Added dmabuf_id to dmabuf_cmsg (David/Stan). - Devmem -> dmabuf (David). - Change tcp_recvmsg_dmabuf() check to skb->dmabuf (Paolo). - Use __skb_frag_ref() & napi_pp_put_page() for refcounting (Yunsheng).

RFC v3: - Fixed issue with put_cmsg() failing silently.

--- arch/alpha/include/uapi/asm/socket.h | 5 + arch/mips/include/uapi/asm/socket.h | 5 + arch/parisc/include/uapi/asm/socket.h | 5 + arch/sparc/include/uapi/asm/socket.h | 5 + include/linux/socket.h | 1 + include/net/netmem.h | 13 ++ include/net/sock.h | 2 + include/uapi/asm-generic/socket.h | 5 + include/uapi/linux/uio.h | 13 ++ net/ipv4/tcp.c | 255 +++++++++++++++++++++++++- net/ipv4/tcp_ipv4.c | 16 ++ net/ipv4/tcp_minisocks.c | 2 + 12 files changed, 322 insertions(+), 5 deletions(-)

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h index e94f621903fe..ef4656a41058 100644 --- a/arch/alpha/include/uapi/asm/socket.h +++ b/arch/alpha/include/uapi/asm/socket.h @@ -140,6 +140,11 @@ #define SO_PASSPIDFD 76 #define SO_PEERPIDFD 77

+#define SO_DEVMEM_LINEAR 78 +#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR +#define SO_DEVMEM_DMABUF 79 +#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF + #if !defined(__KERNEL__)

#if __BITS_PER_LONG == 64 diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h index 60ebaed28a4c..414807d55e33 100644 --- a/arch/mips/include/uapi/asm/socket.h +++ b/arch/mips/include/uapi/asm/socket.h @@ -151,6 +151,11 @@ #define SO_PASSPIDFD 76 #define SO_PEERPIDFD 77

+#define SO_DEVMEM_LINEAR 78 +#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR +#define SO_DEVMEM_DMABUF 79 +#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF + #if !defined(__KERNEL__)

#if __BITS_PER_LONG == 64 diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h index be264c2b1a11..2b817efd4544 100644 --- a/arch/parisc/include/uapi/asm/socket.h +++ b/arch/parisc/include/uapi/asm/socket.h @@ -132,6 +132,11 @@ #define SO_PASSPIDFD 0x404A #define SO_PEERPIDFD 0x404B

+#define SO_DEVMEM_LINEAR 78 +#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR +#define SO_DEVMEM_DMABUF 79 +#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF + #if !defined(__KERNEL__)

#if __BITS_PER_LONG == 64 diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h index 682da3714686..00248fc68977 100644 --- a/arch/sparc/include/uapi/asm/socket.h +++ b/arch/sparc/include/uapi/asm/socket.h @@ -133,6 +133,11 @@ #define SO_PASSPIDFD 0x0055 #define SO_PEERPIDFD 0x0056

+#define SO_DEVMEM_LINEAR 0x0057 +#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR +#define SO_DEVMEM_DMABUF 0x0058 +#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF + #if !defined(__KERNEL__)

diff --git a/include/linux/socket.h b/include/linux/socket.h index df9cdb8bbfb8..d18cc47e89bd 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -327,6 +327,7 @@ struct ucred { * plain text and require encryption */

+#define MSG_SOCK_DEVMEM 0x2000000 /* Receive devmem skbs as cmsg */ #define MSG_ZEROCOPY 0x4000000 /* Use user data in kernel path */ #define MSG_SPLICE_PAGES 0x8000000 /* Splice the pages from the iterator in sendmsg() */ #define MSG_FASTOPEN 0x20000000 /* Send data in TCP SYN */ diff --git a/include/net/netmem.h b/include/net/netmem.h index 61400d4b0d66..209013aaea18 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -66,6 +66,19 @@ static inline unsigned int net_iov_idx(const struct net_iov *niov) return niov - net_iov_owner(niov)->niovs; }

+static inline unsigned long net_iov_virtual_addr(const struct net_iov *niov) +{ + struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov); + + return owner->base_virtual + + ((unsigned long)net_iov_idx(niov) << PAGE_SHIFT); +} + +static inline u32 net_iov_binding_id(const struct net_iov *niov) +{ + return net_iov_owner(niov)->binding->id; +} + static inline struct net_devmem_dmabuf_binding * net_iov_binding(const struct net_iov *niov) { diff --git a/include/net/sock.h b/include/net/sock.h index f51d61fab059..c58ca8dd561b 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -337,6 +337,7 @@ struct sk_filter; * @sk_txtime_report_errors: set report errors mode for SO_TXTIME * @sk_txtime_unused: unused txtime flags * @ns_tracker: tracker for netns reference + * @sk_user_frags: xarray of pages the user is holding a reference on. */ struct sock { /* @@ -542,6 +543,7 @@ struct sock { #endif struct rcu_head sk_rcu; netns_tracker ns_tracker; + struct xarray sk_user_frags; };

struct sock_bh_locked { diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h index 8ce8a39a1e5f..e993edc9c0ee 100644 --- a/include/uapi/asm-generic/socket.h +++ b/include/uapi/asm-generic/socket.h @@ -135,6 +135,11 @@ #define SO_PASSPIDFD 76 #define SO_PEERPIDFD 77

+#define SO_DEVMEM_LINEAR 78 +#define SCM_DEVMEM_LINEAR SO_DEVMEM_LINEAR +#define SO_DEVMEM_DMABUF 79 +#define SCM_DEVMEM_DMABUF SO_DEVMEM_DMABUF + #if !defined(__KERNEL__)

#if __BITS_PER_LONG == 64 || (defined(__x86_64__) && defined(__ILP32__)) diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h index 059b1a9147f4..3a22ddae376a 100644 --- a/include/uapi/linux/uio.h +++ b/include/uapi/linux/uio.h @@ -20,6 +20,19 @@ struct iovec __kernel_size_t iov_len; /* Must be size_t (1003.1g) */ };

+struct dmabuf_cmsg { + __u64 frag_offset; /* offset into the dmabuf where the frag starts. + */ + __u32 frag_size; /* size of the frag. */ + __u32 frag_token; /* token representing this frag for + * DEVMEM_DONTNEED. + */ + __u32 dmabuf_id; /* dmabuf id this frag belongs to. */ + __u32 flags; /* Currently unused. Reserved for future + * uses. + */ +}; + /* * UIO_MAXIOV shall be at least 16 1003.1g (5.4.1.1) */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 30238963fe99..93cb76813bf1 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -471,6 +471,7 @@ void tcp_init_sock(struct sock *sk)

set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags); sk_sockets_allocated_inc(sk); + xa_init_flags(&sk->sk_user_frags, XA_FLAGS_ALLOC1); } EXPORT_SYMBOL(tcp_init_sock);

@@ -2323,6 +2324,220 @@ static int tcp_inq_hint(struct sock *sk) return inq; }

+/* batch __xa_alloc() calls and reduce xa_lock()/xa_unlock() overhead. */ +struct tcp_xa_pool { + u8 max; /* max <= MAX_SKB_FRAGS */ + u8 idx; /* idx <= max */ + __u32 tokens[MAX_SKB_FRAGS]; + netmem_ref netmems[MAX_SKB_FRAGS]; +}; + +static void tcp_xa_pool_commit_locked(struct sock *sk, struct tcp_xa_pool *p) +{ + int i; + + /* Commit part that has been copied to user space. */ + for (i = 0; i < p->idx; i++) + __xa_cmpxchg(&sk->sk_user_frags, p->tokens[i], XA_ZERO_ENTRY, + (__force void *)p->netmems[i], GFP_KERNEL); + /* Rollback what has been pre-allocated and is no longer needed. */ + for (; i < p->max; i++) + __xa_erase(&sk->sk_user_frags, p->tokens[i]); + + p->max = 0; + p->idx = 0; +} + +static void tcp_xa_pool_commit(struct sock *sk, struct tcp_xa_pool *p) +{ + if (!p->max) + return; + + xa_lock_bh(&sk->sk_user_frags); + + tcp_xa_pool_commit_locked(sk, p); + + xa_unlock_bh(&sk->sk_user_frags); +} + +static int tcp_xa_pool_refill(struct sock *sk, struct tcp_xa_pool *p, + unsigned int max_frags) +{ + int err, k; + + if (p->idx < p->max) + return 0; + + xa_lock_bh(&sk->sk_user_frags); + + tcp_xa_pool_commit_locked(sk, p); + + for (k = 0; k < max_frags; k++) { + err = __xa_alloc(&sk->sk_user_frags, &p->tokens[k], + XA_ZERO_ENTRY, xa_limit_31b, GFP_KERNEL); + if (err) + break; + } + + xa_unlock_bh(&sk->sk_user_frags); + + p->max = k; + p->idx = 0; + return k ? 0 : err; +} + +/* On error, returns the -errno. On success, returns number of bytes sent to the + * user. May not consume all of @remaining_len. + */ +static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb, + unsigned int offset, struct msghdr *msg, + int remaining_len) +{ + struct dmabuf_cmsg dmabuf_cmsg = { 0 }; + struct tcp_xa_pool tcp_xa_pool; + unsigned int start; + int i, copy, n; + int sent = 0; + int err = 0; + + tcp_xa_pool.max = 0; + tcp_xa_pool.idx = 0; + do { + start = skb_headlen(skb); + + if (skb_frags_readable(skb)) { + err = -ENODEV; + goto out; + } + + /* Copy header. */ + copy = start - offset; + if (copy > 0) { + copy = min(copy, remaining_len); + + n = copy_to_iter(skb->data + offset, copy, + &msg->msg_iter); + if (n != copy) { + err = -EFAULT; + goto out; + } + + offset += copy; + remaining_len -= copy; + + /* First a dmabuf_cmsg for # bytes copied to user + * buffer. + */ + memset(&dmabuf_cmsg, 0, sizeof(dmabuf_cmsg)); + dmabuf_cmsg.frag_size = copy; + err = put_cmsg(msg, SOL_SOCKET, SO_DEVMEM_LINEAR, + sizeof(dmabuf_cmsg), &dmabuf_cmsg); + if (err || msg->msg_flags & MSG_CTRUNC) { + msg->msg_flags &= ~MSG_CTRUNC; + if (!err) + err = -ETOOSMALL; + goto out; + } + + sent += copy; + + if (remaining_len == 0) + goto out; + } + + /* after that, send information of dmabuf pages through a + * sequence of cmsg + */ + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + struct net_iov *niov; + u64 frag_offset; + int end; + + /* !skb_frags_readable() should indicate that ALL the + * frags in this skb are dmabuf net_iovs. We're checking + * for that flag above, but also check individual frags + * here. If the tcp stack is not setting + * skb_frags_readable() correctly, we still don't want + * to crash here. + */ + if (!skb_frag_net_iov(frag)) { + net_err_ratelimited("Found non-dmabuf skb with net_iov"); + err = -ENODEV; + goto out; + } + + niov = skb_frag_net_iov(frag); + end = start + skb_frag_size(frag); + copy = end - offset; + + if (copy > 0) { + copy = min(copy, remaining_len); + + frag_offset = net_iov_virtual_addr(niov) + + skb_frag_off(frag) + offset - + start; + dmabuf_cmsg.frag_offset = frag_offset; + dmabuf_cmsg.frag_size = copy; + err = tcp_xa_pool_refill(sk, &tcp_xa_pool, + skb_shinfo(skb)->nr_frags - i); + if (err) + goto out; + + /* Will perform the exchange later */ + dmabuf_cmsg.frag_token = tcp_xa_pool.tokens[tcp_xa_pool.idx]; + dmabuf_cmsg.dmabuf_id = net_iov_binding_id(niov); + + offset += copy; + remaining_len -= copy; + + err = put_cmsg(msg, SOL_SOCKET, + SO_DEVMEM_DMABUF, + sizeof(dmabuf_cmsg), + &dmabuf_cmsg); + if (err || msg->msg_flags & MSG_CTRUNC) { + msg->msg_flags &= ~MSG_CTRUNC; + if (!err) + err = -ETOOSMALL; + goto out; + } + + atomic_long_inc(&niov->pp_ref_count); + tcp_xa_pool.netmems[tcp_xa_pool.idx++] = skb_frag_netmem(frag); + + sent += copy; + + if (remaining_len == 0) + goto out; + } + start = end; + } + + tcp_xa_pool_commit(sk, &tcp_xa_pool); + if (!remaining_len) + goto out; + + /* if remaining_len is not satisfied yet, we need to go to the + * next frag in the frag_list to satisfy remaining_len. + */ + skb = skb_shinfo(skb)->frag_list ?: skb->next; + + offset = offset - start; + } while (skb); + + if (remaining_len) { + err = -EFAULT; + goto out; + } + +out: + tcp_xa_pool_commit(sk, &tcp_xa_pool); + if (!sent) + sent = err; + + return sent; +} + /* * This routine copies from a sock struct into the user buffer. * @@ -2336,6 +2551,7 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, int *cmsg_flags) { struct tcp_sock *tp = tcp_sk(sk); + int last_copied_dmabuf = -1; /* uninitialized */ int copied = 0; u32 peek_seq; u32 *seq; @@ -2515,15 +2731,44 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, }

if (!(flags & MSG_TRUNC)) { - err = skb_copy_datagram_msg(skb, offset, msg, used); - if (err) { - /* Exception. Bailout! */ - if (!copied) - copied = -EFAULT; + if (last_copied_dmabuf != -1 && + last_copied_dmabuf != !skb_frags_readable(skb)) break; + + if (skb_frags_readable(skb)) { + err = skb_copy_datagram_msg(skb, offset, msg, + used); + if (err) { + /* Exception. Bailout! */ + if (!copied) + copied = -EFAULT; + break; + } + } else { + if (!(flags & MSG_SOCK_DEVMEM)) { + /* dmabuf skbs can only be received + * with the MSG_SOCK_DEVMEM flag. + */ + if (!copied) + copied = -EFAULT; + + break; + } + + err = tcp_recvmsg_dmabuf(sk, skb, offset, msg, + used); + if (err <= 0) { + if (!copied) + copied = -EFAULT; + + break; + } + used = err; } }

+ last_copied_dmabuf = !skb_frags_readable(skb); + WRITE_ONCE(*seq, *seq + used); copied += used; len -= used; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index eb631e66ee03..5afe5e57c89b 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -79,6 +79,7 @@ #include <linux/seq_file.h> #include <linux/inetdevice.h> #include <linux/btf_ids.h> +#include <linux/skbuff_ref.h>

#include <crypto/hash.h> #include <linux/scatterlist.h> @@ -2512,10 +2513,25 @@ static void tcp_md5sig_info_free_rcu(struct rcu_head *head) } #endif

+static void tcp_release_user_frags(struct sock *sk) +{ +#ifdef CONFIG_PAGE_POOL + unsigned long index; + void *netmem; + + xa_for_each(&sk->sk_user_frags, index, netmem) + WARN_ON_ONCE(!napi_pp_put_page((__force netmem_ref)netmem)); +#endif +} + void tcp_v4_destroy_sock(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk);

+ tcp_release_user_frags(sk); + + xa_destroy(&sk->sk_user_frags); + trace_tcp_destroy_sock(sk);

tcp_clear_xmit_timers(sk); diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index ad562272db2e..bb1fe1ba867a 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -628,6 +628,8 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,

__TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);

+ xa_init_flags(&newsk->sk_user_frags, XA_FLAGS_ALLOC1); + return newsk; } EXPORT_SYMBOL(tcp_create_openreq_child);

Add documentation outlining the usage and details of devmem TCP.

Signed-off-by: Mina Almasry almasrymina@google.com Reviewed-by: Bagas Sanjaya bagasdotme@gmail.com Reviewed-by: Donald Hunter donald.hunter@gmail.com

---

v16: - Add documentation on unbinding the NIC from dmabuf (Donald). - Add note that any dmabuf should work (Donald).

v9: https://lore.kernel.org/netdev/20240403002053.2376017-14-almasrymina@google.... - Bagas doc suggestions.

v8: - Applied docs suggestions (Randy). Thanks!

v7: - Applied docs suggestions (Jakub).

v2:

- Missing spdx (simon) - add to index.rst (simon)

--- Documentation/networking/devmem.rst | 269 ++++++++++++++++++++++++++++ Documentation/networking/index.rst | 1 + 2 files changed, 270 insertions(+) create mode 100644 Documentation/networking/devmem.rst

diff --git a/Documentation/networking/devmem.rst b/Documentation/networking/devmem.rst new file mode 100644 index 000000000000..417fc977844e --- /dev/null +++ b/Documentation/networking/devmem.rst @@ -0,0 +1,269 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Device Memory TCP +================= + + +Intro +===== + +Device memory TCP (devmem TCP) enables receiving data directly into device +memory (dmabuf). The feature is currently implemented for TCP sockets. + + +Opportunity +----------- + +A large number of data transfers have device memory as the source and/or +destination. Accelerators drastically increased the prevalence of such +transfers. Some examples include: + +- Distributed training, where ML accelerators, such as GPUs on different hosts, + exchange data. + +- Distributed raw block storage applications transfer large amounts of data with + remote SSDs. Much of this data does not require host processing. + +Typically the Device-to-Device data transfers in the network are implemented as +the following low-level operations: Device-to-Host copy, Host-to-Host network +transfer, and Host-to-Device copy. + +The flow involving host copies is suboptimal, especially for bulk data transfers, +and can put significant strains on system resources such as host memory +bandwidth and PCIe bandwidth. + +Devmem TCP optimizes this use case by implementing socket APIs that enable +the user to receive incoming network packets directly into device memory. + +Packet payloads go directly from the NIC to device memory. + +Packet headers go to host memory and are processed by the TCP/IP stack +normally. The NIC must support header split to achieve this. + +Advantages: + +- Alleviate host memory bandwidth pressure, compared to existing + network-transfer + device-copy semantics. + +- Alleviate PCIe bandwidth pressure, by limiting data transfer to the lowest + level of the PCIe tree, compared to the traditional path which sends data + through the root complex. + + +More Info +--------- + + slides, video + https://netdevconf.org/0x17/sessions/talk/device-memory-tcp.html + + patchset + [RFC PATCH v6 00/12] Device Memory TCP + https://lore.kernel.org/netdev/20240305020153.2787423-1-almasrymina@google.c... + + +Interface +========= + + +Example +------- + +tools/testing/selftests/net/ncdevmem.c:do_server shows an example of setting up +the RX path of this API. + + +NIC Setup +--------- + +Header split, flow steering, & RSS are required features for devmem TCP. + +Header split is used to split incoming packets into a header buffer in host +memory, and a payload buffer in device memory. + +Flow steering & RSS are used to ensure that only flows targeting devmem land on +an RX queue bound to devmem. + +Enable header split & flow steering:: + + # enable header split + ethtool -G eth1 tcp-data-split on + + + # enable flow steering + ethtool -K eth1 ntuple on + +Configure RSS to steer all traffic away from the target RX queue (queue 15 in +this example):: + + ethtool --set-rxfh-indir eth1 equal 15 + + +The user must bind a dmabuf to any number of RX queues on a given NIC using +the netlink API:: + + /* Bind dmabuf to NIC RX queue 15 */ + struct netdev_queue *queues; + queues = malloc(sizeof(*queues) * 1); + + queues[0]._present.type = 1; + queues[0]._present.idx = 1; + queues[0].type = NETDEV_RX_QUEUE_TYPE_RX; + queues[0].idx = 15; + + *ys = ynl_sock_create(&ynl_netdev_family, &yerr); + + req = netdev_bind_rx_req_alloc(); + netdev_bind_rx_req_set_ifindex(req, 1 /* ifindex */); + netdev_bind_rx_req_set_dmabuf_fd(req, dmabuf_fd); + __netdev_bind_rx_req_set_queues(req, queues, n_queue_index); + + rsp = netdev_bind_rx(*ys, req); + + dmabuf_id = rsp->dmabuf_id; + + +The netlink API returns a dmabuf_id: a unique ID that refers to this dmabuf +that has been bound. + +The user can unbind the dmabuf from the netdevice by closing the netlink socket +that established the binding. We do this so that the binding is automatically +unbound even if the userspace process crashes. + +Note that any reasonably well-behaved dmabuf from any exporter should work with +devmem TCP, even if the dmabuf is not actually backed by devmem. An example of +this is udmabuf, which wraps user memory (non-devmem) in a dmabuf. + + +Socket Setup +------------ + +The socket must be flow steered to the dmabuf bound RX queue:: + + ethtool -N eth1 flow-type tcp4 ... queue 15, + + +Receiving data +-------------- + +The user application must signal to the kernel that it is capable of receiving +devmem data by passing the MSG_SOCK_DEVMEM flag to recvmsg:: + + ret = recvmsg(fd, &msg, MSG_SOCK_DEVMEM); + +Applications that do not specify the MSG_SOCK_DEVMEM flag will receive an EFAULT +on devmem data. + +Devmem data is received directly into the dmabuf bound to the NIC in 'NIC +Setup', and the kernel signals such to the user via the SCM_DEVMEM_* cmsgs:: + + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) { + if (cm->cmsg_level != SOL_SOCKET || + (cm->cmsg_type != SCM_DEVMEM_DMABUF && + cm->cmsg_type != SCM_DEVMEM_LINEAR)) + continue; + + dmabuf_cmsg = (struct dmabuf_cmsg *)CMSG_DATA(cm); + + if (cm->cmsg_type == SCM_DEVMEM_DMABUF) { + /* Frag landed in dmabuf. + * + * dmabuf_cmsg->dmabuf_id is the dmabuf the + * frag landed on. + * + * dmabuf_cmsg->frag_offset is the offset into + * the dmabuf where the frag starts. + * + * dmabuf_cmsg->frag_size is the size of the + * frag. + * + * dmabuf_cmsg->frag_token is a token used to + * refer to this frag for later freeing. + */ + + struct dmabuf_token token; + token.token_start = dmabuf_cmsg->frag_token; + token.token_count = 1; + continue; + } + + if (cm->cmsg_type == SCM_DEVMEM_LINEAR) + /* Frag landed in linear buffer. + * + * dmabuf_cmsg->frag_size is the size of the + * frag. + */ + continue; + + } + +Applications may receive 2 cmsgs: + +- SCM_DEVMEM_DMABUF: this indicates the fragment landed in the dmabuf indicated + by dmabuf_id. + +- SCM_DEVMEM_LINEAR: this indicates the fragment landed in the linear buffer. + This typically happens when the NIC is unable to split the packet at the + header boundary, such that part (or all) of the payload landed in host + memory. + +Applications may receive no SO_DEVMEM_* cmsgs. That indicates non-devmem, +regular TCP data that landed on an RX queue not bound to a dmabuf. + + +Freeing frags +------------- + +Frags received via SCM_DEVMEM_DMABUF are pinned by the kernel while the user +processes the frag. The user must return the frag to the kernel via +SO_DEVMEM_DONTNEED:: + + ret = setsockopt(client_fd, SOL_SOCKET, SO_DEVMEM_DONTNEED, &token, + sizeof(token)); + +The user must ensure the tokens are returned to the kernel in a timely manner. +Failure to do so will exhaust the limited dmabuf that is bound to the RX queue +and will lead to packet drops. + + +Implementation & Caveats +======================== + +Unreadable skbs +--------------- + +Devmem payloads are inaccessible to the kernel processing the packets. This +results in a few quirks for payloads of devmem skbs: + +- Loopback is not functional. Loopback relies on copying the payload, which is + not possible with devmem skbs. + +- Software checksum calculation fails. + +- TCP Dump and bpf can't access devmem packet payloads. + + +Testing +======= + +More realistic example code can be found in the kernel source under +tools/testing/selftests/net/ncdevmem.c + +ncdevmem is a devmem TCP netcat. It works very similarly to netcat, but +receives data directly into a udmabuf. + +To run ncdevmem, you need to run it on a server on the machine under test, and +you need to run netcat on a peer to provide the TX data. + +ncdevmem has a validation mode as well that expects a repeating pattern of +incoming data and validates it as such. For example, you can launch +ncdevmem on the server by:: + + ncdevmem -s <server IP> -c <client IP> -f eth1 -d 3 -n 0000:06:00.0 -l \ + -p 5201 -v 7 + +On client side, use regular netcat to send TX data to ncdevmem process +on the server:: + + yes $(echo -e \x01\x02\x03\x04\x05\x06) | \ + tr \n \0 | head -c 5G | nc <server IP> 5201 -p 5201 diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index c71b87346178..08f437c326ab 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -49,6 +49,7 @@ Contents: cdc_mbim dccp dctcp + devmem dns_resolver driver eql

ncdevmem is a devmem TCP netcat. It works similarly to netcat, but it sends and receives data using the devmem TCP APIs. It uses udmabuf as the dmabuf provider. It is compatible with a regular netcat running on a peer, or a ncdevmem running on a peer.

In addition to normal netcat support, ncdevmem has a validation mode, where it sends a specific pattern and validates this pattern on the receiver side to ensure data integrity.

Suggested-by: Stanislav Fomichev sdf@fomichev.me Signed-off-by: Mina Almasry almasrymina@google.com

---

v24: - Add *.d to .gitignore, to stop tracking this file the build generates:

``` git status ... ?? tools/net/ynl/lib/ynl.d ```

v22: - Add run_command helper. It reduces boiler plate and prints the commands it is running.

v20: - Remove unnecessary sleep(1) - Add test to ensure dmabuf binding fails if header split is disabled.

v19: - Check return code of ethtool commands. - Add test for deactivating mp bound rx queues - Add test for attempting to bind with missing netlink attributes.

v16: - Remove outdated -n option (Taehee). - Use 'ifname' instead of accidentally hardcoded 'eth1'. (Taehee) - Remove dead code 'iterations' (Taehee). - Use if_nametoindex() instead of passing device index (Taehee).

v15: - Fix linking against libynl. (Jakub)

v9: https://lore.kernel.org/netdev/20240403002053.2376017-15-almasrymina@google.... - Remove unused nic_pci_addr entry (Cong).

v6: - Updated to bind 8 queues. - Added RSS configuration. - Added some more tests for the netlink API.

Changes in v1: - Many more general cleanups (Willem). - Removed driver reset (Jakub). - Removed hardcoded if index (Paolo).

RFC v2: - General cleanups (Willem).

--- tools/net/ynl/lib/.gitignore | 1 + tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 9 + tools/testing/selftests/net/ncdevmem.c | 570 +++++++++++++++++++++++++ 4 files changed, 581 insertions(+) create mode 100644 tools/testing/selftests/net/ncdevmem.c

diff --git a/tools/net/ynl/lib/.gitignore b/tools/net/ynl/lib/.gitignore index c18dd8d83cee..296c4035dbf2 100644 --- a/tools/net/ynl/lib/.gitignore +++ b/tools/net/ynl/lib/.gitignore @@ -1 +1,2 @@ __pycache__/ +*.d diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index 666ab7d9390b..fe770903118c 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -17,6 +17,7 @@ ipv6_flowlabel ipv6_flowlabel_mgr log.txt msg_zerocopy +ncdevmem nettest psock_fanout psock_snd diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 1179e3261bef..918ec48f152b 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -96,6 +96,11 @@ TEST_PROGS += fq_band_pktlimit.sh TEST_PROGS += vlan_hw_filter.sh TEST_PROGS += bpf_offload.py

+# YNL files, must be before "include ..lib.mk" +EXTRA_CLEAN += $(OUTPUT)/libynl.a +YNL_GEN_FILES := ncdevmem +TEST_GEN_FILES += $(YNL_GEN_FILES) + TEST_FILES := settings TEST_FILES += in_netns.sh lib.sh net_helper.sh setup_loopback.sh setup_veth.sh

@@ -105,6 +110,10 @@ TEST_INCLUDES := forwarding/lib.sh

include ../lib.mk

+# YNL build +YNL_GENS := netdev +include ynl.mk + $(OUTPUT)/epoll_busy_poll: LDLIBS += -lcap $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread -lcrypto diff --git a/tools/testing/selftests/net/ncdevmem.c b/tools/testing/selftests/net/ncdevmem.c new file mode 100644 index 000000000000..64d6805381c5 --- /dev/null +++ b/tools/testing/selftests/net/ncdevmem.c @@ -0,0 +1,570 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#define __EXPORTED_HEADERS__ + +#include <linux/uio.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <stdbool.h> +#include <string.h> +#include <errno.h> +#define __iovec_defined +#include <fcntl.h> +#include <malloc.h> +#include <error.h> + +#include <arpa/inet.h> +#include <sys/socket.h> +#include <sys/mman.h> +#include <sys/ioctl.h> +#include <sys/syscall.h> + +#include <linux/memfd.h> +#include <linux/dma-buf.h> +#include <linux/udmabuf.h> +#include <libmnl/libmnl.h> +#include <linux/types.h> +#include <linux/netlink.h> +#include <linux/genetlink.h> +#include <linux/netdev.h> +#include <time.h> +#include <net/if.h> + +#include "netdev-user.h" +#include <ynl.h> + +#define PAGE_SHIFT 12 +#define TEST_PREFIX "ncdevmem" +#define NUM_PAGES 16000 + +#ifndef MSG_SOCK_DEVMEM +#define MSG_SOCK_DEVMEM 0x2000000 +#endif + +/* + * tcpdevmem netcat. Works similarly to netcat but does device memory TCP + * instead of regular TCP. Uses udmabuf to mock a dmabuf provider. + * + * Usage: + * + * On server: + * ncdevmem -s <server IP> -c <client IP> -f eth1 -l -p 5201 -v 7 + * + * On client: + * yes $(echo -e \x01\x02\x03\x04\x05\x06) | \ + * tr \n \0 | \ + * head -c 5G | \ + * nc <server IP> 5201 -p 5201 + * + * Note this is compatible with regular netcat. i.e. the sender or receiver can + * be replaced with regular netcat to test the RX or TX path in isolation. + */ + +static char *server_ip = "192.168.1.4"; +static char *client_ip = "192.168.1.2"; +static char *port = "5201"; +static size_t do_validation; +static int start_queue = 8; +static int num_queues = 8; +static char *ifname = "eth1"; +static unsigned int ifindex; +static unsigned int dmabuf_id; + +void print_bytes(void *ptr, size_t size) +{ + unsigned char *p = ptr; + int i; + + for (i = 0; i < size; i++) + printf("%02hhX ", p[i]); + printf("\n"); +} + +void print_nonzero_bytes(void *ptr, size_t size) +{ + unsigned char *p = ptr; + unsigned int i; + + for (i = 0; i < size; i++) + putchar(p[i]); + printf("\n"); +} + +void validate_buffer(void *line, size_t size) +{ + static unsigned char seed = 1; + unsigned char *ptr = line; + int errors = 0; + size_t i; + + for (i = 0; i < size; i++) { + if (ptr[i] != seed) { + fprintf(stderr, + "Failed validation: expected=%u, actual=%u, index=%lu\n", + seed, ptr[i], i); + errors++; + if (errors > 20) + error(1, 0, "validation failed."); + } + seed++; + if (seed == do_validation) + seed = 0; + } + + fprintf(stdout, "Validated buffer\n"); +} + +#define run_command(cmd, ...) \ + ({ \ + char command[256]; \ + memset(command, 0, sizeof(command)); \ + snprintf(command, sizeof(command), cmd, ##__VA_ARGS__); \ + printf("Running: %s\n", command); \ + system(command); \ + }) + +static int reset_flow_steering(void) +{ + int ret = 0; + + ret = run_command("sudo ethtool -K %s ntuple off", ifname); + if (ret) + return ret; + + return run_command("sudo ethtool -K %s ntuple on", ifname); +} + +static int configure_headersplit(bool on) +{ + return run_command("sudo ethtool -G %s tcp-data-split %s", ifname, + on ? "on" : "off"); +} + +static int configure_rss(void) +{ + return run_command("sudo ethtool -X %s equal %d", ifname, start_queue); +} + +static int configure_channels(unsigned int rx, unsigned int tx) +{ + return run_command("sudo ethtool -L %s rx %u tx %u", ifname, rx, tx); +} + +static int configure_flow_steering(void) +{ + return run_command("sudo ethtool -N %s flow-type tcp4 src-ip %s dst-ip %s src-port %s dst-port %s queue %d", + ifname, client_ip, server_ip, port, port, start_queue); +} + +static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd, + struct netdev_queue_id *queues, + unsigned int n_queue_index, struct ynl_sock **ys) +{ + struct netdev_bind_rx_req *req = NULL; + struct netdev_bind_rx_rsp *rsp = NULL; + struct ynl_error yerr; + + *ys = ynl_sock_create(&ynl_netdev_family, &yerr); + if (!*ys) { + fprintf(stderr, "YNL: %s\n", yerr.msg); + return -1; + } + + req = netdev_bind_rx_req_alloc(); + netdev_bind_rx_req_set_ifindex(req, ifindex); + netdev_bind_rx_req_set_fd(req, dmabuf_fd); + __netdev_bind_rx_req_set_queues(req, queues, n_queue_index); + + rsp = netdev_bind_rx(*ys, req); + if (!rsp) { + perror("netdev_bind_rx"); + goto err_close; + } + + if (!rsp->_present.id) { + perror("id not present"); + goto err_close; + } + + printf("got dmabuf id=%d\n", rsp->id); + dmabuf_id = rsp->id; + + netdev_bind_rx_req_free(req); + netdev_bind_rx_rsp_free(rsp); + + return 0; + +err_close: + fprintf(stderr, "YNL failed: %s\n", (*ys)->err.msg); + netdev_bind_rx_req_free(req); + ynl_sock_destroy(*ys); + return -1; +} + +static void create_udmabuf(int *devfd, int *memfd, int *buf, size_t dmabuf_size) +{ + struct udmabuf_create create; + int ret; + + *devfd = open("/dev/udmabuf", O_RDWR); + if (*devfd < 0) { + error(70, 0, + "%s: [skip,no-udmabuf: Unable to access DMA buffer device file]\n", + TEST_PREFIX); + } + + *memfd = memfd_create("udmabuf-test", MFD_ALLOW_SEALING); + if (*memfd < 0) + error(70, 0, "%s: [skip,no-memfd]\n", TEST_PREFIX); + + /* Required for udmabuf */ + ret = fcntl(*memfd, F_ADD_SEALS, F_SEAL_SHRINK); + if (ret < 0) + error(73, 0, "%s: [skip,fcntl-add-seals]\n", TEST_PREFIX); + + ret = ftruncate(*memfd, dmabuf_size); + if (ret == -1) + error(74, 0, "%s: [FAIL,memfd-truncate]\n", TEST_PREFIX); + + memset(&create, 0, sizeof(create)); + + create.memfd = *memfd; + create.offset = 0; + create.size = dmabuf_size; + *buf = ioctl(*devfd, UDMABUF_CREATE, &create); + if (*buf < 0) + error(75, 0, "%s: [FAIL, create udmabuf]\n", TEST_PREFIX); +} + +int do_server(void) +{ + char ctrl_data[sizeof(int) * 20000]; + struct netdev_queue_id *queues; + size_t non_page_aligned_frags = 0; + struct sockaddr_in client_addr; + struct sockaddr_in server_sin; + size_t page_aligned_frags = 0; + int devfd, memfd, buf, ret; + size_t total_received = 0; + socklen_t client_addr_len; + bool is_devmem = false; + char *buf_mem = NULL; + struct ynl_sock *ys; + size_t dmabuf_size; + char iobuf[819200]; + char buffer[256]; + int socket_fd; + int client_fd; + size_t i = 0; + int opt = 1; + + dmabuf_size = getpagesize() * NUM_PAGES; + + create_udmabuf(&devfd, &memfd, &buf, dmabuf_size); + + if (reset_flow_steering()) + error(1, 0, "Failed to reset flow steering\n"); + + /* Configure RSS to divert all traffic from our devmem queues */ + if (configure_rss()) + error(1, 0, "Failed to configure rss\n"); + + /* Flow steer our devmem flows to start_queue */ + if (configure_flow_steering()) + error(1, 0, "Failed to configure flow steering\n"); + + sleep(1); + + queues = malloc(sizeof(*queues) * num_queues); + + for (i = 0; i < num_queues; i++) { + queues[i]._present.type = 1; + queues[i]._present.id = 1; + queues[i].type = NETDEV_QUEUE_TYPE_RX; + queues[i].id = start_queue + i; + } + + if (bind_rx_queue(ifindex, buf, queues, num_queues, &ys)) + error(1, 0, "Failed to bind\n"); + + buf_mem = mmap(NULL, dmabuf_size, PROT_READ | PROT_WRITE, MAP_SHARED, + buf, 0); + if (buf_mem == MAP_FAILED) + error(1, 0, "mmap()"); + + server_sin.sin_family = AF_INET; + server_sin.sin_port = htons(atoi(port)); + + ret = inet_pton(server_sin.sin_family, server_ip, &server_sin.sin_addr); + if (socket < 0) + error(79, 0, "%s: [FAIL, create socket]\n", TEST_PREFIX); + + socket_fd = socket(server_sin.sin_family, SOCK_STREAM, 0); + if (socket < 0) + error(errno, errno, "%s: [FAIL, create socket]\n", TEST_PREFIX); + + ret = setsockopt(socket_fd, SOL_SOCKET, SO_REUSEPORT, &opt, + sizeof(opt)); + if (ret) + error(errno, errno, "%s: [FAIL, set sock opt]\n", TEST_PREFIX); + + ret = setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &opt, + sizeof(opt)); + if (ret) + error(errno, errno, "%s: [FAIL, set sock opt]\n", TEST_PREFIX); + + printf("binding to address %s:%d\n", server_ip, + ntohs(server_sin.sin_port)); + + ret = bind(socket_fd, &server_sin, sizeof(server_sin)); + if (ret) + error(errno, errno, "%s: [FAIL, bind]\n", TEST_PREFIX); + + ret = listen(socket_fd, 1); + if (ret) + error(errno, errno, "%s: [FAIL, listen]\n", TEST_PREFIX); + + client_addr_len = sizeof(client_addr); + + inet_ntop(server_sin.sin_family, &server_sin.sin_addr, buffer, + sizeof(buffer)); + printf("Waiting or connection on %s:%d\n", buffer, + ntohs(server_sin.sin_port)); + client_fd = accept(socket_fd, &client_addr, &client_addr_len); + + inet_ntop(client_addr.sin_family, &client_addr.sin_addr, buffer, + sizeof(buffer)); + printf("Got connection from %s:%d\n", buffer, + ntohs(client_addr.sin_port)); + + while (1) { + struct iovec iov = { .iov_base = iobuf, + .iov_len = sizeof(iobuf) }; + struct dmabuf_cmsg *dmabuf_cmsg = NULL; + struct dma_buf_sync sync = { 0 }; + struct cmsghdr *cm = NULL; + struct msghdr msg = { 0 }; + struct dmabuf_token token; + ssize_t ret; + + is_devmem = false; + printf("\n\n"); + + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + msg.msg_control = ctrl_data; + msg.msg_controllen = sizeof(ctrl_data); + ret = recvmsg(client_fd, &msg, MSG_SOCK_DEVMEM); + printf("recvmsg ret=%ld\n", ret); + if (ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) + continue; + if (ret < 0) { + perror("recvmsg"); + continue; + } + if (ret == 0) { + printf("client exited\n"); + goto cleanup; + } + + i++; + for (cm = CMSG_FIRSTHDR(&msg); cm; cm = CMSG_NXTHDR(&msg, cm)) { + if (cm->cmsg_level != SOL_SOCKET || + (cm->cmsg_type != SCM_DEVMEM_DMABUF && + cm->cmsg_type != SCM_DEVMEM_LINEAR)) { + fprintf(stdout, "skipping non-devmem cmsg\n"); + continue; + } + + dmabuf_cmsg = (struct dmabuf_cmsg *)CMSG_DATA(cm); + is_devmem = true; + + if (cm->cmsg_type == SCM_DEVMEM_LINEAR) { + /* TODO: process data copied from skb's linear + * buffer. + */ + fprintf(stdout, + "SCM_DEVMEM_LINEAR. dmabuf_cmsg->frag_size=%u\n", + dmabuf_cmsg->frag_size); + + continue; + } + + token.token_start = dmabuf_cmsg->frag_token; + token.token_count = 1; + + total_received += dmabuf_cmsg->frag_size; + printf("received frag_page=%llu, in_page_offset=%llu, frag_offset=%llu, frag_size=%u, token=%u, total_received=%lu, dmabuf_id=%u\n", + dmabuf_cmsg->frag_offset >> PAGE_SHIFT, + dmabuf_cmsg->frag_offset % getpagesize(), + dmabuf_cmsg->frag_offset, dmabuf_cmsg->frag_size, + dmabuf_cmsg->frag_token, total_received, + dmabuf_cmsg->dmabuf_id); + + if (dmabuf_cmsg->dmabuf_id != dmabuf_id) + error(1, 0, + "received on wrong dmabuf_id: flow steering error\n"); + + if (dmabuf_cmsg->frag_size % getpagesize()) + non_page_aligned_frags++; + else + page_aligned_frags++; + + sync.flags = DMA_BUF_SYNC_READ | DMA_BUF_SYNC_START; + ioctl(buf, DMA_BUF_IOCTL_SYNC, &sync); + + if (do_validation) + validate_buffer( + ((unsigned char *)buf_mem) + + dmabuf_cmsg->frag_offset, + dmabuf_cmsg->frag_size); + else + print_nonzero_bytes( + ((unsigned char *)buf_mem) + + dmabuf_cmsg->frag_offset, + dmabuf_cmsg->frag_size); + + sync.flags = DMA_BUF_SYNC_READ | DMA_BUF_SYNC_END; + ioctl(buf, DMA_BUF_IOCTL_SYNC, &sync); + + ret = setsockopt(client_fd, SOL_SOCKET, + SO_DEVMEM_DONTNEED, &token, + sizeof(token)); + if (ret != 1) + error(1, 0, + "SO_DEVMEM_DONTNEED not enough tokens"); + } + if (!is_devmem) + error(1, 0, "flow steering error\n"); + + printf("total_received=%lu\n", total_received); + } + + fprintf(stdout, "%s: ok\n", TEST_PREFIX); + + fprintf(stdout, "page_aligned_frags=%lu, non_page_aligned_frags=%lu\n", + page_aligned_frags, non_page_aligned_frags); + + fprintf(stdout, "page_aligned_frags=%lu, non_page_aligned_frags=%lu\n", + page_aligned_frags, non_page_aligned_frags); + +cleanup: + + munmap(buf_mem, dmabuf_size); + close(client_fd); + close(socket_fd); + close(buf); + close(memfd); + close(devfd); + ynl_sock_destroy(ys); + + return 0; +} + +void run_devmem_tests(void) +{ + struct netdev_queue_id *queues; + int devfd, memfd, buf; + struct ynl_sock *ys; + size_t dmabuf_size; + size_t i = 0; + + dmabuf_size = getpagesize() * NUM_PAGES; + + create_udmabuf(&devfd, &memfd, &buf, dmabuf_size); + + /* Configure RSS to divert all traffic from our devmem queues */ + if (configure_rss()) + error(1, 0, "rss error\n"); + + queues = calloc(num_queues, sizeof(*queues)); + + if (configure_headersplit(1)) + error(1, 0, "Failed to configure header split\n"); + + if (!bind_rx_queue(ifindex, buf, queues, num_queues, &ys)) + error(1, 0, "Binding empty queues array should have failed\n"); + + for (i = 0; i < num_queues; i++) { + queues[i]._present.type = 1; + queues[i]._present.id = 1; + queues[i].type = NETDEV_QUEUE_TYPE_RX; + queues[i].id = start_queue + i; + } + + if (configure_headersplit(0)) + error(1, 0, "Failed to configure header split\n"); + + if (!bind_rx_queue(ifindex, buf, queues, num_queues, &ys)) + error(1, 0, "Configure dmabuf with header split off should have failed\n"); + + if (configure_headersplit(1)) + error(1, 0, "Failed to configure header split\n"); + + for (i = 0; i < num_queues; i++) { + queues[i]._present.type = 1; + queues[i]._present.id = 1; + queues[i].type = NETDEV_QUEUE_TYPE_RX; + queues[i].id = start_queue + i; + } + + if (bind_rx_queue(ifindex, buf, queues, num_queues, &ys)) + error(1, 0, "Failed to bind\n"); + + /* Deactivating a bound queue should not be legal */ + if (!configure_channels(num_queues, num_queues - 1)) + error(1, 0, "Deactivating a bound queue should be illegal.\n"); + + /* Closing the netlink socket does an implicit unbind */ + ynl_sock_destroy(ys); +} + +int main(int argc, char *argv[]) +{ + int is_server = 0, opt; + + while ((opt = getopt(argc, argv, "ls:c:p:v:q:t:f:")) != -1) { + switch (opt) { + case 'l': + is_server = 1; + break; + case 's': + server_ip = optarg; + break; + case 'c': + client_ip = optarg; + break; + case 'p': + port = optarg; + break; + case 'v': + do_validation = atoll(optarg); + break; + case 'q': + num_queues = atoi(optarg); + break; + case 't': + start_queue = atoi(optarg); + break; + case 'f': + ifname = optarg; + break; + case '?': + printf("unknown option: %c\n", optopt); + break; + } + } + + ifindex = if_nametoindex(ifname); + + for (; optind < argc; optind++) + printf("extra arguments: %s\n", argv[optind]); + + run_devmem_tests(); + + if (is_server) + return do_server(); + + return 0; +}