6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jakub Kicinski kuba@kernel.org
[ Upstream commit 67e4bb2ced0f2d8fbd414f932daea94ba63ae4c4 ]
Page ppol tried to cache the NAPI ID in page pool info to avoid having a dependency on the life cycle of the NAPI instance. Since commit under Fixes the NAPI ID is not populated until napi_enable() and there's a good chance that page pool is created before NAPI gets enabled.
Protect the NAPI pointer with the existing page pool mutex, the reading path already holds it. napi_id itself we need to READ_ONCE(), it's protected by netdev_lock() which are not holding in page pool.
Before this patch napi IDs were missing for mlx5:
# ./cli.py --spec netlink/specs/netdev.yaml --dump page-pool-get
[{'id': 144, 'ifindex': 2, 'inflight': 3072, 'inflight-mem': 12582912}, {'id': 143, 'ifindex': 2, 'inflight': 5568, 'inflight-mem': 22806528}, {'id': 142, 'ifindex': 2, 'inflight': 5120, 'inflight-mem': 20971520}, {'id': 141, 'ifindex': 2, 'inflight': 4992, 'inflight-mem': 20447232}, ...
After:
[{'id': 144, 'ifindex': 2, 'inflight': 3072, 'inflight-mem': 12582912, 'napi-id': 565}, {'id': 143, 'ifindex': 2, 'inflight': 4224, 'inflight-mem': 17301504, 'napi-id': 525}, {'id': 142, 'ifindex': 2, 'inflight': 4288, 'inflight-mem': 17563648, 'napi-id': 524}, ...
Fixes: 86e25f40aa1e ("net: napi: Add napi_config") Reviewed-by: Mina Almasry almasrymina@google.com Reviewed-by: Toke Høiland-Jørgensen toke@redhat.com Link: https://patch.msgid.link/20250123231620.1086401-1-kuba@kernel.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/page_pool/types.h | 1 - net/core/dev.c | 2 +- net/core/page_pool.c | 2 ++ net/core/page_pool_priv.h | 2 ++ net/core/page_pool_user.c | 15 +++++++++------ 5 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h index c022c410abe39..386efddd2aac0 100644 --- a/include/net/page_pool/types.h +++ b/include/net/page_pool/types.h @@ -236,7 +236,6 @@ struct page_pool { struct { struct hlist_node list; u64 detach_time; - u32 napi_id; u32 id; } user; }; diff --git a/net/core/dev.c b/net/core/dev.c index 71988f2f484b2..a994b1c725098 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6573,7 +6573,7 @@ void napi_resume_irqs(unsigned int napi_id) static void __napi_hash_add_with_id(struct napi_struct *napi, unsigned int napi_id) { - napi->napi_id = napi_id; + WRITE_ONCE(napi->napi_id, napi_id); hlist_add_head_rcu(&napi->napi_hash_node, &napi_hash[napi->napi_id % HASH_SIZE(napi_hash)]); } diff --git a/net/core/page_pool.c b/net/core/page_pool.c index f89cf93f6eb45..32570333068d8 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -1108,7 +1108,9 @@ void page_pool_disable_direct_recycling(struct page_pool *pool) WARN_ON(!test_bit(NAPI_STATE_SCHED, &pool->p.napi->state)); WARN_ON(READ_ONCE(pool->p.napi->list_owner) != -1);
+ mutex_lock(&page_pools_lock); WRITE_ONCE(pool->p.napi, NULL); + mutex_unlock(&page_pools_lock); } EXPORT_SYMBOL(page_pool_disable_direct_recycling);
diff --git a/net/core/page_pool_priv.h b/net/core/page_pool_priv.h index 57439787b9c2b..2fb06d5f6d559 100644 --- a/net/core/page_pool_priv.h +++ b/net/core/page_pool_priv.h @@ -7,6 +7,8 @@
#include "netmem_priv.h"
+extern struct mutex page_pools_lock; + s32 page_pool_inflight(const struct page_pool *pool, bool strict);
int page_pool_list(struct page_pool *pool); diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c index 48335766c1bfd..6677e0c2e2565 100644 --- a/net/core/page_pool_user.c +++ b/net/core/page_pool_user.c @@ -3,6 +3,7 @@ #include <linux/mutex.h> #include <linux/netdevice.h> #include <linux/xarray.h> +#include <net/busy_poll.h> #include <net/net_debug.h> #include <net/netdev_rx_queue.h> #include <net/page_pool/helpers.h> @@ -14,10 +15,11 @@ #include "netdev-genl-gen.h"
static DEFINE_XARRAY_FLAGS(page_pools, XA_FLAGS_ALLOC1); -/* Protects: page_pools, netdevice->page_pools, pool->slow.netdev, pool->user. +/* Protects: page_pools, netdevice->page_pools, pool->p.napi, pool->slow.netdev, + * pool->user. * Ordering: inside rtnl_lock */ -static DEFINE_MUTEX(page_pools_lock); +DEFINE_MUTEX(page_pools_lock);
/* Page pools are only reachable from user space (via netlink) if they are * linked to a netdev at creation time. Following page pool "visibility" @@ -216,6 +218,7 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool, { struct net_devmem_dmabuf_binding *binding = pool->mp_priv; size_t inflight, refsz; + unsigned int napi_id; void *hdr;
hdr = genlmsg_iput(rsp, info); @@ -229,8 +232,10 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool, nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX, pool->slow.netdev->ifindex)) goto err_cancel; - if (pool->user.napi_id && - nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, pool->user.napi_id)) + + napi_id = pool->p.napi ? READ_ONCE(pool->p.napi->napi_id) : 0; + if (napi_id >= MIN_NAPI_ID && + nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, napi_id)) goto err_cancel;
inflight = page_pool_inflight(pool, false); @@ -319,8 +324,6 @@ int page_pool_list(struct page_pool *pool) if (pool->slow.netdev) { hlist_add_head(&pool->user.list, &pool->slow.netdev->page_pools); - pool->user.napi_id = pool->p.napi ? pool->p.napi->napi_id : 0; - netdev_nl_page_pool_event(pool, NETDEV_CMD_PAGE_POOL_ADD_NTF); }