On 11/05, Mina Almasry wrote:
Implement a memory provider that allocates dmabuf devmem page_pool_iovs.
Support of PP_FLAG_DMA_MAP and PP_FLAG_DMA_SYNC_DEV is omitted for simplicity.
The provider receives a reference to the struct netdev_dmabuf_binding via the pool->mp_priv pointer. The driver needs to set this pointer for the provider in the page_pool_params.
The provider obtains a reference on the netdev_dmabuf_binding which guarantees the binding and the underlying mapping remains alive until the provider 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
include/net/page_pool/helpers.h | 40 +++++++++++++++++ include/net/page_pool/types.h | 10 +++++ net/core/page_pool.c | 76 +++++++++++++++++++++++++++++++++ 3 files changed, 126 insertions(+)
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 78cbb040af94..b93243c2a640 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -53,6 +53,7 @@ #define _NET_PAGE_POOL_HELPERS_H #include <net/page_pool/types.h> +#include <net/net_debug.h> #ifdef CONFIG_PAGE_POOL_STATS int page_pool_ethtool_stats_get_count(void); @@ -111,6 +112,45 @@ page_pool_iov_binding(const struct page_pool_iov *ppiov) return page_pool_iov_owner(ppiov)->binding; } +static inline int page_pool_iov_refcount(const struct page_pool_iov *ppiov) +{
- return refcount_read(&ppiov->refcount);
+}
+static inline void page_pool_iov_get_many(struct page_pool_iov *ppiov,
unsigned int count)+{
- refcount_add(count, &ppiov->refcount);
+}
+void __page_pool_iov_free(struct page_pool_iov *ppiov);
+static inline void page_pool_iov_put_many(struct page_pool_iov *ppiov,
unsigned int count)+{
- if (!refcount_sub_and_test(count, &ppiov->refcount))
return;- __page_pool_iov_free(ppiov);
+}
+/* page pool mm helpers */
+static inline bool page_is_page_pool_iov(const struct page *page) +{
- return (unsigned long)page & PP_DEVMEM;
+}
Speaking of bpf: one thing that might be problematic with this PP_DEVMEM bit is that it will make debugging with bpftrace a bit (more) complicated. If somebody were trying to get to that page_pool_iov from the frags, they will have to do the equivalent of page_is_page_pool_iov, but probably not a big deal? (thinking out loud)