Make skb_frag_page() fail in the case where the frag is not backed by a page, and fix its relevent callers to handle this case.
Correctly handle skb_frag refcounting in the page_pool_iovs case.
Signed-off-by: Mina Almasry almasrymina@google.com
--- include/linux/skbuff.h | 42 +++++++++++++++++++++++++++++++++++------- net/core/gro.c | 2 +- net/core/skbuff.c | 3 +++ net/ipv4/tcp.c | 10 +++++++++- 4 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 97bfef071255..1fae276c1353 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -37,6 +37,8 @@ #endif #include <net/net_debug.h> #include <net/dropreason-core.h> +#include <net/page_pool/types.h> +#include <net/page_pool/helpers.h>
/** * DOC: skb checksums @@ -3402,15 +3404,38 @@ static inline void skb_frag_off_copy(skb_frag_t *fragto, fragto->bv_offset = fragfrom->bv_offset; }
+/* Returns true if the skb_frag contains a page_pool_iov. */ +static inline bool skb_frag_is_page_pool_iov(const skb_frag_t *frag) +{ + return page_is_page_pool_iov(frag->bv_page); +} + /** * skb_frag_page - retrieve the page referred to by a paged fragment * @frag: the paged fragment * - * Returns the &struct page associated with @frag. + * Returns 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) { - return frag->bv_page; + if (!page_is_page_pool_iov(frag->bv_page)) + return frag->bv_page; + + return NULL; +} + +/** + * skb_frag_page_pool_iov - retrieve the page_pool_iov referred to by fragment + * @frag: the fragment + * + * Returns the &struct page_pool_iov associated with @frag. Returns NULL if this + * frag has no associated page_pool_iov. + */ +static inline struct page_pool_iov * +skb_frag_page_pool_iov(const skb_frag_t *frag) +{ + return page_to_page_pool_iov(frag->bv_page); }
/** @@ -3421,7 +3446,7 @@ static inline struct page *skb_frag_page(const skb_frag_t *frag) */ static inline void __skb_frag_ref(skb_frag_t *frag) { - get_page(skb_frag_page(frag)); + page_pool_page_get_many(frag->bv_page, 1); }
/** @@ -3441,13 +3466,13 @@ bool napi_pp_put_page(struct page *page, bool napi_safe); static inline void napi_frag_unref(skb_frag_t *frag, bool recycle, bool napi_safe) { - struct page *page = skb_frag_page(frag); - #ifdef CONFIG_PAGE_POOL - if (recycle && napi_pp_put_page(page, napi_safe)) + if (recycle && napi_pp_put_page(frag->bv_page, napi_safe)) return; + page_pool_page_put_many(frag->bv_page, 1); +#else + put_page(skb_frag_page(frag)); #endif - put_page(page); }
/** @@ -3487,6 +3512,9 @@ static inline void skb_frag_unref(struct sk_buff *skb, int f) */ 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/net/core/gro.c b/net/core/gro.c index 0759277dc14e..42d7f6755f32 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -376,7 +376,7 @@ static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) NAPI_GRO_CB(skb)->frag0 = NULL; NAPI_GRO_CB(skb)->frag0_len = 0;
- if (!skb_headlen(skb) && pinfo->nr_frags && + if (!skb_headlen(skb) && 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); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index c52ddd6891d9..13eca4fd25e1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2994,6 +2994,9 @@ 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/tcp.c b/net/ipv4/tcp.c index a86d8200a1e8..23b29dc49271 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2155,6 +2155,9 @@ 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; @@ -4411,7 +4414,12 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, for (i = 0; i < shi->nr_frags; ++i) { const skb_frag_t *f = &shi->frags[i]; unsigned int offset = skb_frag_off(f); - struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); + struct page *page = skb_frag_page(f); + + if (WARN_ON_ONCE(!page)) + return 1; + + page += offset >> PAGE_SHIFT;
sg_set_page(&sg, page, skb_frag_size(f), offset_in_page(offset));