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
---
Changes in v1: - Fix illegal_highdma() (Yunsheng). - Rework napi_pp_put_page() slightly to reduce code churn (Willem).
(cherry picked from commit e11c8035ed635e22aab224a89c48d93b5e881278)
also squashed assorted fixes --- include/linux/skbuff.h | 47 +++++++++++++++++++++++++++++++++++++----- net/core/dev.c | 3 ++- net/core/gro.c | 2 +- net/core/skbuff.c | 11 ++++++++++ net/ipv4/tcp.c | 3 +++ 5 files changed, 59 insertions(+), 7 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 1189d8d22da8..890fc2b94fc7 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3452,17 +3452,53 @@ 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 net_iov. */ +static inline bool skb_frag_is_net_iov(const skb_frag_t *frag) +{ + return netmem_is_net_iov(frag->bv_page); +} + +/** + * skb_frag_net_iov - retrieve the net_iov referred to by fragment + * @frag: the fragment + * + * Returns 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->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) { + if (skb_frag_is_net_iov(frag)) + return NULL; + return netmem_to_page(frag->bv_page); }
+/** + * skb_frag_netmem - retrieve the netmem referred to by a fragment + * @frag: the fragment + * + * Returns the &struct netmem associated with @frag. + */ +static inline struct netmem *skb_frag_netmem(const skb_frag_t *frag) +{ + return frag->bv_page; +} + /** * __skb_frag_ref - take an addition reference on a paged fragment. * @frag: the paged fragment @@ -3491,13 +3527,11 @@ bool napi_pp_put_page(struct netmem *netmem, 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_to_netmem(page), napi_safe)) + if (recycle && napi_pp_put_page(skb_frag_netmem(frag), napi_safe)) return; #endif - put_page(page); + put_page(skb_frag_page(frag)); }
/** @@ -3537,6 +3571,9 @@ 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/dev.c b/net/core/dev.c index 20ba528ef426..ad616b3c8e35 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3709,8 +3709,9 @@ 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 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 96f85543f1dc..671775bad5f9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1239,6 +1239,14 @@ 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 -= frag->bv_len; + if (!len) + break; + continue; + } + skb_frag_foreach_page(frag, skb_frag_off(frag), skb_frag_size(frag), p, p_off, p_len, copied) { @@ -3004,6 +3012,9 @@ 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 1d6b80145efb..82485af12cdc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2157,6 +2157,9 @@ 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;