Messages in this thread Patch in this message | | | From | Pavel Begunkov <> | Subject | [PATCH 11/14] skbuff: drop null check from skb_zcopy | Date | Tue, 11 Jan 2022 01:21:44 +0000 |
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skb_zcopy() is used all around the networkong code with many of calls sitting in generic not necessarily zerocopy paths. Many of callers don't ever pass a NULL skb, however a NULL check inside skb_zcopy() can't be optimised out. As with previous patch, move the check out of the helper to a few places where it's needed.
It removes a bunch of extra ifs in non-zerocopy paths, which is nice. E.g. before and after:
text data bss dec hex filename 8521472 0 0 8521472 820700 arch/x86/boot/bzImage 8521056 0 0 8521056 820560 arch/x86/boot/bzImage delta=416B
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- include/linux/skbuff.h | 2 +- net/core/dev.c | 2 +- net/core/skbuff.c | 3 ++- net/ipv4/ip_output.c | 7 +++++-- net/ipv4/tcp.c | 5 ++++- net/ipv6/ip6_output.c | 7 +++++-- 6 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8a7d0d03a100..7fd2b44aada0 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1469,7 +1469,7 @@ static inline struct skb_shared_hwtstamps *skb_hwtstamps(struct sk_buff *skb) static inline struct ubuf_info *skb_zcopy(struct sk_buff *skb) { - bool is_zcopy = skb && skb_shinfo(skb)->flags & SKBFL_ZEROCOPY_ENABLE; + bool is_zcopy = skb_shinfo(skb)->flags & SKBFL_ZEROCOPY_ENABLE; return is_zcopy ? skb_uarg(skb) : NULL; } diff --git a/net/core/dev.c b/net/core/dev.c index 83a4089990a0..877ebc0f72bd 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2239,7 +2239,7 @@ void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev) } out_unlock: if (pt_prev) { - if (!skb_orphan_frags_rx(skb2, GFP_ATOMIC)) + if (!skb2 || !skb_orphan_frags_rx(skb2, GFP_ATOMIC)) pt_prev->func(skb2, skb->dev, pt_prev, skb->dev); else kfree_skb(skb2); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e514a36bcffc..a9b8ac38dc1a 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -890,7 +890,8 @@ EXPORT_SYMBOL(skb_dump); */ void skb_tx_error(struct sk_buff *skb) { - skb_zcopy_clear(skb, true); + if (skb) + skb_zcopy_clear(skb, true); } EXPORT_SYMBOL(skb_tx_error); diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 87d4472545a5..b63f307cc5ab 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1001,10 +1001,13 @@ static int __ip_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) { - uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); + if (skb) + uarg = skb_zcopy(skb); + extra_uref = !uarg; /* only ref on new uarg */ + + uarg = msg_zerocopy_realloc(sk, length, uarg); if (!uarg) return -ENOBUFS; - extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ if (rt->dst.dev->features & NETIF_F_SG && csummode == CHECKSUM_PARTIAL) { paged = true; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3b75836db19b..f35e49ea08ec 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1188,7 +1188,10 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) { skb = tcp_write_queue_tail(sk); - uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb)); + if (skb) + uarg = skb_zcopy(skb); + + uarg = msg_zerocopy_realloc(sk, size, uarg); if (!uarg) { err = -ENOBUFS; goto out_err; diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 9881b61da493..41abe83c3419 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1513,10 +1513,13 @@ static int __ip6_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) { - uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); + if (skb) + uarg = skb_zcopy(skb); + extra_uref = !uarg; /* only ref on new uarg */ + + uarg = msg_zerocopy_realloc(sk, length, uarg); if (!uarg) return -ENOBUFS; - extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ if (rt->dst.dev->features & NETIF_F_SG && csummode == CHECKSUM_PARTIAL) { paged = true; -- 2.34.1
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