diff mbox series

[11/14] skbuff: drop null check from skb_zcopy

Message ID cc77c4de5509d1b78afbff5c640f45eceb05617a.1641863490.git.asml.silence@gmail.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series udp optimisation | expand

Checks

Context Check Description
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 6057 this patch: 6057
netdev/cc_maintainers warning 2 maintainers not CCed: keescook@chromium.org alobakin@pm.me
netdev/build_clang success Errors and warnings before: 1009 this patch: 1009
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 6208 this patch: 6208
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 66 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply, async

Commit Message

Pavel Begunkov Jan. 11, 2022, 1:21 a.m. UTC 
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 mbox series

Patch

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;