| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <1386311490.30495.243.camel@edumazet-glaptop2.roam.corp.google.com>
Date: Thu, 05 Dec 2013 22:31:30 -0800
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>
Subject: [PATCH net-next] tcp: optimize some skb_shinfo(skb) uses
From: Eric Dumazet <edumazet@...gle.com>
Compiler doesn't know skb_shinfo(skb) pointer is usually constant.
By using a temporary variable, we help generating smaller code.
For example, tcp_init_nondata_skb() is inlined after this patch.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/tcp_output.c | 36 +++++++++++++++++++++---------------
1 file changed, 21 insertions(+), 15 deletions(-)
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 7820f3a7dd70..993da005e087 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -363,15 +363,17 @@ static inline void TCP_ECN_send(struct sock *sk, struct sk_buff *skb,
*/
static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum = 0;
TCP_SKB_CB(skb)->tcp_flags = flags;
TCP_SKB_CB(skb)->sacked = 0;
- skb_shinfo(skb)->gso_segs = 1;
- skb_shinfo(skb)->gso_size = 0;
- skb_shinfo(skb)->gso_type = 0;
+ shinfo->gso_segs = 1;
+ shinfo->gso_size = 0;
+ shinfo->gso_type = 0;
TCP_SKB_CB(skb)->seq = seq;
if (flags & (TCPHDR_SYN | TCPHDR_FIN))
@@ -986,6 +988,8 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb)
static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
unsigned int mss_now)
{
+ struct skb_shared_info *shinfo = skb_shinfo(skb);
+
/* Make sure we own this skb before messing gso_size/gso_segs */
WARN_ON_ONCE(skb_cloned(skb));
@@ -993,13 +997,13 @@ static void tcp_set_skb_tso_segs(const struct sock *sk, struct sk_buff *skb,
/* Avoid the costly divide in the normal
* non-TSO case.
*/
- skb_shinfo(skb)->gso_segs = 1;
- skb_shinfo(skb)->gso_size = 0;
- skb_shinfo(skb)->gso_type = 0;
+ shinfo->gso_segs = 1;
+ shinfo->gso_size = 0;
+ shinfo->gso_type = 0;
} else {
- skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
- skb_shinfo(skb)->gso_size = mss_now;
- skb_shinfo(skb)->gso_type = sk->sk_gso_type;
+ shinfo->gso_segs = DIV_ROUND_UP(skb->len, mss_now);
+ shinfo->gso_size = mss_now;
+ shinfo->gso_type = sk->sk_gso_type;
}
}
@@ -1146,6 +1150,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
*/
static void __pskb_trim_head(struct sk_buff *skb, int len)
{
+ struct skb_shared_info *shinfo;
int i, k, eat;
eat = min_t(int, len, skb_headlen(skb));
@@ -1157,23 +1162,24 @@ static void __pskb_trim_head(struct sk_buff *skb, int len)
}
eat = len;
k = 0;
- for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+ shinfo = skb_shinfo(skb);
+ for (i = 0; i < shinfo->nr_frags; i++) {
+ int size = skb_frag_size(&shinfo->frags[i]);
if (size <= eat) {
skb_frag_unref(skb, i);
eat -= size;
} else {
- skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
+ shinfo->frags[k] = shinfo->frags[i];
if (eat) {
- skb_shinfo(skb)->frags[k].page_offset += eat;
- skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
+ shinfo->frags[k].page_offset += eat;
+ skb_frag_size_sub(&shinfo->frags[k], eat);
eat = 0;
}
k++;
}
}
- skb_shinfo(skb)->nr_frags = k;
+ shinfo->nr_frags = k;
skb_reset_tail_pointer(skb);
skb->data_len -= len;
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists