netdev - [PATCH net-next] net: allow better page reuse in splice(sock -> pipe)

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Date:	Thu, 19 Apr 2012 21:38:17 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	David Miller <davem@...emloft.net>
Cc:	netdev <netdev@...r.kernel.org>
Subject: [PATCH net-next] net: allow better page reuse in splice(sock ->
 pipe)

From: Eric Dumazet <edumazet@...gle.com>

splice() from socket to pipe needs linear_to_page() helper to transfert
skb header to part of page.

We can reset the offset in the current sk->sk_sndmsg_page if we are the
last user of the page.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/core/skbuff.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 43c490d..bf257de 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1565,6 +1565,9 @@ new_page:
 	} else {
 		unsigned int mlen;
 
+		/* If we are the only user of the page, we can reset offset */
+		if (page_count(p) == 1)
+			sk->sk_sndmsg_off = 0;
 		off = sk->sk_sndmsg_off;
 		mlen = PAGE_SIZE - off;
 		if (mlen < 64 && mlen < *len) {


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