[patch 002/114] net: Kill skb_truesize_check(), it only catches false-positives.

Greg KH
2009-03-14T01:20:31Z

[-- Attachment #1: net-kill-skb_truesize_check-it-only-catches-false-positives.patch --]
[-- Type: text/plain, Size: 2626 bytes --]

2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: David S. Miller <davem@davemloft.net>

[ Upstream commit 92a0acce186cde8ead56c6915d9479773673ea1a ]

A long time ago we had bugs, primarily in TCP, where we would modify
skb->truesize (for TSO queue collapsing) in ways which would corrupt
the socket memory accounting.

skb_truesize_check() was added in order to try and catch this error
more systematically.

However this debugging check has morphed into a Frankenstein of sorts
and these days it does nothing other than catch false-positives.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
include/linux/skbuff.h | 9 ---------
include/net/sock.h | 1 -
net/core/skbuff.c | 8 --------
net/core/sock.c | 1 -
4 files changed, 19 deletions(-)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -411,15 +411,6 @@ extern void skb_over_panic(struct
void *here);
extern void skb_under_panic(struct sk_buff *skb, int len,
void *here);
-extern void skb_truesize_bug(struct sk_buff *skb);
-
-static inline void skb_truesize_check(struct sk_buff *skb)
-{
- int len = sizeof(struct sk_buff) + skb->len;
-
- if (unlikely((int)skb->truesize < len))
- skb_truesize_bug(skb);
-}

extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
int getfrag(void *from, char *to, int offset,
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -784,7 +784,6 @@ static inline void sk_mem_uncharge(struc

static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)
{
- skb_truesize_check(skb);
sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
sk->sk_wmem_queued -= skb->truesize;
sk_mem_uncharge(sk, skb->truesize);
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -143,14 +143,6 @@ void skb_under_panic(struct sk_buff *skb
BUG();
}

-void skb_truesize_bug(struct sk_buff *skb)
-{
- WARN(net_ratelimit(), KERN_ERR "SKB BUG: Invalid truesize (%u) "
- "len=%u, sizeof(sk_buff)=%Zd\n",
- skb->truesize, skb->len, sizeof(struct sk_buff));
-}
-EXPORT_SYMBOL(skb_truesize_bug);
-
/* Allocate a new skbuff. We do this ourselves so we can fill in a few
* 'private' fields and also do memory statistics to find all the
* [BEEP] leaks.
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1137,7 +1137,6 @@ void sock_rfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;

- skb_truesize_check(skb);
atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
sk_mem_uncharge(skb->sk, skb->truesize);
}