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tcp: replace hard coded GFP_KERNEL with sk_allocation

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This fixed a lockdep warning which appeared when doing stress
memory tests over NFS:

	inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.

	page reclaim => nfs_writepage => tcp_sendmsg => lock sk_lock

	mount_root => nfs_root_data => tcp_close => lock sk_lock =>
			tcp_send_fin => alloc_skb_fclone => page reclaim

David raised a concern that if the allocation fails in tcp_send_fin(), and it's
GFP_ATOMIC, we are going to yield() (which sleeps) and loop endlessly waiting
for the allocation to succeed.

But fact is, the original GFP_KERNEL also sleeps. GFP_ATOMIC+yield() looks
weird, but it is no worse the implicit sleep inside GFP_KERNEL. Both could
loop endlessly under memory pressure.

CC: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
CC: David S. Miller <davem@davemloft.net>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wu Fengguang
2009-09-02 23:45:45 -07:00
committed by David S. Miller
parent 05c6a8d7a7
commit aa1330766c
6 changed files with 15 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/ipv4/tcp.c
+5 -5
View File
@@ -1839,7 +1839,7 @@ void tcp_close(struct sock *sk, long timeout)
/* Unread data was tossed, zap the connection. */
NET_INC_STATS_USER(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_KERNEL);
tcp_send_active_reset(sk, sk->sk_allocation);
} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
/* Check zero linger _after_ checking for unread data. */
sk->sk_prot->disconnect(sk, 0);
@@ -2658,7 +2658,7 @@ void tcp_free_md5sig_pool(void)
EXPORT_SYMBOL(tcp_free_md5sig_pool);
static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(struct sock *sk)
{
int cpu;
struct tcp_md5sig_pool **pool;
@@ -2671,7 +2671,7 @@ static struct tcp_md5sig_pool **__tcp_alloc_md5sig_pool(void)
struct tcp_md5sig_pool *p;
struct crypto_hash *hash;
p = kzalloc(sizeof(*p), GFP_KERNEL);
p = kzalloc(sizeof(*p), sk->sk_allocation);
if (!p)
goto out_free;
*per_cpu_ptr(pool, cpu) = p;
@@ -2688,7 +2688,7 @@ out_free:
return NULL;
}
struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void)
struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *sk)
{
struct tcp_md5sig_pool **pool;
int alloc = 0;
@@ -2709,7 +2709,7 @@ retry:
if (alloc) {
/* we cannot hold spinlock here because this may sleep. */
struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();
struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool(sk);
spin_lock_bh(&tcp_md5sig_pool_lock);
if (!p) {
tcp_md5sig_users--;