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tcp: replace hard coded GFP_KERNEL with sk_allocation 

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/tcp.h
View File

@ -1186,7 +1186,7 @@ extern int tcp_v4_md5_do_del(struct sock *sk,
#define tcp_twsk_md5_key(twsk) NULL
#endif
extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void);
extern struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(struct sock *);
extern void tcp_free_md5sig_pool(void);
extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu);

10
net/ipv4/tcp.c
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--;

7
net/ipv4/tcp_ipv4.c
View File

@ -886,7 +886,7 @@ int tcp_v4_md5_do_add(struct sock *sk, __be32 addr,
}
sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
}
if (tcp_alloc_md5sig_pool() == NULL) {
if (tcp_alloc_md5sig_pool(sk) == NULL) {
kfree(newkey);
return -ENOMEM;
}
@ -1007,8 +1007,9 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
if (!tcp_sk(sk)->md5sig_info) {
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_md5sig_info *p = kzalloc(sizeof(*p), GFP_KERNEL);
struct tcp_md5sig_info *p;
p = kzalloc(sizeof(*p), sk->sk_allocation);
if (!p)
return -EINVAL;
@ -1016,7 +1017,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
}
newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
newkey = kmemdup(cmd.tcpm_key, cmd.tcpm_keylen, sk->sk_allocation);
if (!newkey)
return -ENOMEM;
return tcp_v4_md5_do_add(sk, sin->sin_addr.s_addr,

2
net/ipv4/tcp_minisocks.c
View File

@ -322,7 +322,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
if (key != NULL) {
memcpy(&tcptw->tw_md5_key, key->key, key->keylen);
tcptw->tw_md5_keylen = key->keylen;
if (tcp_alloc_md5sig_pool() == NULL)
if (tcp_alloc_md5sig_pool(sk) == NULL)
BUG();
}
} while (0);

5
net/ipv4/tcp_output.c
View File

@ -2135,7 +2135,8 @@ void tcp_send_fin(struct sock *sk)
} else {
/* Socket is locked, keep trying until memory is available. */
for (;;) {
skb = alloc_skb_fclone(MAX_TCP_HEADER, GFP_KERNEL);
skb = alloc_skb_fclone(MAX_TCP_HEADER,
sk->sk_allocation);
if (skb)
break;
yield();
@ -2388,7 +2389,7 @@ int tcp_connect(struct sock *sk)
sk->sk_wmem_queued += buff->truesize;
sk_mem_charge(sk, buff->truesize);
tp->packets_out += tcp_skb_pcount(buff);
tcp_transmit_skb(sk, buff, 1, GFP_KERNEL);
tcp_transmit_skb(sk, buff, 1, sk->sk_allocation);
/* We change tp->snd_nxt after the tcp_transmit_skb() call
* in order to make this packet get counted in tcpOutSegs.

2
net/ipv6/tcp_ipv6.c
View File

@ -591,7 +591,7 @@ static int tcp_v6_md5_do_add(struct sock *sk, struct in6_addr *peer,
}
sk->sk_route_caps &= ~NETIF_F_GSO_MASK;
}
if (tcp_alloc_md5sig_pool() == NULL) {
if (tcp_alloc_md5sig_pool(sk) == NULL) {
kfree(newkey);
return -ENOMEM;
}