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>

4 files changed, 13 insertions, 11 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 59f69a6c5863..edeea060db44 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -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--;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ce7d3b021ffc..0543561da999 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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,
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 6c8b42299d9f..e48c37d74d77 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -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);
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 4e004424d400..5200aab0ca97 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -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.