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authorRainer Weikusat <rweikusat@mobileactivedefense.com>2015-12-16 20:09:25 +0000
committerDavid S. Miller <davem@davemloft.net>2015-12-17 15:33:47 -0500
commit3822b5c2fc62e3de8a0f33806ff279fb7df92432 (patch)
treeb820d7ac997e8b1d4c2505416c7ef7a8c55b74c1 /net
parent3036facbb7be3a169e35be3b271162b0fa564a2d (diff)
af_unix: Revert 'lock_interruptible' in stream receive code
With b3ca9b02b00704053a38bfe4c31dbbb9c13595d0, the AF_UNIX SOCK_STREAM receive code was changed from using mutex_lock(&u->readlock) to mutex_lock_interruptible(&u->readlock) to prevent signals from being delayed for an indefinite time if a thread sleeping on the mutex happened to be selected for handling the signal. But this was never a problem with the stream receive code (as opposed to its datagram counterpart) as that never went to sleep waiting for new messages with the mutex held and thus, wouldn't cause secondary readers to block on the mutex waiting for the sleeping primary reader. As the interruptible locking makes the code more complicated in exchange for no benefit, change it back to using mutex_lock. Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/unix/af_unix.c13
1 files changed, 3 insertions, 10 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 45aebd966978..a4631477cedf 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2256,14 +2256,7 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
/* Lock the socket to prevent queue disordering
* while sleeps in memcpy_tomsg
*/
- err = mutex_lock_interruptible(&u->readlock);
- if (unlikely(err)) {
- /* recvmsg() in non blocking mode is supposed to return -EAGAIN
- * sk_rcvtimeo is not honored by mutex_lock_interruptible()
- */
- err = noblock ? -EAGAIN : -ERESTARTSYS;
- goto out;
- }
+ mutex_lock(&u->readlock);
if (flags & MSG_PEEK)
skip = sk_peek_offset(sk, flags);
@@ -2307,12 +2300,12 @@ again:
timeo = unix_stream_data_wait(sk, timeo, last,
last_len);
- if (signal_pending(current) ||
- mutex_lock_interruptible(&u->readlock)) {
+ if (signal_pending(current)) {
err = sock_intr_errno(timeo);
goto out;
}
+ mutex_lock(&u->readlock);
continue;
unlock:
unix_state_unlock(sk);