UPSTREAM next (v3.11): af_unix: use freezable blocking calls in read
Colin Cross [Mon, 6 May 2013 23:50:21 +0000 (23:50 +0000)]
Avoid waking up every thread sleeping in read call on an AF_UNIX
socket during suspend and resume by calling a freezable blocking
call.  Previous patches modified the freezer to avoid sending
wakeups to threads that are blocked in freezable blocking calls.

This call was selected to be converted to a freezable call because
it doesn't hold any locks or release any resources when interrupted
that might be needed by another freezing task or a kernel driver
during suspend, and is a common site where idle userspace tasks are
blocked.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 2b15af6f953012aac49984ead3f8ec744d941540)
Change-Id: Ia8fc03aab1b38141e8e011f965bdc96bf39f89e9
Reviewed-on: http://git-master/r/228701
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

net/unix/af_unix.c

index 826e099..c4ce243 100644 (file)
 #include <linux/mount.h>
 #include <net/checksum.h>
 #include <linux/security.h>
+#include <linux/freezer.h>
 
 struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];
 EXPORT_SYMBOL_GPL(unix_socket_table);
@@ -1879,7 +1880,7 @@ static long unix_stream_data_wait(struct sock *sk, long timeo,
 
                set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
                unix_state_unlock(sk);
-               timeo = schedule_timeout(timeo);
+               timeo = freezable_schedule_timeout(timeo);
                unix_state_lock(sk);
                clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
        }