[PATCH v3 17/19] cifs: discard functions should not return failure

[nspmangalore@gmail.com]

From: Shyam Prasad N <sprasad@microsoft.com>

If discard functions for readv and query_dir return error, the
callback functions can be skipped. This can end up with hung
syscalls due to the completion functions not getting called.

This change ensures that both these discard functions return
success even when discard from socket returned error. This
ensures that at least after the mid for the response is found,
the callback doesn't get skipped, and we do not leave syscalls
waiting.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
---
 fs/smb/client/transport.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 1e9e6f3f9a06f..85fa5751781a8 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -1137,13 +1137,13 @@ static int
 __cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		     bool malformed)
 {
-	int length;
-
-	length = cifs_discard_remaining_data(server);
+	cifs_discard_remaining_data(server);
 	dequeue_mid(server, mid, malformed);
 	mid->resp_buf = server->smallbuf;
 	server->smallbuf = NULL;
-	return length;
+
+	/* Once the mid is dequeued, the callback must run to terminate the subreq. */
+	return 0;
 }
 
 static int
@@ -1158,13 +1158,13 @@ static int
 cifs_query_dir_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 		      bool malformed)
 {
-	int length;
-
-	length = cifs_discard_remaining_data(server);
+	cifs_discard_remaining_data(server);
 	dequeue_mid(server, mid, malformed);
 	mid->resp_buf = server->smallbuf;
 	server->smallbuf = NULL;
-	return length;
+
+	/* Once the mid is dequeued, the callback must run to complete qd_io->done. */
+	return 0;
 }
 
 /*
-- 
2.43.0