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Subject[PATCH v3] cifs: Do not modify mid entry after submitting I/O in cifs_call_async
Date
From: Long Li <longli@microsoft.com>

In cifs_call_async, server may respond as soon as I/O is submitted. Because
mid entry is freed on the return path, it should not be modified after I/O
is submitted.

cifs_save_when_sent modifies the sent timestamp in mid entry, and should not
be called after I/O. Call it before I/O.

Signed-off-by: Long Li <longli@microsoft.com>
---
fs/cifs/transport.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 47a125e..f49b73f 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -536,11 +536,13 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
list_add_tail(&mid->qhead, &server->pending_mid_q);
spin_unlock(&GlobalMid_Lock);

-
+ /* Need to store the time in mid before calling I/O. For call_async,
+ * I/O response can come back and free the mid entry on another thread.
+ */
+ cifs_save_when_sent(mid);
cifs_in_send_inc(server);
rc = smb_send_rqst(server, rqst, flags);
cifs_in_send_dec(server);
- cifs_save_when_sent(mid);

if (rc < 0) {
server->sequence_number -= 2;
--
2.7.4
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