From: Long Li <longli@exchange.microsoft.com>
To: Steve French <sfrench@samba.org>,
linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
linux-kernel@vger.kernel.org
Cc: Long Li <longli@microsoft.com>
Subject: [PATCH v4] cifs: Do not modify mid entry after submitting I/O in cifs_call_async
Date: Wed, 28 Jun 2017 15:55:55 -0700 [thread overview]
Message-ID: <1498690555-8454-1-git-send-email-longli@exchange.microsoft.com> (raw)
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>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
---
fs/cifs/transport.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 47a125e..7efbab0 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -536,11 +536,14 @@ 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 may 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
next reply other threads:[~2017-06-28 22:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-28 22:55 Long Li [this message]
2017-06-29 15:56 ` [PATCH v4] cifs: Do not modify mid entry after submitting I/O in cifs_call_async Steve French
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