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authorSachin Prabhu <sprabhu@redhat.com>2012-07-11 12:28:05 +0100
committerSteve French <smfrench@gmail.com>2012-07-16 23:57:02 -0500
commitffc61ccbb96809df8d97ed609ac86b509eaf9056 (patch)
tree6f97d985c640d7881aeb6ae888359e1c73213a1a /fs/cifs/transport.c
parent055c9fa8874fa7261eec7a268366565db84af474 (diff)
Initialise mid_q_entry before putting it on the pending queue
A user reported a crash in cifs_demultiplex_thread() caused by an incorrectly set mid_q_entry->callback() function. It appears that the callback assignment made in cifs_call_async() was not flushed back to memory suggesting that a memory barrier was required here. Changing the code to make sure that the mid_q_entry structure was completely initialised before it was added to the pending queue fixes the problem. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/transport.c')
-rw-r--r--fs/cifs/transport.c26
1 files changed, 14 insertions, 12 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 3097ee58fd7d..f25d4ea14be4 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -365,16 +365,14 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov,
if (mid == NULL)
return -ENOMEM;
- /* put it on the pending_mid_q */
- spin_lock(&GlobalMid_Lock);
- list_add_tail(&mid->qhead, &server->pending_mid_q);
- spin_unlock(&GlobalMid_Lock);
-
rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
- if (rc)
- delete_mid(mid);
+ if (rc) {
+ DeleteMidQEntry(mid);
+ return rc;
+ }
+
*ret_mid = mid;
- return rc;
+ return 0;
}
/*
@@ -407,17 +405,21 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
mid->callback_data = cbdata;
mid->mid_state = MID_REQUEST_SUBMITTED;
+ /* put it on the pending_mid_q */
+ spin_lock(&GlobalMid_Lock);
+ list_add_tail(&mid->qhead, &server->pending_mid_q);
+ spin_unlock(&GlobalMid_Lock);
+
+
cifs_in_send_inc(server);
rc = smb_sendv(server, iov, nvec);
cifs_in_send_dec(server);
cifs_save_when_sent(mid);
mutex_unlock(&server->srv_mutex);
- if (rc)
- goto out_err;
+ if (rc == 0)
+ return 0;
- return rc;
-out_err:
delete_mid(mid);
add_credits(server, 1);
wake_up(&server->request_q);