cifs: move mid finding into separate routine

Begin breaking up find_cifs_mid into smaller pieces. The parts that
coalesce T2 responses don't really need to be done under the
GlobalMid_lock anyway. Create a new function that just finds the
mid on the list, and then later takes it off the list if the entire
response has been received.

Reviewed-and-Tested-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 5308bc6e12481b411af3b448ef0505ccc352cbce..0f69b311d3fc8a9893b0cb5541059ff32754ac30 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -542,61 +542,80 @@ is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 }
 
 static struct mid_q_entry *
-find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
-             int *length, bool is_large_buf, bool *is_multi_rsp, char **bigbuf)
+find_mid(struct TCP_Server_Info *server, struct smb_hdr *buf)
 {
-       struct mid_q_entry *mid = NULL, *tmp_mid, *ret = NULL;
+       struct mid_q_entry *mid;
 
        spin_lock(&GlobalMid_Lock);
-       list_for_each_entry_safe(mid, tmp_mid, &server->pending_mid_q, qhead) {
-               if (mid->mid != buf->Mid ||
-                   mid->midState != MID_REQUEST_SUBMITTED ||
-                   mid->command != buf->Command)
-                       continue;
-
-               if (*length == 0 && check2ndT2(buf) > 0) {
-                       /* We have a multipart transact2 resp */
-                       *is_multi_rsp = true;
-                       if (mid->resp_buf) {
-                               /* merge response - fix up 1st*/
-                               *length = coalesce_t2(buf, mid->resp_buf);
-                               if (*length > 0) {
-                                       *length = 0;
-                                       mid->multiRsp = true;
-                                       break;
-                               }
-                               /* All parts received or packet is malformed. */
-                               mid->multiEnd = true;
-                               goto multi_t2_fnd;
-                       }
-                       if (!is_large_buf) {
-                               /*FIXME: switch to already allocated largebuf?*/
-                               cERROR(1, "1st trans2 resp needs bigbuf");
-                       } else {
-                               /* Have first buffer */
-                               mid->resp_buf = buf;
-                               mid->largeBuf = true;
-                               *bigbuf = NULL;
-                       }
-                       break;
+       list_for_each_entry(mid, &server->pending_mid_q, qhead) {
+               if (mid->mid == buf->Mid &&
+                   mid->midState == MID_REQUEST_SUBMITTED &&
+                   mid->command == buf->Command) {
+                       spin_unlock(&GlobalMid_Lock);
+                       return mid;
                }
-               mid->resp_buf = buf;
-               mid->largeBuf = is_large_buf;
-multi_t2_fnd:
-               if (*length == 0)
-                       mid->midState = MID_RESPONSE_RECEIVED;
-               else
-                       mid->midState = MID_RESPONSE_MALFORMED;
+       }
+       spin_unlock(&GlobalMid_Lock);
+       return NULL;
+}
+
+static void
+dequeue_mid(struct mid_q_entry *mid, int malformed)
+{
 #ifdef CONFIG_CIFS_STATS2
-               mid->when_received = jiffies;
+       mid->when_received = jiffies;
 #endif
-               list_del_init(&mid->qhead);
-               ret = mid;
-               break;
-       }
+       spin_lock(&GlobalMid_Lock);
+       if (!malformed)
+               mid->midState = MID_RESPONSE_RECEIVED;
+       else
+               mid->midState = MID_RESPONSE_MALFORMED;
+       list_del_init(&mid->qhead);
        spin_unlock(&GlobalMid_Lock);
+}
 
-       return ret;
+static struct mid_q_entry *
+find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
+             int *malformed, bool is_large_buf, bool *is_multi_rsp,
+             char **bigbuf)
+{
+       struct mid_q_entry *mid = NULL;
+
+       mid = find_mid(server, buf);
+       if (!mid)
+               return mid;
+
+       if (*malformed == 0 && check2ndT2(buf) > 0) {
+               /* We have a multipart transact2 resp */
+               *is_multi_rsp = true;
+               if (mid->resp_buf) {
+                       /* merge response - fix up 1st*/
+                       *malformed = coalesce_t2(buf, mid->resp_buf);
+                       if (*malformed > 0) {
+                               *malformed = 0;
+                               mid->multiRsp = true;
+                               return NULL;
+                       }
+                       /* All parts received or packet is malformed. */
+                       mid->multiEnd = true;
+                       goto multi_t2_fnd;
+               }
+               if (!is_large_buf) {
+                       /*FIXME: switch to already allocated largebuf?*/
+                       cERROR(1, "1st trans2 resp needs bigbuf");
+               } else {
+                       /* Have first buffer */
+                       mid->resp_buf = buf;
+                       mid->largeBuf = true;
+                       *bigbuf = NULL;
+               }
+               return mid;
+       }
+       mid->resp_buf = buf;
+       mid->largeBuf = is_large_buf;
+multi_t2_fnd:
+       dequeue_mid(mid, *malformed);
+       return mid;
 }
 
 static void clean_demultiplex_info(struct TCP_Server_Info *server)