cifs: wait_for_free_credits() make it possible to wait for >=1 credits

Change wait_for_free_credits() to allow waiting for >=1 credits instead of just
a single credit.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

fs/cifs/cifsglob.h

@@ -735,13 +735,13 @@ in_flight(struct TCP_Server_Info *server)
 }
 
 static inline bool
-has_credits(struct TCP_Server_Info *server, int *credits)
+has_credits(struct TCP_Server_Info *server, int *credits, int num_credits)
 {
 	int num;
 	spin_lock(&server->req_lock);
 	num = *credits;
 	spin_unlock(&server->req_lock);
-	return num > 0;
+	return num >= num_credits;
 }
 
 static inline void

fs/cifs/smb2ops.c

@@ -185,7 +185,7 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
 			spin_unlock(&server->req_lock);
 			cifs_num_waiters_inc(server);
 			rc = wait_event_killable(server->request_q,
-					has_credits(server, &server->credits));
+				has_credits(server, &server->credits, 1));
 			cifs_num_waiters_dec(server);
 			if (rc)
 				return rc;

fs/cifs/transport.c

@@ -486,8 +486,8 @@ smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 }
 
 static int
-wait_for_free_credits(struct TCP_Server_Info *server, const int flags,
-		      unsigned int *instance)
+wait_for_free_credits(struct TCP_Server_Info *server, const int num_credits,
+		      const int flags, unsigned int *instance)
 {
 	int rc;
 	int *credits;
@@ -513,11 +513,11 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int flags,
 	}
 
 	while (1) {
-		if (*credits <= 0) {
+		if (*credits < num_credits) {
 			spin_unlock(&server->req_lock);
 			cifs_num_waiters_inc(server);
 			rc = wait_event_killable(server->request_q,
-						 has_credits(server, credits));
+				has_credits(server, credits, num_credits));
 			cifs_num_waiters_dec(server);
 			if (rc)
 				return rc;
@@ -535,8 +535,8 @@ wait_for_free_credits(struct TCP_Server_Info *server, const int flags,
 
 			/* update # of requests on the wire to server */
 			if ((flags & CIFS_TIMEOUT_MASK) != CIFS_BLOCKING_OP) {
-				*credits -= 1;
-				server->in_flight++;
+				*credits -= num_credits;
+				server->in_flight += num_credits;
 				*instance = server->reconnect_instance;
 			}
 			spin_unlock(&server->req_lock);
@@ -550,7 +550,7 @@ static int
 wait_for_free_request(struct TCP_Server_Info *server, const int flags,
 		      unsigned int *instance)
 {
-	return wait_for_free_credits(server, flags, instance);
+	return wait_for_free_credits(server, 1, flags, instance);
 }
 
 int