cifs: add ignore_pend flag to cifs_call_async

The current code always ignores the max_pending limit. Have it instead
only optionally ignore the pending limit. For CIFSSMBEcho, we need to
ignore it to make sure they always can go out. For async reads, writes
and potentially other calls, we need to respect it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 67f59c7..16bcc07 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -343,13 +343,14 @@
  */
 int
 cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
-		unsigned int nvec, mid_callback_t *callback, void *cbdata)
+		unsigned int nvec, mid_callback_t *callback, void *cbdata,
+		bool ignore_pend)
 {
 	int rc;
 	struct mid_q_entry *mid;
 	struct smb_hdr *hdr = (struct smb_hdr *)iov[0].iov_base;
 
-	rc = wait_for_free_request(server, CIFS_ASYNC_OP);
+	rc = wait_for_free_request(server, ignore_pend ? CIFS_ASYNC_OP : 0);
 	if (rc)
 		return rc;