smb3: fix incorrect number of credits when ioctl MaxOutputResponse > 64K

We were not checking to see if ioctl requests asked for more than
64K (ie when CIFSMaxBufSize was > 64K) so when setting larger
CIFSMaxBufSize then ioctls would fail with invalid parameter errors.
When requests ask for more than 64K in MaxOutputResponse then we
need to ask for more than 1 credit.

Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>

fs/cifs/smb2pdu.c

@@ -2938,7 +2938,7 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 	 * response size smaller.
 	 */
 	req->MaxOutputResponse = cpu_to_le32(max_response_size);
-
+	req->sync_hdr.CreditCharge = cpu_to_le16(DIV_ROUND_UP(max_response_size, SMB2_MAX_BUFFER_SIZE));
 	if (is_fsctl)
 		req->Flags = cpu_to_le32(SMB2_0_IOCTL_IS_FSCTL);
 	else