CIFS: Fix incorrect max RFC1002 write size value

..the length field has only 17 bits.

Cc: <stable@kernel.org>
Acked-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/connect.c

@@ -2809,10 +2809,10 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 
 /*
  * When the server doesn't allow large posix writes, only allow a wsize of
- * 128k minus the size of the WRITE_AND_X header. That allows for a write up
+ * 2^17-1 minus the size of the WRITE_AND_X header. That allows for a write up
  * to the maximum size described by RFC1002.
  */
-#define CIFS_MAX_RFC1002_WSIZE (128 * 1024 - sizeof(WRITE_REQ) + 4)
+#define CIFS_MAX_RFC1002_WSIZE ((1<<17) - 1 - sizeof(WRITE_REQ) + 4)
 
 /*
  * The default wsize is 1M. find_get_pages seems to return a maximum of 256