sunrpc: don't shorten buflen twice in xdr_shrink_pagelen

On Jan. 14, 2009, 2:50 +0200, andros@netapp.com wrote:
> From: Andy Adamson <andros@netapp.com>
>
> The buflen is reset for all cases at the end of xdr_shrink_pagelen.
> The data left in the tail after xdr_read_pages is not processed when the
> buflen is incorrectly set.

Note that in this case we also lose (len - tail->iov_len)
bytes from the buffered data in pages.
Reported-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/xdr.c

@@ -407,8 +407,7 @@ xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
 		if (tail->iov_len > len) {
 			copy = tail->iov_len - len;
 			memmove(p, tail->iov_base, copy);
-		} else
-			buf->buflen -= len;
+		}
 		/* Copy from the inlined pages into the tail */
 		copy = len;
 		if (copy > tail->iov_len)