SUNRPC: Remove xdr_buf_trim()

The key action of xdr_buf_trim() is that it shortens buf->len, the
length of the xdr_buf's content. The other actions -- shortening the
head, pages, and tail components -- are actually not necessary. In
particular, changing the size of those components can corrupt the
RPC message contained in the buffer. This is an accident waiting to
happen rather than a current bug, as far as we know.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 0 insertions, 41 deletions

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 5f0aa53fa4ae..4bce61978062 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1139,47 +1139,6 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
 }
 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
 
-/**
- * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
- * @buf: buf to be trimmed
- * @len: number of bytes to reduce "buf" by
- *
- * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
- * that it's possible that we'll trim less than that amount if the xdr_buf is
- * too small, or if (for instance) it's all in the head and the parser has
- * already read too far into it.
- */
-void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
-{
-	size_t cur;
-	unsigned int trim = len;
-
-	if (buf->tail[0].iov_len) {
-		cur = min_t(size_t, buf->tail[0].iov_len, trim);
-		buf->tail[0].iov_len -= cur;
-		trim -= cur;
-		if (!trim)
-			goto fix_len;
-	}
-
-	if (buf->page_len) {
-		cur = min_t(unsigned int, buf->page_len, trim);
-		buf->page_len -= cur;
-		trim -= cur;
-		if (!trim)
-			goto fix_len;
-	}
-
-	if (buf->head[0].iov_len) {
-		cur = min_t(size_t, buf->head[0].iov_len, trim);
-		buf->head[0].iov_len -= cur;
-		trim -= cur;
-	}
-fix_len:
-	buf->len -= (len - trim);
-}
-EXPORT_SYMBOL_GPL(xdr_buf_trim);
-
 static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
 {
 	unsigned int this_len;