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authorJ. Bruce Fields <bfields@redhat.com>2014-02-26 02:21:08 +0400
committerJ. Bruce Fields <bfields@redhat.com>2014-03-29 05:24:49 +0400
commitde4aee2e0a376fb272f44139150115a6dec1da95 (patch)
tree6eb394e6792d24331afde16e4704ce558b1882e1 /net/sunrpc/xdr.c
parent3f42d2c428c724212c5f4249daea97e254eb0546 (diff)
downloadlinux-de4aee2e0a376fb272f44139150115a6dec1da95.tar.xz
rpc: Allow xdr_buf_subsegment to operate in-place
Allow xdr_buf_subsegment(&buf, &buf, base, len) to modify an xdr_buf in-place. Also, none of the callers need the iov_base of head or tail to be zeroed out. Also add documentation. (As it turns out, I'm not really using this new guarantee, but it seems a simple way to make this function a bit more robust.) Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net/sunrpc/xdr.c')
-rw-r--r--net/sunrpc/xdr.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 1504bb11e4f3..dd97ba3c4456 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -833,8 +833,20 @@ xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
}
EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
-/* Sets subbuf to the portion of buf of length len beginning base bytes
- * from the start of buf. Returns -1 if base of length are out of bounds. */
+/**
+ * xdr_buf_subsegment - set subbuf to a portion of buf
+ * @buf: an xdr buffer
+ * @subbuf: the result buffer
+ * @base: beginning of range in bytes
+ * @len: length of range in bytes
+ *
+ * sets @subbuf to an xdr buffer representing the portion of @buf of
+ * length @len starting at offset @base.
+ *
+ * @buf and @subbuf may be pointers to the same struct xdr_buf.
+ *
+ * Returns -1 if base of length are out of bounds.
+ */
int
xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
unsigned int base, unsigned int len)
@@ -847,9 +859,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
len -= subbuf->head[0].iov_len;
base = 0;
} else {
- subbuf->head[0].iov_base = NULL;
- subbuf->head[0].iov_len = 0;
base -= buf->head[0].iov_len;
+ subbuf->head[0].iov_len = 0;
}
if (base < buf->page_len) {
@@ -871,9 +882,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
len -= subbuf->tail[0].iov_len;
base = 0;
} else {
- subbuf->tail[0].iov_base = NULL;
- subbuf->tail[0].iov_len = 0;
base -= buf->tail[0].iov_len;
+ subbuf->tail[0].iov_len = 0;
}
if (base || len)