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author | J. Bruce Fields <bfields@redhat.com> | 2014-02-25 17:21:08 -0500 |
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committer | J. Bruce Fields <bfields@redhat.com> | 2014-03-28 21:24:49 -0400 |
commit | de4aee2e0a376fb272f44139150115a6dec1da95 (patch) | |
tree | 6eb394e6792d24331afde16e4704ce558b1882e1 /net/sunrpc/xdr.c | |
parent | 3f42d2c428c724212c5f4249daea97e254eb0546 (diff) | |
download | op-kernel-dev-de4aee2e0a376fb272f44139150115a6dec1da95.zip op-kernel-dev-de4aee2e0a376fb272f44139150115a6dec1da95.tar.gz |
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.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 1504bb1..dd97ba3 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) |