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Commit de4aee2e authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

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: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 3f42d2c4

net/sunrpc/xdr.c

+16 −6
Original line number Original line Diff line number Diff line
@@ -833,8 +833,20 @@ xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf) 
}

}

EXPORT_SYMBOL_GPL(xdr_buf_from_iov);

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

int

xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,

xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,

			unsigned int base, unsigned int len)

			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;

		len -= subbuf->head[0].iov_len;

		base = 0;

		base = 0;

	} else {

	} else {

		subbuf->head[0].iov_base = NULL;

		subbuf->head[0].iov_len = 0;

		base -= buf->head[0].iov_len;

		base -= buf->head[0].iov_len;

		subbuf->head[0].iov_len = 0;

	}

	}





	if (base < buf->page_len) {

	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;

		len -= subbuf->tail[0].iov_len;

		base = 0;

		base = 0;

	} else {

	} else {

		subbuf->tail[0].iov_base = NULL;

		subbuf->tail[0].iov_len = 0;

		base -= buf->tail[0].iov_len;

		base -= buf->tail[0].iov_len;

		subbuf->tail[0].iov_len = 0;

	}

	}





	if (base || len)

	if (base || len)