Commit ab1394ee authored by Chuck Lever's avatar Chuck Lever
Browse files

svcrdma: Refactor the RDMA Write path 



Refactor for subsequent changes.

Constify the xdr_buf argument to ensure the code here does not
modify it, and to enable callers to pass in a
"const struct xdr_buf *".

At the same time, rename the helper functions, which emit RDMA
Writes, not RDMA Sends, and add documenting comments.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 51bad8cc

net/sunrpc/xprtrdma/svc_rdma_rw.c

+35 −21
Original line number Diff line number Diff line
@@ -495,25 +495,40 @@ svc_rdma_build_writes(struct svc_rdma_write_info *info, 
	return -E2BIG;

}



/* Send one of an xdr_buf's kvecs by itself. To send a Reply

 * chunk, the whole RPC Reply is written back to the client.

 * This function writes either the head or tail of the xdr_buf

 * containing the Reply.

/**

 * svc_rdma_iov_write - Construct RDMA Writes from an iov

 * @info: pointer to write arguments

 * @iov: kvec to write

 *

 * Returns:

 *   On succes, returns zero

 *   %-E2BIG if the client-provided Write chunk is too small

 *   %-ENOMEM if a resource has been exhausted

 *   %-EIO if an rdma-rw error occurred

 */

static int svc_rdma_send_xdr_kvec(struct svc_rdma_write_info *info,

				  struct kvec *vec)

static int svc_rdma_iov_write(struct svc_rdma_write_info *info,

			      const struct kvec *iov)

{

	info->wi_base = vec->iov_base;

	info->wi_base = iov->iov_base;

	return svc_rdma_build_writes(info, svc_rdma_vec_to_sg,

				     vec->iov_len);

				     iov->iov_len);

}



/* Send an xdr_buf's page list by itself. A Write chunk is just

 * the page list. A Reply chunk is @xdr's head, page list, and

 * tail. This function is shared between the two types of chunk.

/**

 * svc_rdma_pages_write - Construct RDMA Writes from pages

 * @info: pointer to write arguments

 * @xdr: xdr_buf with pages to write

 * @offset: offset into the content of @xdr

 * @length: number of bytes to write

 *

 * Returns:

 *   On succes, returns zero

 *   %-E2BIG if the client-provided Write chunk is too small

 *   %-ENOMEM if a resource has been exhausted

 *   %-EIO if an rdma-rw error occurred

 */

static int svc_rdma_send_xdr_pagelist(struct svc_rdma_write_info *info,

				      struct xdr_buf *xdr,

static int svc_rdma_pages_write(struct svc_rdma_write_info *info,

				const struct xdr_buf *xdr,

				unsigned int offset,

				unsigned long length)

{
@@ -552,7 +567,7 @@ int svc_rdma_send_write_chunk(struct svcxprt_rdma *rdma, __be32 *wr_ch, 
	if (!info)

		return -ENOMEM;



	ret = svc_rdma_send_xdr_pagelist(info, xdr, offset, length);

	ret = svc_rdma_pages_write(info, xdr, offset, length);

	if (ret < 0)

		goto out_err;
@@ -592,7 +607,7 @@ int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma, 
	if (!info)

		return -ENOMEM;



	ret = svc_rdma_send_xdr_kvec(info, &xdr->head[0]);

	ret = svc_rdma_iov_write(info, &xdr->head[0]);

	if (ret < 0)

		goto out_err;

	consumed = xdr->head[0].iov_len;
@@ -601,8 +616,7 @@ int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma, 
	 * client did not provide Write chunks.

	 */

	if (!rctxt->rc_write_list && xdr->page_len) {

		ret = svc_rdma_send_xdr_pagelist(info, xdr,

						 xdr->head[0].iov_len,

		ret = svc_rdma_pages_write(info, xdr, xdr->head[0].iov_len,

					   xdr->page_len);

		if (ret < 0)

			goto out_err;
@@ -610,7 +624,7 @@ int svc_rdma_send_reply_chunk(struct svcxprt_rdma *rdma, 
	}



	if (xdr->tail[0].iov_len) {

		ret = svc_rdma_send_xdr_kvec(info, &xdr->tail[0]);

		ret = svc_rdma_iov_write(info, &xdr->tail[0]);

		if (ret < 0)

			goto out_err;

		consumed += xdr->tail[0].iov_len;