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svcrdma: Support multiple Write chunks in svc_rdma_map_reply_msg() 

Refactor: svc_rdma_map_reply_msg() is restructured to DMA map only
the parts of rq_res that do not contain a result payload.

This change has been tested to confirm that it does not cause a
regression in the no Write chunk and single Write chunk cases.
Multiple Write chunks have not been tested.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-03-09 13:29:27 -04:00
parent 9d0b09d5ef
commit 2371bcc056
3 changed files with 100 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/sunrpc/svc_rdma.h
View File

@ -213,7 +213,7 @@ extern int svc_rdma_send(struct svcxprt_rdma *rdma,
extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_recv_ctxt *rctxt,
struct xdr_buf *xdr);
const struct xdr_buf *xdr);
extern void svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
struct svc_rdma_recv_ctxt *rctxt,

1
include/trace/events/rpcrdma.h
View File

@ -1687,6 +1687,7 @@ DECLARE_EVENT_CLASS(svcrdma_dma_map_class,
TP_ARGS(rdma, dma_addr, length))
DEFINE_SVC_DMA_EVENT(dma_map_page);
DEFINE_SVC_DMA_EVENT(dma_map_err);
DEFINE_SVC_DMA_EVENT(dma_unmap_page);
TRACE_EVENT(svcrdma_dma_map_rw_err,

174
net/sunrpc/xprtrdma/svc_rdma_sendto.c
View File

@ -496,39 +496,111 @@ svc_rdma_encode_reply_chunk(struct svc_rdma_recv_ctxt *rctxt,
return svc_rdma_encode_write_chunk(sctxt, chunk);
}
static int svc_rdma_dma_map_page(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt,
struct page *page,
unsigned long offset,
unsigned int len)
struct svc_rdma_map_data {
struct svcxprt_rdma *md_rdma;
struct svc_rdma_send_ctxt *md_ctxt;
};
/**
* svc_rdma_page_dma_map - DMA map one page
* @data: pointer to arguments
* @page: struct page to DMA map
* @offset: offset into the page
* @len: number of bytes to map
*
* Returns:
* %0 if DMA mapping was successful
* %-EIO if the page cannot be DMA mapped
*/
static int svc_rdma_page_dma_map(void *data, struct page *page,
unsigned long offset, unsigned int len)
{
struct svc_rdma_map_data *args = data;
struct svcxprt_rdma *rdma = args->md_rdma;
struct svc_rdma_send_ctxt *ctxt = args->md_ctxt;
struct ib_device *dev = rdma->sc_cm_id->device;
dma_addr_t dma_addr;
++ctxt->sc_cur_sge_no;
dma_addr = ib_dma_map_page(dev, page, offset, len, DMA_TO_DEVICE);
trace_svcrdma_dma_map_page(rdma, dma_addr, len);
if (ib_dma_mapping_error(dev, dma_addr))
goto out_maperr;
trace_svcrdma_dma_map_page(rdma, dma_addr, len);
ctxt->sc_sges[ctxt->sc_cur_sge_no].addr = dma_addr;
ctxt->sc_sges[ctxt->sc_cur_sge_no].length = len;
ctxt->sc_send_wr.num_sge++;
return 0;
out_maperr:
trace_svcrdma_dma_map_err(rdma, dma_addr, len);
return -EIO;
}
/* ib_dma_map_page() is used here because svc_rdma_dma_unmap()
/**
* svc_rdma_iov_dma_map - DMA map an iovec
* @data: pointer to arguments
* @iov: kvec to DMA map
*
* ib_dma_map_page() is used here because svc_rdma_dma_unmap()
* handles DMA-unmap and it uses ib_dma_unmap_page() exclusively.
*
* Returns:
* %0 if DMA mapping was successful
* %-EIO if the iovec cannot be DMA mapped
*/
static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt,
unsigned char *base,
unsigned int len)
static int svc_rdma_iov_dma_map(void *data, const struct kvec *iov)
{
return svc_rdma_dma_map_page(rdma, ctxt, virt_to_page(base),
offset_in_page(base), len);
if (!iov->iov_len)
return 0;
return svc_rdma_page_dma_map(data, virt_to_page(iov->iov_base),
offset_in_page(iov->iov_base),
iov->iov_len);
}
/**
* svc_rdma_xb_dma_map - DMA map all segments of an xdr_buf
* @xdr: xdr_buf containing portion of an RPC message to transmit
* @data: pointer to arguments
*
* Returns:
* %0 if DMA mapping was successful
* %-EIO if DMA mapping failed
*
* On failure, any DMA mappings that have been already done must be
* unmapped by the caller.
*/
static int svc_rdma_xb_dma_map(const struct xdr_buf *xdr, void *data)
{
unsigned int len, remaining;
unsigned long pageoff;
struct page **ppages;
int ret;
ret = svc_rdma_iov_dma_map(data, &xdr->head[0]);
if (ret < 0)
return ret;
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
pageoff = offset_in_page(xdr->page_base);
remaining = xdr->page_len;
while (remaining) {
len = min_t(u32, PAGE_SIZE - pageoff, remaining);
ret = svc_rdma_page_dma_map(data, *ppages++, pageoff, len);
if (ret < 0)
return ret;
remaining -= len;
pageoff = 0;
}
ret = svc_rdma_iov_dma_map(data, &xdr->tail[0]);
if (ret < 0)
return ret;
return xdr->len;
}
struct svc_rdma_pullup_data {
@ -688,22 +760,22 @@ static int svc_rdma_pull_up_reply_msg(const struct svcxprt_rdma *rdma,
* @rctxt: Write and Reply chunks provided by client
* @xdr: prepared xdr_buf containing RPC message
*
* Load the xdr_buf into the ctxt's sge array, and DMA map each
* element as it is added. The Send WR's num_sge field is set.
* Returns:
* %0 if DMA mapping was successful.
* %-EMSGSIZE if a buffer manipulation problem occurred
* %-EIO if DMA mapping failed
*
* Returns zero on success, or a negative errno on failure.
* The Send WR's num_sge field is set in all cases.
*/
int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_recv_ctxt *rctxt,
struct xdr_buf *xdr)
const struct xdr_buf *xdr)
{
unsigned int len, remaining;
unsigned long page_off;
struct page **ppages;
unsigned char *base;
u32 xdr_pad;
int ret;
struct svc_rdma_map_data args = {
.md_rdma = rdma,
.md_ctxt = sctxt,
};
/* Set up the (persistently-mapped) transport header SGE. */
sctxt->sc_send_wr.num_sge = 1;
@ -712,7 +784,7 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
/* If there is a Reply chunk, nothing follows the transport
* header, and we're done here.
*/
if (rctxt && rctxt->rc_reply_chunk)
if (!pcl_is_empty(&rctxt->rc_reply_pcl))
return 0;
/* For pull-up, svc_rdma_send() will sync the transport header.
@ -721,58 +793,8 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
if (svc_rdma_pull_up_needed(rdma, sctxt, rctxt, xdr))
return svc_rdma_pull_up_reply_msg(rdma, sctxt, rctxt, xdr);
++sctxt->sc_cur_sge_no;
ret = svc_rdma_dma_map_buf(rdma, sctxt,
xdr->head[0].iov_base,
xdr->head[0].iov_len);
if (ret < 0)
return ret;
/* If a Write chunk is present, the xdr_buf's page list
* is not included inline. However the Upper Layer may
* have added XDR padding in the tail buffer, and that
* should not be included inline.
*/
if (rctxt && rctxt->rc_write_list) {
base = xdr->tail[0].iov_base;
len = xdr->tail[0].iov_len;
xdr_pad = xdr_pad_size(xdr->page_len);
if (len && xdr_pad) {
base += xdr_pad;
len -= xdr_pad;
}
goto tail;
}
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
page_off = xdr->page_base & ~PAGE_MASK;
remaining = xdr->page_len;
while (remaining) {
len = min_t(u32, PAGE_SIZE - page_off, remaining);
++sctxt->sc_cur_sge_no;
ret = svc_rdma_dma_map_page(rdma, sctxt, *ppages++,
page_off, len);
if (ret < 0)
return ret;
remaining -= len;
page_off = 0;
}
base = xdr->tail[0].iov_base;
len = xdr->tail[0].iov_len;
tail:
if (len) {
++sctxt->sc_cur_sge_no;
ret = svc_rdma_dma_map_buf(rdma, sctxt, base, len);
if (ret < 0)
return ret;
}
return 0;
return pcl_process_nonpayloads(&rctxt->rc_write_pcl, xdr,
svc_rdma_xb_dma_map, &args);
}
/* The svc_rqst and all resources it owns are released as soon as