When counting the number of SGEs needed to construct a Send request,
do not count result payloads. And, when copying the Reply message
into the pull-up buffer, result payloads are not to be copied to the
Send buffer.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc_rdma.h | 2
include/trace/events/rpcrdma.h | 20 ++-
net/sunrpc/xprtrdma/svc_rdma_backchannel.c | 14 +-
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 9 +
net/sunrpc/xprtrdma/svc_rdma_sendto.c | 188 +++++++++++++++++-----------
5 files changed, 146 insertions(+), 87 deletions(-)
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index d9148787efff..7090af1a9791 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -182,6 +182,8 @@ extern void svc_rdma_handle_bc_reply(struct svc_rqst *rqstp,
/* svc_rdma_recvfrom.c */
extern void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma);
extern bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma);
+extern struct svc_rdma_recv_ctxt *
+ svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma);
extern void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt);
extern void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma);
diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
index 5218e0f9596a..afc58accb9cf 100644
--- a/include/trace/events/rpcrdma.h
+++ b/include/trace/events/rpcrdma.h
@@ -1805,20 +1805,30 @@ TRACE_EVENT(svcrdma_small_wrch_err,
TRACE_EVENT(svcrdma_send_pullup,
TP_PROTO(
- unsigned int len
+ const struct svc_rdma_send_ctxt *ctxt,
+ unsigned int msglen
),
- TP_ARGS(len),
+ TP_ARGS(ctxt, msglen),
TP_STRUCT__entry(
- __field(unsigned int, len)
+ __field(u32, cq_id)
+ __field(int, completion_id)
+ __field(unsigned int, hdrlen)
+ __field(unsigned int, msglen)
),
TP_fast_assign(
- __entry->len = len;
+ __entry->cq_id = ctxt->sc_cid.ci_queue_id;
+ __entry->completion_id = ctxt->sc_cid.ci_completion_id;
+ __entry->hdrlen = ctxt->sc_hdrbuf.len,
+ __entry->msglen = msglen;
),
- TP_printk("len=%u", __entry->len)
+ TP_printk("cq_id=%u cid=%d hdr=%u msg=%u (total %u)",
+ __entry->cq_id, __entry->completion_id,
+ __entry->hdrlen, __entry->msglen,
+ __entry->hdrlen + __entry->msglen)
);
TRACE_EVENT(svcrdma_send_err,
diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index 5e7c4ba9e147..63f8be974df2 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -74,11 +74,17 @@ void svc_rdma_handle_bc_reply(struct svc_rqst *rqstp,
*/
static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
struct rpc_rqst *rqst,
- struct svc_rdma_send_ctxt *ctxt)
+ struct svc_rdma_send_ctxt *sctxt)
{
+ struct svc_rdma_recv_ctxt *rctxt;
int ret;
- ret = svc_rdma_map_reply_msg(rdma, ctxt, NULL, &rqst->rq_snd_buf);
+ rctxt = svc_rdma_recv_ctxt_get(rdma);
+ if (!rctxt)
+ return -EIO;
+
+ ret = svc_rdma_map_reply_msg(rdma, sctxt, rctxt, &rqst->rq_snd_buf);
+ svc_rdma_recv_ctxt_put(rdma, rctxt);
if (ret < 0)
return -EIO;
@@ -86,8 +92,8 @@ static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
* the rq_buffer before all retransmits are complete.
*/
get_page(virt_to_page(rqst->rq_buffer));
- ctxt->sc_send_wr.opcode = IB_WR_SEND;
- return svc_rdma_send(rdma, ctxt);
+ sctxt->sc_send_wr.opcode = IB_WR_SEND;
+ return svc_rdma_send(rdma, sctxt);
}
/* Server-side transport endpoint wants a whole page for its send
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 7d44e9d2e7a3..af32c3ad45a6 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -194,8 +194,13 @@ void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma)
}
}
-static struct svc_rdma_recv_ctxt *
-svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma)
+/**
+ * svc_rdma_recv_ctxt_get - Allocate a recv_ctxt
+ * @rdma: controlling svcxprt_rdma
+ *
+ * Returns a recv_ctxt or (rarely) NULL if none are available.
+ */
+struct svc_rdma_recv_ctxt *svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma)
{
struct svc_rdma_recv_ctxt *ctxt;
struct llist_node *node;
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index fd8d62b1e640..b21beaa0114e 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -531,6 +531,45 @@ static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
offset_in_page(base), len);
}
+struct svc_rdma_pullup_data {
+ u8 *pd_dest;
+ unsigned int pd_length;
+ unsigned int pd_num_sges;
+};
+
+/**
+ * svc_rdma_xb_count_sges - Count how many SGEs will be needed
+ * @xdr: xdr_buf containing portion of an RPC message to transmit
+ * @data: pointer to arguments
+ *
+ * Returns:
+ * Number of SGEs needed to Send the contents of @xdr inline
+ */
+static int svc_rdma_xb_count_sges(const struct xdr_buf *xdr,
+ void *data)
+{
+ struct svc_rdma_pullup_data *args = data;
+ unsigned int remaining;
+ unsigned long offset;
+
+ if (xdr->head[0].iov_len)
+ ++args->pd_num_sges;
+
+ offset = offset_in_page(xdr->page_base);
+ remaining = xdr->page_len;
+ while (remaining) {
+ ++args->pd_num_sges;
+ remaining -= min_t(u32, PAGE_SIZE - offset, remaining);
+ offset = 0;
+ }
+
+ if (xdr->tail[0].iov_len)
+ ++args->pd_num_sges;
+
+ args->pd_length += xdr->len;
+ return 0;
+}
+
/**
* svc_rdma_pull_up_needed - Determine whether to use pull-up
* @rdma: controlling transport
@@ -539,50 +578,71 @@ static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
* @xdr: xdr_buf containing RPC message to transmit
*
* Returns:
- * %true if pull-up must be used
- * %false otherwise
+ * %true if pull-up must be used
+ * %false otherwise
*/
-static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
- struct svc_rdma_send_ctxt *sctxt,
+static bool svc_rdma_pull_up_needed(const struct svcxprt_rdma *rdma,
+ const struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_recv_ctxt *rctxt,
- struct xdr_buf *xdr)
+ const struct xdr_buf *xdr)
{
- bool write_chunk_present = rctxt && rctxt->rc_write_list;
- int elements;
+ /* Resources needed for the transport header */
+ struct svc_rdma_pullup_data args = {
+ .pd_length = sctxt->sc_hdrbuf.len,
+ .pd_num_sges = 1,
+ };
+ int ret;
- /* For small messages, copying bytes is cheaper than DMA mapping.
- */
- if (!write_chunk_present &&
- sctxt->sc_hdrbuf.len + xdr->len < RPCRDMA_PULLUP_THRESH)
+ ret = pcl_process_nonpayloads(&rctxt->rc_write_pcl, xdr,
+ svc_rdma_xb_count_sges, &args);
+ if (ret < 0)
+ return false;
+
+ if (args.pd_length < RPCRDMA_PULLUP_THRESH)
return true;
+ return args.pd_num_sges >= rdma->sc_max_send_sges;
+}
- /* Check whether the xdr_buf has more elements than can
- * fit in a single RDMA Send.
- */
- /* xdr->head */
- elements = 1;
-
- /* xdr->pages */
- if (!rctxt || !rctxt->rc_write_list) {
- unsigned int remaining;
- unsigned long pageoff;
-
- pageoff = xdr->page_base & ~PAGE_MASK;
- remaining = xdr->page_len;
- while (remaining) {
- ++elements;
- remaining -= min_t(u32, PAGE_SIZE - pageoff,
- remaining);
- pageoff = 0;
- }
+/**
+ * svc_rdma_xb_linearize - Copy region of xdr_buf to flat buffer
+ * @xdr: xdr_buf containing portion of an RPC message to copy
+ * @data: pointer to arguments
+ *
+ * Returns:
+ * Always zero.
+ */
+static int svc_rdma_xb_linearize(const struct xdr_buf *xdr,
+ void *data)
+{
+ struct svc_rdma_pullup_data *args = data;
+ unsigned int len, remaining;
+ unsigned long pageoff;
+ struct page **ppages;
+
+ if (xdr->head[0].iov_len) {
+ memcpy(args->pd_dest, xdr->head[0].iov_base, xdr->head[0].iov_len);
+ args->pd_dest += xdr->head[0].iov_len;
}
- /* xdr->tail */
- if (xdr->tail[0].iov_len)
- ++elements;
+ 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);
+ memcpy(args->pd_dest, page_address(*ppages) + pageoff, len);
+ remaining -= len;
+ args->pd_dest += len;
+ pageoff = 0;
+ ppages++;
+ }
- /* assume 1 SGE is needed for the transport header */
- return elements >= rdma->sc_max_send_sges;
+ if (xdr->tail[0].iov_len) {
+ memcpy(args->pd_dest, xdr->tail[0].iov_base, xdr->tail[0].iov_len);
+ args->pd_dest += xdr->tail[0].iov_len;
+ }
+
+ args->pd_length += xdr->len;
+ return 0;
}
/**
@@ -595,54 +655,30 @@ static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
* The device is not capable of sending the reply directly.
* Assemble the elements of @xdr into the transport header buffer.
*
- * Returns zero on success, or a negative errno on failure.
+ * Assumptions:
+ * pull_up_needed has determined that @xdr will fit in the buffer.
+ *
+ * Returns:
+ * %0 if pull-up was successful
+ * %-EMSGSIZE if a buffer manipulation problem occurred
*/
-static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
+static int svc_rdma_pull_up_reply_msg(const struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_recv_ctxt *rctxt,
const struct xdr_buf *xdr)
{
- unsigned char *dst, *tailbase;
- unsigned int taillen;
-
- dst = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len;
- memcpy(dst, xdr->head[0].iov_base, xdr->head[0].iov_len);
- dst += xdr->head[0].iov_len;
-
- tailbase = xdr->tail[0].iov_base;
- taillen = xdr->tail[0].iov_len;
- if (rctxt && rctxt->rc_write_list) {
- u32 xdrpad;
-
- xdrpad = xdr_pad_size(xdr->page_len);
- if (taillen && xdrpad) {
- tailbase += xdrpad;
- taillen -= xdrpad;
- }
- } else {
- unsigned int len, remaining;
- unsigned long pageoff;
- struct page **ppages;
-
- ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
- pageoff = xdr->page_base & ~PAGE_MASK;
- remaining = xdr->page_len;
- while (remaining) {
- len = min_t(u32, PAGE_SIZE - pageoff, remaining);
-
- memcpy(dst, page_address(*ppages) + pageoff, len);
- remaining -= len;
- dst += len;
- pageoff = 0;
- ppages++;
- }
- }
+ struct svc_rdma_pullup_data args = {
+ .pd_dest = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len,
+ };
+ int ret;
- if (taillen)
- memcpy(dst, tailbase, taillen);
+ ret = pcl_process_nonpayloads(&rctxt->rc_write_pcl, xdr,
+ svc_rdma_xb_linearize, &args);
+ if (ret < 0)
+ return ret;
- sctxt->sc_sges[0].length += xdr->len;
- trace_svcrdma_send_pullup(sctxt->sc_sges[0].length);
+ sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len + args.pd_length;
+ trace_svcrdma_send_pullup(sctxt, args.pd_length);
return 0;
}
