svcrdma: Introduce svc_rdma_recv_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
To reduce contention further, separate the use of these objects in
the Receive and Send paths in svcrdma.

Subsequent patches will take advantage of this separation by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and recv_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

As a final clean up, helpers related to recv_ctxt are moved closer
to the functions that use them.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 42 insertions, 42 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 887ceef125b2..c080ce20ff40 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright (c) 2016 Oracle.  All rights reserved.
+ * Copyright (c) 2016-2018 Oracle.  All rights reserved.
  *
  * Use the core R/W API to move RPC-over-RDMA Read and Write chunks.
  */
@@ -227,7 +227,7 @@ static void svc_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc)
 /* State for pulling a Read chunk.
  */
 struct svc_rdma_read_info {
-	struct svc_rdma_op_ctxt		*ri_readctxt;
+	struct svc_rdma_recv_ctxt	*ri_readctxt;
 	unsigned int			ri_position;
 	unsigned int			ri_pageno;
 	unsigned int			ri_pageoff;
@@ -282,10 +282,10 @@ static void svc_rdma_wc_read_done(struct ib_cq *cq, struct ib_wc *wc)
 			pr_err("svcrdma: read ctx: %s (%u/0x%x)\n",
 			       ib_wc_status_msg(wc->status),
 			       wc->status, wc->vendor_err);
-		svc_rdma_put_context(info->ri_readctxt, 1);
+		svc_rdma_recv_ctxt_put(rdma, info->ri_readctxt, 1);
 	} else {
 		spin_lock(&rdma->sc_rq_dto_lock);
-		list_add_tail(&info->ri_readctxt->list,
+		list_add_tail(&info->ri_readctxt->rc_list,
 			      &rdma->sc_read_complete_q);
 		spin_unlock(&rdma->sc_rq_dto_lock);
 
@@ -607,7 +607,7 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
 				       struct svc_rqst *rqstp,
 				       u32 rkey, u32 len, u64 offset)
 {
-	struct svc_rdma_op_ctxt *head = info->ri_readctxt;
+	struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
 	struct svc_rdma_chunk_ctxt *cc = &info->ri_cc;
 	struct svc_rdma_rw_ctxt *ctxt;
 	unsigned int sge_no, seg_len;
@@ -625,10 +625,10 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
 		seg_len = min_t(unsigned int, len,
 				PAGE_SIZE - info->ri_pageoff);
 
-		head->arg.pages[info->ri_pageno] =
+		head->rc_arg.pages[info->ri_pageno] =
 			rqstp->rq_pages[info->ri_pageno];
 		if (!info->ri_pageoff)
-			head->count++;
+			head->rc_page_count++;
 
 		sg_set_page(sg, rqstp->rq_pages[info->ri_pageno],
 			    seg_len, info->ri_pageoff);
@@ -705,9 +705,9 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp,
 }
 
 /* Construct RDMA Reads to pull over a normal Read chunk. The chunk
- * data lands in the page list of head->arg.pages.
+ * data lands in the page list of head->rc_arg.pages.
  *
- * Currently NFSD does not look at the head->arg.tail[0] iovec.
+ * Currently NFSD does not look at the head->rc_arg.tail[0] iovec.
  * Therefore, XDR round-up of the Read chunk and trailing
  * inline content must both be added at the end of the pagelist.
  */
@@ -715,10 +715,10 @@ static int svc_rdma_build_normal_read_chunk(struct svc_rqst *rqstp,
 					    struct svc_rdma_read_info *info,
 					    __be32 *p)
 {
-	struct svc_rdma_op_ctxt *head = info->ri_readctxt;
+	struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
 	int ret;
 
-	info->ri_pageno = head->hdr_count;
+	info->ri_pageno = head->rc_hdr_count;
 	info->ri_pageoff = 0;
 
 	ret = svc_rdma_build_read_chunk(rqstp, info, p);
@@ -732,11 +732,11 @@ static int svc_rdma_build_normal_read_chunk(struct svc_rqst *rqstp,
 	 * chunk is not included in either the pagelist or in
 	 * the tail.
 	 */
-	head->arg.tail[0].iov_base =
-		head->arg.head[0].iov_base + info->ri_position;
-	head->arg.tail[0].iov_len =
-		head->arg.head[0].iov_len - info->ri_position;
-	head->arg.head[0].iov_len = info->ri_position;
+	head->rc_arg.tail[0].iov_base =
+		head->rc_arg.head[0].iov_base + info->ri_position;
+	head->rc_arg.tail[0].iov_len =
+		head->rc_arg.head[0].iov_len - info->ri_position;
+	head->rc_arg.head[0].iov_len = info->ri_position;
 
 	/* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2).
 	 *
@@ -749,9 +749,9 @@ static int svc_rdma_build_normal_read_chunk(struct svc_rqst *rqstp,
 	 */
 	info->ri_chunklen = XDR_QUADLEN(info->ri_chunklen) << 2;
 
-	head->arg.page_len = info->ri_chunklen;
-	head->arg.len += info->ri_chunklen;
-	head->arg.buflen += info->ri_chunklen;
+	head->rc_arg.page_len = info->ri_chunklen;
+	head->rc_arg.len += info->ri_chunklen;
+	head->rc_arg.buflen += info->ri_chunklen;
 
 out:
 	return ret;
@@ -760,7 +760,7 @@ out:
 /* Construct RDMA Reads to pull over a Position Zero Read chunk.
  * The start of the data lands in the first page just after
  * the Transport header, and the rest lands in the page list of
- * head->arg.pages.
+ * head->rc_arg.pages.
  *
  * Assumptions:
  *	- A PZRC has an XDR-aligned length (no implicit round-up).
@@ -772,11 +772,11 @@ static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp,
 					struct svc_rdma_read_info *info,
 					__be32 *p)
 {
-	struct svc_rdma_op_ctxt *head = info->ri_readctxt;
+	struct svc_rdma_recv_ctxt *head = info->ri_readctxt;
 	int ret;
 
-	info->ri_pageno = head->hdr_count - 1;
-	info->ri_pageoff = offset_in_page(head->byte_len);
+	info->ri_pageno = head->rc_hdr_count - 1;
+	info->ri_pageoff = offset_in_page(head->rc_byte_len);
 
 	ret = svc_rdma_build_read_chunk(rqstp, info, p);
 	if (ret < 0)
@@ -784,22 +784,22 @@ static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp,
 
 	trace_svcrdma_encode_pzr(info->ri_chunklen);
 
-	head->arg.len += info->ri_chunklen;
-	head->arg.buflen += info->ri_chunklen;
+	head->rc_arg.len += info->ri_chunklen;
+	head->rc_arg.buflen += info->ri_chunklen;
 
-	if (head->arg.buflen <= head->sge[0].length) {
+	if (head->rc_arg.buflen <= head->rc_sges[0].length) {
 		/* Transport header and RPC message fit entirely
 		 * in page where head iovec resides.
 		 */
-		head->arg.head[0].iov_len = info->ri_chunklen;
+		head->rc_arg.head[0].iov_len = info->ri_chunklen;
 	} else {
 		/* Transport header and part of RPC message reside
 		 * in the head iovec's page.
 		 */
-		head->arg.head[0].iov_len =
-				head->sge[0].length - head->byte_len;
-		head->arg.page_len =
-				info->ri_chunklen - head->arg.head[0].iov_len;
+		head->rc_arg.head[0].iov_len =
+			head->rc_sges[0].length - head->rc_byte_len;
+		head->rc_arg.page_len =
+			info->ri_chunklen - head->rc_arg.head[0].iov_len;
 	}
 
 out:
@@ -824,24 +824,24 @@ out:
  * - All Read segments in @p have the same Position value.
  */
 int svc_rdma_recv_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
-			     struct svc_rdma_op_ctxt *head, __be32 *p)
+			     struct svc_rdma_recv_ctxt *head, __be32 *p)
 {
 	struct svc_rdma_read_info *info;
 	struct page **page;
 	int ret;
 
 	/* The request (with page list) is constructed in
-	 * head->arg. Pages involved with RDMA Read I/O are
+	 * head->rc_arg. Pages involved with RDMA Read I/O are
 	 * transferred there.
 	 */
-	head->hdr_count = head->count;
-	head->arg.head[0] = rqstp->rq_arg.head[0];
-	head->arg.tail[0] = rqstp->rq_arg.tail[0];
-	head->arg.pages = head->pages;
-	head->arg.page_base = 0;
-	head->arg.page_len = 0;
-	head->arg.len = rqstp->rq_arg.len;
-	head->arg.buflen = rqstp->rq_arg.buflen;
+	head->rc_hdr_count = head->rc_page_count;
+	head->rc_arg.head[0] = rqstp->rq_arg.head[0];
+	head->rc_arg.tail[0] = rqstp->rq_arg.tail[0];
+	head->rc_arg.pages = head->rc_pages;
+	head->rc_arg.page_base = 0;
+	head->rc_arg.page_len = 0;
+	head->rc_arg.len = rqstp->rq_arg.len;
+	head->rc_arg.buflen = rqstp->rq_arg.buflen;
 
 	info = svc_rdma_read_info_alloc(rdma);
 	if (!info)
@@ -867,7 +867,7 @@ int svc_rdma_recv_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp,
 
 out:
 	/* Read sink pages have been moved from rqstp->rq_pages to
-	 * head->arg.pages. Force svc_recv to refill those slots
+	 * head->rc_arg.pages. Force svc_recv to refill those slots
 	 * in rq_pages.
 	 */
 	for (page = rqstp->rq_pages; page < rqstp->rq_respages; page++)