diff mbox series

[v2,2/5] SUNRPC: Revert 579900670ac7 ("svcrdma: Remove unused sc_pages field")

Message ID 168657900778.5619.16189837402481584636.stgit@manet.1015granger.net (mailing list archive)
State Not Applicable
Headers show
Series svcrdma: Go back to releasing pages-under-I/O | expand

Commit Message

Chuck Lever June 12, 2023, 2:10 p.m. UTC 
From: Chuck Lever <chuck.lever@oracle.com>

Pre-requisite for releasing pages in the send completion handler.
Reverted by hand: patch -R would not apply cleanly.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h       |    3 ++-
 net/sunrpc/xprtrdma/svc_rdma_sendto.c |   25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index a0f3ea357977..8e654da55170 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -158,8 +158,9 @@  struct svc_rdma_send_ctxt {
 	struct xdr_buf		sc_hdrbuf;
 	struct xdr_stream	sc_stream;
 	void			*sc_xprt_buf;
+	int			sc_page_count;
 	int			sc_cur_sge_no;
-
+	struct page		*sc_pages[RPCSVC_MAXPAGES];
 	struct ib_sge		sc_sges[];
 };
 
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 8e7ccef74207..4c62bc41ea40 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -213,6 +213,7 @@  struct svc_rdma_send_ctxt *svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma)
 
 	ctxt->sc_send_wr.num_sge = 0;
 	ctxt->sc_cur_sge_no = 0;
+	ctxt->sc_page_count = 0;
 	return ctxt;
 
 out_empty:
@@ -227,6 +228,8 @@  struct svc_rdma_send_ctxt *svc_rdma_send_ctxt_get(struct svcxprt_rdma *rdma)
  * svc_rdma_send_ctxt_put - Return send_ctxt to free list
  * @rdma: controlling svcxprt_rdma
  * @ctxt: object to return to the free list
+ *
+ * Pages left in sc_pages are DMA unmapped and released.
  */
 void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
 			    struct svc_rdma_send_ctxt *ctxt)
@@ -234,6 +237,9 @@  void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
 	struct ib_device *device = rdma->sc_cm_id->device;
 	unsigned int i;
 
+	for (i = 0; i < ctxt->sc_page_count; ++i)
+		put_page(ctxt->sc_pages[i]);
+
 	/* The first SGE contains the transport header, which
 	 * remains mapped until @ctxt is destroyed.
 	 */
@@ -798,6 +804,25 @@  int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
 				       svc_rdma_xb_dma_map, &args);
 }
 
+/* The svc_rqst and all resources it owns are released as soon as
+ * svc_rdma_sendto returns. Transfer pages under I/O to the ctxt
+ * so they are released by the Send completion handler.
+ */
+static inline void svc_rdma_save_io_pages(struct svc_rqst *rqstp,
+					  struct svc_rdma_send_ctxt *ctxt)
+{
+	int i, pages = rqstp->rq_next_page - rqstp->rq_respages;
+
+	ctxt->sc_page_count += pages;
+	for (i = 0; i < pages; i++) {
+		ctxt->sc_pages[i] = rqstp->rq_respages[i];
+		rqstp->rq_respages[i] = NULL;
+	}
+
+	/* Prevent svc_xprt_release from releasing pages in rq_pages */
+	rqstp->rq_next_page = rqstp->rq_respages;
+}
+
 /* Prepare the portion of the RPC Reply that will be transmitted
  * via RDMA Send. The RPC-over-RDMA transport header is prepared
  * in sc_sges[0], and the RPC xdr_buf is prepared in following sges.