svcrdma: Update synopsis of svc_rdma_map_reply_msg()

Preparing for subsequent patches, no behavior change expected.

Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into those lower-level functions.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 42b6812..c506732 100644 (file)
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -193,8 +193,9 @@ extern void svc_rdma_sync_reply_hdr(struct svcxprt_rdma *rdma,
                                    struct svc_rdma_send_ctxt *ctxt,
                                    unsigned int len);
 extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
-                                 struct svc_rdma_send_ctxt *ctxt,
-                                 struct xdr_buf *xdr, __be32 *wr_lst);
+                                 struct svc_rdma_send_ctxt *sctxt,
+                                 const struct svc_rdma_recv_ctxt *rctxt,
+                                 struct xdr_buf *xdr);
 extern int svc_rdma_sendto(struct svc_rqst *);
 extern int svc_rdma_read_payload(struct svc_rqst *rqstp, unsigned int offset,
                                 unsigned int length);

diff --git a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
index 908e78b..ce1a7a7 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_backchannel.c
@@ -117,7 +117,7 @@ static int svc_rdma_bc_sendto(struct svcxprt_rdma *rdma,
 {
        int ret;
 
-       ret = svc_rdma_map_reply_msg(rdma, ctxt, &rqst->rq_snd_buf, NULL);
+       ret = svc_rdma_map_reply_msg(rdma, ctxt, NULL, &rqst->rq_snd_buf);
        if (ret < 0)
                return -EIO;
 

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 0b6ff55..0301b87 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -502,13 +502,19 @@ void svc_rdma_sync_reply_hdr(struct svcxprt_rdma *rdma,
                                      DMA_TO_DEVICE);
 }
 
-/* If the xdr_buf has more elements than the device can
- * transmit in a single RDMA Send, then the reply will
- * have to be copied into a bounce buffer.
+/**
+ * svc_rdma_pull_up_needed - Determine whether to use pull-up
+ * @rdma: controlling transport
+ * @rctxt: Write and Reply chunks provided by client
+ * @xdr: xdr_buf containing RPC message to transmit
+ *
+ * Returns:
+ *     %true if pull-up must be used
+ *     %false otherwise
  */
 static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
-                                   struct xdr_buf *xdr,
-                                   __be32 *wr_lst)
+                                   const struct svc_rdma_recv_ctxt *rctxt,
+                                   struct xdr_buf *xdr)
 {
        int elements;
 
@@ -516,7 +522,7 @@ static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
        elements = 1;
 
        /* xdr->pages */
-       if (!wr_lst) {
+       if (!rctxt || !rctxt->rc_write_list) {
                unsigned int remaining;
                unsigned long pageoff;
 
@@ -538,26 +544,35 @@ static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
        return elements >= rdma->sc_max_send_sges;
 }
 
-/* The device is not capable of sending the reply directly.
- * Assemble the elements of @xdr into the transport header
- * buffer.
+/**
+ * svc_rdma_pull_up_reply_msg - Copy Reply into a single buffer
+ * @rdma: controlling transport
+ * @sctxt: send_ctxt for the Send WR; xprt hdr is already prepared
+ * @rctxt: Write and Reply chunks provided by client
+ * @xdr: prepared xdr_buf containing RPC message
+ *
+ * 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.
  */
 static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
-                                     struct svc_rdma_send_ctxt *ctxt,
-                                     struct xdr_buf *xdr, __be32 *wr_lst)
+                                     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 = ctxt->sc_xprt_buf;
-       dst += ctxt->sc_sges[0].length;
+       dst = sctxt->sc_xprt_buf;
+       dst += sctxt->sc_sges[0].length;
 
        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 (wr_lst) {
+       if (rctxt && rctxt->rc_write_list) {
                u32 xdrpad;
 
                xdrpad = xdr_pad_size(xdr->page_len);
@@ -586,20 +601,20 @@ static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
        if (taillen)
                memcpy(dst, tailbase, taillen);
 
-       ctxt->sc_sges[0].length += xdr->len;
+       sctxt->sc_sges[0].length += xdr->len;
        ib_dma_sync_single_for_device(rdma->sc_pd->device,
-                                     ctxt->sc_sges[0].addr,
-                                     ctxt->sc_sges[0].length,
+                                     sctxt->sc_sges[0].addr,
+                                     sctxt->sc_sges[0].length,
                                      DMA_TO_DEVICE);
 
        return 0;
 }
 
-/* svc_rdma_map_reply_msg - Map the buffer holding RPC message
+/* svc_rdma_map_reply_msg - DMA map the buffer holding RPC message
  * @rdma: controlling transport
- * @ctxt: send_ctxt for the Send WR
+ * @sctxt: send_ctxt for the Send WR
+ * @rctxt: Write and Reply chunks provided by client
  * @xdr: prepared xdr_buf containing RPC message
- * @wr_lst: pointer to Call header's Write list, or NULL
  *
  * Load the xdr_buf into the ctxt's sge array, and DMA map each
  * element as it is added.
@@ -607,8 +622,9 @@ static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
  * Returns zero on success, or a negative errno on failure.
  */
 int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
-                          struct svc_rdma_send_ctxt *ctxt,
-                          struct xdr_buf *xdr, __be32 *wr_lst)
+                          struct svc_rdma_send_ctxt *sctxt,
+                          const struct svc_rdma_recv_ctxt *rctxt,
+                          struct xdr_buf *xdr)
 {
        unsigned int len, remaining;
        unsigned long page_off;
@@ -617,11 +633,11 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        u32 xdr_pad;
        int ret;
 
-       if (svc_rdma_pull_up_needed(rdma, xdr, wr_lst))
-               return svc_rdma_pull_up_reply_msg(rdma, ctxt, xdr, wr_lst);
+       if (svc_rdma_pull_up_needed(rdma, rctxt, xdr))
+               return svc_rdma_pull_up_reply_msg(rdma, sctxt, rctxt, xdr);
 
-       ++ctxt->sc_cur_sge_no;
-       ret = svc_rdma_dma_map_buf(rdma, ctxt,
+       ++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)
@@ -632,7 +648,7 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
         * have added XDR padding in the tail buffer, and that
         * should not be included inline.
         */
-       if (wr_lst) {
+       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);
@@ -651,8 +667,8 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        while (remaining) {
                len = min_t(u32, PAGE_SIZE - page_off, remaining);
 
-               ++ctxt->sc_cur_sge_no;
-               ret = svc_rdma_dma_map_page(rdma, ctxt, *ppages++,
+               ++sctxt->sc_cur_sge_no;
+               ret = svc_rdma_dma_map_page(rdma, sctxt, *ppages++,
                                            page_off, len);
                if (ret < 0)
                        return ret;
@@ -665,8 +681,8 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        len = xdr->tail[0].iov_len;
 tail:
        if (len) {
-               ++ctxt->sc_cur_sge_no;
-               ret = svc_rdma_dma_map_buf(rdma, ctxt, base, len);
+               ++sctxt->sc_cur_sge_no;
+               ret = svc_rdma_dma_map_buf(rdma, sctxt, base, len);
                if (ret < 0)
                        return ret;
        }
@@ -720,8 +736,8 @@ static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
        int ret;
 
        if (!rp_ch) {
-               ret = svc_rdma_map_reply_msg(rdma, sctxt,
-                                            &rqstp->rq_res, wr_lst);
+               ret = svc_rdma_map_reply_msg(rdma, sctxt, rctxt,
+                                            &rqstp->rq_res);
                if (ret < 0)
                        return ret;
        }