Merge branches 'clk-ingenic', 'clk-mtk-mux', 'clk-qcom-sdm845-pcie', 'clk-mtk-crit...

[linux-2.6-microblaze.git] / net / sunrpc / xprtrdma / svc_rdma_sendto.c

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index cf51b8f..1f20011 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -537,6 +537,99 @@ 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.
+ */
+static bool svc_rdma_pull_up_needed(struct svcxprt_rdma *rdma,
+                                   struct xdr_buf *xdr,
+                                   __be32 *wr_lst)
+{
+       int elements;
+
+       /* xdr->head */
+       elements = 1;
+
+       /* xdr->pages */
+       if (!wr_lst) {
+               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;
+               }
+       }
+
+       /* xdr->tail */
+       if (xdr->tail[0].iov_len)
+               ++elements;
+
+       /* assume 1 SGE is needed for the transport header */
+       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.
+ */
+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)
+{
+       unsigned char *dst, *tailbase;
+       unsigned int taillen;
+
+       dst = ctxt->sc_xprt_buf;
+       dst += ctxt->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) {
+               u32 xdrpad;
+
+               xdrpad = xdr_padsize(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), len);
+                       remaining -= len;
+                       dst += len;
+                       pageoff = 0;
+               }
+       }
+
+       if (taillen)
+               memcpy(dst, tailbase, taillen);
+
+       ctxt->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,
+                                     DMA_TO_DEVICE);
+
+       return 0;
+}
+
 /* svc_rdma_map_reply_msg - Map the buffer holding RPC message
  * @rdma: controlling transport
  * @ctxt: send_ctxt for the Send WR
@@ -559,8 +652,10 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        u32 xdr_pad;
        int ret;
 
-       if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
-               return -EIO;
+       if (svc_rdma_pull_up_needed(rdma, xdr, wr_lst))
+               return svc_rdma_pull_up_reply_msg(rdma, ctxt, xdr, wr_lst);
+
+       ++ctxt->sc_cur_sge_no;
        ret = svc_rdma_dma_map_buf(rdma, ctxt,
                                   xdr->head[0].iov_base,
                                   xdr->head[0].iov_len);
@@ -591,8 +686,7 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        while (remaining) {
                len = min_t(u32, PAGE_SIZE - page_off, remaining);
 
-               if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
-                       return -EIO;
+               ++ctxt->sc_cur_sge_no;
                ret = svc_rdma_dma_map_page(rdma, ctxt, *ppages++,
                                            page_off, len);
                if (ret < 0)
@@ -606,8 +700,7 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
        len = xdr->tail[0].iov_len;
 tail:
        if (len) {
-               if (++ctxt->sc_cur_sge_no >= rdma->sc_max_send_sges)
-                       return -EIO;
+               ++ctxt->sc_cur_sge_no;
                ret = svc_rdma_dma_map_buf(rdma, ctxt, base, len);
                if (ret < 0)
                        return ret;