Merge tag 'nfsd-5.0-1' of git://linux-nfs.org/~bfields/linux

Pull nfsd fixes from Bruce Fields:
 "Two small nfsd bugfixes for 5.0, for an RDMA bug and a file clone bug"

* tag 'nfsd-5.0-1' of git://linux-nfs.org/~bfields/linux:
  svcrdma: Remove max_sge check at connect time
  nfsd: Fix error return values for nfsd4_clone_file_range()

3 files changed, 106 insertions, 14 deletions

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 9824e32b2f23..7dc98e14655d 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -557,9 +557,11 @@ __be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
         loff_t cloned;
 
         cloned = vfs_clone_file_range(src, src_pos, dst, dst_pos, count, 0);
+        if (cloned < 0)
+                return nfserrno(cloned);
         if (count && cloned != count)
-                cloned = -EINVAL;
-        return nfserrno(cloned < 0 ? cloned : 0);
+                return nfserrno(-EINVAL);
+        return 0;
 }
 
 ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index cf51b8f9b15f..1f200119268c 100644
--- 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;
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 924c17d46903..57f86c63a463 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -419,12 +419,9 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
         /* Transport header, head iovec, tail iovec */
         newxprt->sc_max_send_sges = 3;
         /* Add one SGE per page list entry */
-        newxprt->sc_max_send_sges += svcrdma_max_req_size / PAGE_SIZE;
-        if (newxprt->sc_max_send_sges > dev->attrs.max_send_sge) {
-                pr_err("svcrdma: too few Send SGEs available (%d needed)\n",
-                       newxprt->sc_max_send_sges);
-                goto errout;
-        }
+        newxprt->sc_max_send_sges += (svcrdma_max_req_size / PAGE_SIZE) + 1;
+        if (newxprt->sc_max_send_sges > dev->attrs.max_send_sge)
+                newxprt->sc_max_send_sges = dev->attrs.max_send_sge;
         newxprt->sc_max_req_size = svcrdma_max_req_size;
         newxprt->sc_max_requests = svcrdma_max_requests;
         newxprt->sc_max_bc_requests = svcrdma_max_bc_requests;