XPRTRDMA: correct an rpc/rdma inline send marshaling error

Certain client rpc's which contain both lengthy page-contained
metadata and a non-empty xdr_tail buffer require careful handling
to avoid overlapped memory copying. Rearranging of existing rpcrdma
marshaling code avoids it; this fixes an NFSv4 symlink creation error
detected with connectathon basic/test8 to multiple servers.

Signed-off-by: Tom Talpey <tmtalpey@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 14 insertions, 12 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 14106d26bb95..e5e28d1946a4 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -310,6 +310,19 @@ rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
                 __func__, pad, destp, rqst->rq_slen, curlen);
 
         copy_len = rqst->rq_snd_buf.page_len;
+
+        if (rqst->rq_snd_buf.tail[0].iov_len) {
+                curlen = rqst->rq_snd_buf.tail[0].iov_len;
+                if (destp + copy_len != rqst->rq_snd_buf.tail[0].iov_base) {
+                        memmove(destp + copy_len,
+                                rqst->rq_snd_buf.tail[0].iov_base, curlen);
+                        r_xprt->rx_stats.pullup_copy_count += curlen;
+                }
+                dprintk("RPC:       %s: tail destp 0x%p len %d\n",
+                        __func__, destp + copy_len, curlen);
+                rqst->rq_svec[0].iov_len += curlen;
+        }
+
         r_xprt->rx_stats.pullup_copy_count += copy_len;
         npages = PAGE_ALIGN(rqst->rq_snd_buf.page_base+copy_len) >> PAGE_SHIFT;
         for (i = 0; copy_len && i < npages; i++) {
@@ -332,17 +345,6 @@ rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
                 destp += curlen;
                 copy_len -= curlen;
         }
-        if (rqst->rq_snd_buf.tail[0].iov_len) {
-                curlen = rqst->rq_snd_buf.tail[0].iov_len;
-                if (destp != rqst->rq_snd_buf.tail[0].iov_base) {
-                        memcpy(destp,
-                                rqst->rq_snd_buf.tail[0].iov_base, curlen);
-                        r_xprt->rx_stats.pullup_copy_count += curlen;
-                }
-                dprintk("RPC:       %s: tail destp 0x%p len %d curlen %d\n",
-                        __func__, destp, copy_len, curlen);
-                rqst->rq_svec[0].iov_len += curlen;
-        }
         /* header now contains entire send message */
         return pad;
 }
@@ -656,7 +658,7 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
                 if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
                         curlen = rqst->rq_rcv_buf.tail[0].iov_len;
                 if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
-                        memcpy(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
+                        memmove(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
                 dprintk("RPC:       %s: tail srcp 0x%p len %d curlen %d\n",
                         __func__, srcp, copy_len, curlen);
                 rqst->rq_rcv_buf.tail[0].iov_len = curlen;