svcrdma: Fix byte-swapping in svc_rdma_sendto.c

In send_write_chunks(), we have:

	for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
	     xfer_len && chunk_no < arg_ary->wc_nchunks;
	     chunk_no++) {
		 . . .
	}

Note that arg_ary->wc_nchunk is in network byte-order. For the
comparison to work correctly, both have to be in native byte-order.

In send_reply_chunks, we have:

	write_len = min(xfer_len, htonl(ch->rs_length));

xfer_len is in native byte-order, and ch->rs_length is in
network byte-order. be32_to_cpu() is the correct byte swap
for ch->rs_length.

As an additional clean up, replace ntohl() with be32_to_cpu() in
a few other places.

This appears to address a problem with large rsize hangs while
using PHYSICAL memory registration. I suspect that is the only
registration mode that uses more than one chunk element.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=248
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 7de33d1af9b6d6c25367e3633dc98fb148b49945..109e9670be8c9e50f84889cf1baa99eb7ed1dafc 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -240,6 +240,7 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
        u32 xdr_off;
        int chunk_off;
        int chunk_no;
+       int nchunks;
        struct rpcrdma_write_array *arg_ary;
        struct rpcrdma_write_array *res_ary;
        int ret;
@@ -251,14 +252,15 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
                &rdma_resp->rm_body.rm_chunks[1];
 
        /* Write chunks start at the pagelist */
+       nchunks = be32_to_cpu(arg_ary->wc_nchunks);
        for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
-            xfer_len && chunk_no < arg_ary->wc_nchunks;
+            xfer_len && chunk_no < nchunks;
             chunk_no++) {
                struct rpcrdma_segment *arg_ch;
                u64 rs_offset;
 
                arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
-               write_len = min(xfer_len, ntohl(arg_ch->rs_length));
+               write_len = min(xfer_len, be32_to_cpu(arg_ch->rs_length));
 
                /* Prepare the response chunk given the length actually
                 * written */
@@ -270,7 +272,7 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
                chunk_off = 0;
                while (write_len) {
                        ret = send_write(xprt, rqstp,
-                                        ntohl(arg_ch->rs_handle),
+                                        be32_to_cpu(arg_ch->rs_handle),
                                         rs_offset + chunk_off,
                                         xdr_off,
                                         write_len,
@@ -318,13 +320,13 @@ static int send_reply_chunks(struct svcxprt_rdma *xprt,
                &rdma_resp->rm_body.rm_chunks[2];
 
        /* xdr offset starts at RPC message */
-       nchunks = ntohl(arg_ary->wc_nchunks);
+       nchunks = be32_to_cpu(arg_ary->wc_nchunks);
        for (xdr_off = 0, chunk_no = 0;
             xfer_len && chunk_no < nchunks;
             chunk_no++) {
                u64 rs_offset;
                ch = &arg_ary->wc_array[chunk_no].wc_target;
-               write_len = min(xfer_len, htonl(ch->rs_length));
+               write_len = min(xfer_len, be32_to_cpu(ch->rs_length));
 
                /* Prepare the reply chunk given the length actually
                 * written */
@@ -335,7 +337,7 @@ static int send_reply_chunks(struct svcxprt_rdma *xprt,
                chunk_off = 0;
                while (write_len) {
                        ret = send_write(xprt, rqstp,
-                                        ntohl(ch->rs_handle),
+                                        be32_to_cpu(ch->rs_handle),
                                         rs_offset + chunk_off,
                                         xdr_off,
                                         write_len,