[PATCH v2 0/9] NFS/RDMA server patches proposed for v4.7

[PATCH v2 0/9] NFS/RDMA server patches proposed for v4.7

[Chuck Lever]

Shirley's server-side IPv6 patch, and a number of minor fixes and
clean-ups found during code review.

Available in the "nfsd-rdma-for-4.7" topic branch of this git repo:

git://git.linux-nfs.org/projects/cel/cel-2.6.git

Or for browsing:

http://git.linux-nfs.org/?p=cel/cel-2.6.git;a=log;h=refs/heads/nfsd-rdma-for-4.7


Changes since v1:
- Rebased on v4.6-rc6
- Patch converting CQs to workqueue has been dropped for now
- A number of clean-ups

---

Chuck Lever (8):
      svcrdma: Do not add XDR padding to xdr_buf page vector
      svcrdma: svc_rdma_put_context() is invoked twice in Send error path
      svcrdma: Remove superfluous line from rdma_read_chunks()
      svcrdma: Post Receives only for forward channel requests
      svcrdma: Drain QP before freeing svcrdma_xprt
      svcrdma: Eliminate code duplication in svc_rdma_recvfrom()
      svcrdma: Generalize svc_rdma_xdr_decode_req()
      svcrdma: Simplify the check for backward direction replies

Shirley Ma (1):
      svcrdma: Support IPv6 with NFS/RDMA


 fs/nfsd/nfs3xdr.c                        |    2 -
 include/linux/sunrpc/svc_rdma.h          |    2 -
 net/sunrpc/xprtrdma/svc_rdma_marshal.c   |   32 ++++++++++-----
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c  |   65 ++++++++----------------------
 net/sunrpc/xprtrdma/svc_rdma_sendto.c    |   28 ++++++-------
 net/sunrpc/xprtrdma/svc_rdma_transport.c |   17 +++++++-
 6 files changed, 70 insertions(+), 76 deletions(-)

--
Chuck Lever

[PATCH v2 1/9] svcrdma: Support IPv6 with NFS/RDMA

[Chuck Lever]

From: Shirley Ma <shirley.ma@oracle.com>

Allow both IPv4 and IPv6 to bind same port at the same time,
restricts use of the IPv6 socket to IPv6 communication.

Changes from v1:
 - Check rdma_set_afonly return value (suggested by Leon Romanovsky)

Changes from v2:
 - Acked-by: Leon Romanovsky <leonro@mellanox.com>

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_transport.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 9066896..d2680b8 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -789,7 +789,7 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
 	int ret;
 
 	dprintk("svcrdma: Creating RDMA socket\n");
-	if (sa->sa_family != AF_INET) {
+	if ((sa->sa_family != AF_INET) && (sa->sa_family != AF_INET6)) {
 		dprintk("svcrdma: Address family %d is not supported.\n", sa->sa_family);
 		return ERR_PTR(-EAFNOSUPPORT);
 	}
@@ -805,6 +805,16 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
 		goto err0;
 	}
 
+	/* Allow both IPv4 and IPv6 sockets to bind a single port
+	 * at the same time.
+	 */
+#if IS_ENABLED(CONFIG_IPV6)
+	ret = rdma_set_afonly(listen_id, 1);
+	if (ret) {
+		dprintk("svcrdma: rdma_set_afonly failed = %d\n", ret);
+		goto err1;
+	}
+#endif
 	ret = rdma_bind_addr(listen_id, sa);
 	if (ret) {
 		dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);

[PATCH v2 2/9] svcrdma: Do not add XDR padding to xdr_buf page vector

[Chuck Lever]

An xdr_buf has a head, a vector of pages, and a tail. Each
RPC request is presented to the NFS server contained in an
xdr_buf.

The RDMA transport would like to supply the NFS server with only
the NFS WRITE payload bytes in the page vector. In some common
cases, that would allow the NFS server to swap those pages right
into the target file's page cache.

Have the transport's RDMA Read logic put XDR pad bytes in the tail
iovec, and not in the pages that hold the data payload.

The NFSv3 WRITE XDR decoder is finicky about the lengths involved,
so make sure it is looking in the correct places when computing
the total length of the incoming NFS WRITE request.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs3xdr.c                       |    2 +-
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 2246454..c5eff5f 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -379,7 +379,7 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p,
 	 */
 	hdr = (void*)p - rqstp->rq_arg.head[0].iov_base;
 	dlen = rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len
-		- hdr;
+		+ rqstp->rq_arg.tail[0].iov_len - hdr;
 	/*
 	 * Round the length of the data which was specified up to
 	 * the next multiple of XDR units and then compare that
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 3b24a64..234be9d 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -488,7 +488,7 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
 	if (page_offset & 3) {
 		u32 pad = 4 - (page_offset & 3);
 
-		head->arg.page_len += pad;
+		head->arg.tail[0].iov_len += pad;
 		head->arg.len += pad;
 		head->arg.buflen += pad;
 		page_offset += pad;

[PATCH v2 3/9] svcrdma: svc_rdma_put_context() is invoked twice in Send error path

[Chuck Lever]

Get a fresh op_ctxt in send_reply() instead of in svc_rdma_sendto().
This ensures that svc_rdma_put_context() is invoked only once if
send_reply() fails.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_sendto.c |   28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 4f1b1c4..54d53330 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -463,25 +463,21 @@ static int send_reply(struct svcxprt_rdma *rdma,
 		      struct svc_rqst *rqstp,
 		      struct page *page,
 		      struct rpcrdma_msg *rdma_resp,
-		      struct svc_rdma_op_ctxt *ctxt,
 		      struct svc_rdma_req_map *vec,
 		      int byte_count)
 {
+	struct svc_rdma_op_ctxt *ctxt;
 	struct ib_send_wr send_wr;
 	u32 xdr_off;
 	int sge_no;
 	int sge_bytes;
 	int page_no;
 	int pages;
-	int ret;
-
-	ret = svc_rdma_repost_recv(rdma, GFP_KERNEL);
-	if (ret) {
-		svc_rdma_put_context(ctxt, 0);
-		return -ENOTCONN;
-	}
+	int ret = -EIO;
 
 	/* Prepare the context */
+	ctxt = svc_rdma_get_context(rdma);
+	ctxt->direction = DMA_TO_DEVICE;
 	ctxt->pages[0] = page;
 	ctxt->count = 1;
 
@@ -565,8 +561,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
  err:
 	svc_rdma_unmap_dma(ctxt);
 	svc_rdma_put_context(ctxt, 1);
-	pr_err("svcrdma: failed to send reply, rc=%d\n", ret);
-	return -EIO;
+	return ret;
 }
 
 void svc_rdma_prep_reply_hdr(struct svc_rqst *rqstp)
@@ -585,7 +580,6 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
 	int ret;
 	int inline_bytes;
 	struct page *res_page;
-	struct svc_rdma_op_ctxt *ctxt;
 	struct svc_rdma_req_map *vec;
 
 	dprintk("svcrdma: sending response for rqstp=%p\n", rqstp);
@@ -598,8 +592,6 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
 	rp_ary = svc_rdma_get_reply_array(rdma_argp, wr_ary);
 
 	/* Build an req vec for the XDR */
-	ctxt = svc_rdma_get_context(rdma);
-	ctxt->direction = DMA_TO_DEVICE;
 	vec = svc_rdma_get_req_map(rdma);
 	ret = svc_rdma_map_xdr(rdma, &rqstp->rq_res, vec, wr_ary != NULL);
 	if (ret)
@@ -635,7 +627,12 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
 		inline_bytes -= ret;
 	}
 
-	ret = send_reply(rdma, rqstp, res_page, rdma_resp, ctxt, vec,
+	/* Post a fresh Receive buffer _before_ sending the reply */
+	ret = svc_rdma_post_recv(rdma, GFP_KERNEL);
+	if (ret)
+		goto err1;
+
+	ret = send_reply(rdma, rqstp, res_page, rdma_resp, vec,
 			 inline_bytes);
 	if (ret < 0)
 		goto err1;
@@ -648,7 +645,8 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
 	put_page(res_page);
  err0:
 	svc_rdma_put_req_map(rdma, vec);
-	svc_rdma_put_context(ctxt, 0);
+	pr_err("svcrdma: Could not send reply, err=%d. Closing transport.\n",
+	       ret);
 	set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
 	return -ENOTCONN;
 }

[PATCH v2 4/9] svcrdma: Remove superfluous line from rdma_read_chunks()

[Chuck Lever]

Clean up: svc_rdma_get_read_chunk() already returns a pointer
to the Read list. No need to set "ch" again to the value it
already contains.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 234be9d..12e7899 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -447,10 +447,8 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
 	head->arg.len = rqstp->rq_arg.len;
 	head->arg.buflen = rqstp->rq_arg.buflen;
 
-	ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
-	position = be32_to_cpu(ch->rc_position);
-
 	/* RDMA_NOMSG: RDMA READ data should land just after RDMA RECV data */
+	position = be32_to_cpu(ch->rc_position);
 	if (position == 0) {
 		head->arg.pages = &head->pages[0];
 		page_offset = head->byte_len;

[PATCH v2 5/9] svcrdma: Post Receives only for forward channel requests

[Chuck Lever]

Since backward direction support was added, the rq_depth was
increased to accommodate both forward and backward Receives.

But only forward Receives need to be posted after a connection
has been accepted. Receives for backward replies are posted as
needed by svc_rdma_bc_sendto().

This doesn't break anything, but it means some resources are
wasted.

Fixes: 03fe9931536f ('svcrdma: Define maximum number of ...')
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_transport.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index d2680b8..02a112c 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -1083,7 +1083,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
 		newxprt->sc_dev_caps |= SVCRDMA_DEVCAP_READ_W_INV;
 
 	/* Post receive buffers */
-	for (i = 0; i < newxprt->sc_rq_depth; i++) {
+	for (i = 0; i < newxprt->sc_max_requests; i++) {
 		ret = svc_rdma_post_recv(newxprt, GFP_KERNEL);
 		if (ret) {
 			dprintk("svcrdma: failure posting receive buffers\n");

[PATCH v2 6/9] svcrdma: Drain QP before freeing svcrdma_xprt

[Chuck Lever]

If the server has forced a disconnect, the associated QP has not
been moved to the Error state, and thus Receives are still posted.

Ensure Receives (and any other outstanding WRs) are drained to
release resources that can be freed during teardown of the
svcrdma_xprt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_transport.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 02a112c..dd94401 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -1180,6 +1180,9 @@ static void __svc_rdma_free(struct work_struct *work)
 
 	dprintk("svcrdma: %s(%p)\n", __func__, rdma);
 
+	if (rdma->sc_qp && !IS_ERR(rdma->sc_qp))
+		ib_drain_qp(rdma->sc_qp);
+
 	/* We should only be called from kref_put */
 	if (atomic_read(&xprt->xpt_ref.refcount) != 0)
 		pr_err("svcrdma: sc_xprt still in use? (%d)\n",

[PATCH v2 7/9] svcrdma: Eliminate code duplication in svc_rdma_recvfrom()

[Chuck Lever]

Clean up.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |   26 +++++---------------------
 1 file changed, 5 insertions(+), 21 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 12e7899..1b72f35 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -508,11 +508,10 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
 	return ret;
 }
 
-static int rdma_read_complete(struct svc_rqst *rqstp,
-			      struct svc_rdma_op_ctxt *head)
+static void rdma_read_complete(struct svc_rqst *rqstp,
+			       struct svc_rdma_op_ctxt *head)
 {
 	int page_no;
-	int ret;
 
 	/* Copy RPC pages */
 	for (page_no = 0; page_no < head->count; page_no++) {
@@ -548,23 +547,6 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
 	rqstp->rq_arg.tail[0] = head->arg.tail[0];
 	rqstp->rq_arg.len = head->arg.len;
 	rqstp->rq_arg.buflen = head->arg.buflen;
-
-	/* Free the context */
-	svc_rdma_put_context(head, 0);
-
-	/* XXX: What should this be? */
-	rqstp->rq_prot = IPPROTO_MAX;
-	svc_xprt_copy_addrs(rqstp, rqstp->rq_xprt);
-
-	ret = rqstp->rq_arg.head[0].iov_len
-		+ rqstp->rq_arg.page_len
-		+ rqstp->rq_arg.tail[0].iov_len;
-	dprintk("svcrdma: deferred read ret=%d, rq_arg.len=%u, "
-		"rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len=%zu\n",
-		ret, rqstp->rq_arg.len,	rqstp->rq_arg.head[0].iov_base,
-		rqstp->rq_arg.head[0].iov_len);
-
-	return ret;
 }
 
 /* By convention, backchannel calls arrive via rdma_msg type
@@ -622,7 +604,8 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 				  dto_q);
 		list_del_init(&ctxt->dto_q);
 		spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock);
-		return rdma_read_complete(rqstp, ctxt);
+		rdma_read_complete(rqstp, ctxt);
+		goto complete;
 	} else if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
 		ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
 				  struct svc_rdma_op_ctxt,
@@ -680,6 +663,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 		return 0;
 	}
 
+complete:
 	ret = rqstp->rq_arg.head[0].iov_len
 		+ rqstp->rq_arg.page_len
 		+ rqstp->rq_arg.tail[0].iov_len;

[PATCH v2 8/9] svcrdma: Generalize svc_rdma_xdr_decode_req()

[Chuck Lever]

Clean up: Pass in just the piece of the svc_rqst that is needed
here.

While we're in the area, add an informative documenting comment.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h         |    2 +-
 net/sunrpc/xprtrdma/svc_rdma_marshal.c  |   32 +++++++++++++++++++++----------
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |    2 +-
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 3081339..d6917b8 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -199,7 +199,7 @@ extern int svc_rdma_handle_bc_reply(struct rpc_xprt *xprt,
 				    struct xdr_buf *rcvbuf);
 
 /* svc_rdma_marshal.c */
-extern int svc_rdma_xdr_decode_req(struct rpcrdma_msg *, struct svc_rqst *);
+extern int svc_rdma_xdr_decode_req(struct xdr_buf *);
 extern int svc_rdma_xdr_encode_error(struct svcxprt_rdma *,
 				     struct rpcrdma_msg *,
 				     enum rpcrdma_errcode, __be32 *);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_marshal.c b/net/sunrpc/xprtrdma/svc_rdma_marshal.c
index 765bca4..0ba9887 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_marshal.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_marshal.c
@@ -145,19 +145,32 @@ static __be32 *decode_reply_array(__be32 *va, __be32 *vaend)
 	return (__be32 *)&ary->wc_array[nchunks];
 }
 
-int svc_rdma_xdr_decode_req(struct rpcrdma_msg *rmsgp, struct svc_rqst *rqstp)
+/**
+ * svc_rdma_xdr_decode_req - Parse incoming RPC-over-RDMA header
+ * @rq_arg: Receive buffer
+ *
+ * On entry, xdr->head[0].iov_base points to first byte in the
+ * RPC-over-RDMA header.
+ *
+ * On successful exit, head[0] points to first byte past the
+ * RPC-over-RDMA header. For RDMA_MSG, this is the RPC message.
+ * The length of the RPC-over-RDMA header is returned.
+ */
+int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg)
 {
+	struct rpcrdma_msg *rmsgp;
 	__be32 *va, *vaend;
 	unsigned int len;
 	u32 hdr_len;
 
 	/* Verify that there's enough bytes for header + something */
-	if (rqstp->rq_arg.len <= RPCRDMA_HDRLEN_ERR) {
+	if (rq_arg->len <= RPCRDMA_HDRLEN_ERR) {
 		dprintk("svcrdma: header too short = %d\n",
-			rqstp->rq_arg.len);
+			rq_arg->len);
 		return -EINVAL;
 	}
 
+	rmsgp = (struct rpcrdma_msg *)rq_arg->head[0].iov_base;
 	if (rmsgp->rm_vers != rpcrdma_version) {
 		dprintk("%s: bad version %u\n", __func__,
 			be32_to_cpu(rmsgp->rm_vers));
@@ -189,10 +202,10 @@ int svc_rdma_xdr_decode_req(struct rpcrdma_msg *rmsgp, struct svc_rqst *rqstp)
 			be32_to_cpu(rmsgp->rm_body.rm_padded.rm_thresh);
 
 		va = &rmsgp->rm_body.rm_padded.rm_pempty[4];
-		rqstp->rq_arg.head[0].iov_base = va;
+		rq_arg->head[0].iov_base = va;
 		len = (u32)((unsigned long)va - (unsigned long)rmsgp);
-		rqstp->rq_arg.head[0].iov_len -= len;
-		if (len > rqstp->rq_arg.len)
+		rq_arg->head[0].iov_len -= len;
+		if (len > rq_arg->len)
 			return -EINVAL;
 		return len;
 	default:
@@ -205,7 +218,7 @@ int svc_rdma_xdr_decode_req(struct rpcrdma_msg *rmsgp, struct svc_rqst *rqstp)
 	 * chunk list and a reply chunk list.
 	 */
 	va = &rmsgp->rm_body.rm_chunks[0];
-	vaend = (__be32 *)((unsigned long)rmsgp + rqstp->rq_arg.len);
+	vaend = (__be32 *)((unsigned long)rmsgp + rq_arg->len);
 	va = decode_read_list(va, vaend);
 	if (!va) {
 		dprintk("svcrdma: failed to decode read list\n");
@@ -222,10 +235,9 @@ int svc_rdma_xdr_decode_req(struct rpcrdma_msg *rmsgp, struct svc_rqst *rqstp)
 		return -EINVAL;
 	}
 
-	rqstp->rq_arg.head[0].iov_base = va;
+	rq_arg->head[0].iov_base = va;
 	hdr_len = (unsigned long)va - (unsigned long)rmsgp;
-	rqstp->rq_arg.head[0].iov_len -= hdr_len;
-
+	rq_arg->head[0].iov_len -= hdr_len;
 	return hdr_len;
 }
 
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 1b72f35..c984b0a 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -636,7 +636,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 
 	/* Decode the RDMA header. */
 	rmsgp = (struct rpcrdma_msg *)rqstp->rq_arg.head[0].iov_base;
-	ret = svc_rdma_xdr_decode_req(rmsgp, rqstp);
+	ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg);
 	if (ret < 0)
 		goto out_err;
 	if (ret == 0)

[PATCH v2 9/9] svcrdma: Simplify the check for backward direction replies

[Chuck Lever]

Clean up: rq_arg.head[0] already points to the RPC header. No need
to walk down the RPC-over-RDMA header again.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |   31 ++++++++++---------------------
 1 file changed, 10 insertions(+), 21 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index c984b0a..f30a43b 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -549,35 +549,24 @@ static void rdma_read_complete(struct svc_rqst *rqstp,
 	rqstp->rq_arg.buflen = head->arg.buflen;
 }
 
-/* By convention, backchannel calls arrive via rdma_msg type
- * messages, and never populate the chunk lists. This makes
- * the RPC/RDMA header small and fixed in size, so it is
- * straightforward to check the RPC header's direction field.
+/* Currently, this implementation does not support chunks in the
+ * backward direction. Thus only RDMA_MSG bc replies are accepted.
  */
 static bool
-svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, struct rpcrdma_msg *rmsgp)
+svc_rdma_is_backchannel_reply(struct svc_xprt *xprt, struct rpcrdma_msg *rmsgp,
+			      struct xdr_buf *msgp)
 {
-	__be32 *p = (__be32 *)rmsgp;
+	__be32 *p = (__be32 *)msgp->head[0].iov_base;
 
+	/* Is there a backchannel transport associated with xprt? */
 	if (!xprt->xpt_bc_xprt)
 		return false;
-
+	/* Is there an RPC message in the inline buffer? */
 	if (rmsgp->rm_type != rdma_msg)
 		return false;
-	if (rmsgp->rm_body.rm_chunks[0] != xdr_zero)
-		return false;
-	if (rmsgp->rm_body.rm_chunks[1] != xdr_zero)
+	/* Is that message a Call or a Reply? */
+	if (p[1] != cpu_to_be32(RPC_REPLY))
 		return false;
-	if (rmsgp->rm_body.rm_chunks[2] != xdr_zero)
-		return false;
-
-	/* sanity */
-	if (p[7] != rmsgp->rm_xid)
-		return false;
-	/* call direction */
-	if (p[8] == cpu_to_be32(RPC_CALL))
-		return false;
-
 	return true;
 }
 
@@ -643,7 +632,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 		goto out_drop;
 	rqstp->rq_xprt_hlen = ret;
 
-	if (svc_rdma_is_backchannel_reply(xprt, rmsgp)) {
+	if (svc_rdma_is_backchannel_reply(xprt, rmsgp, &rqstp->rq_arg)) {
 		ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, rmsgp,
 					       &rqstp->rq_arg);
 		svc_rdma_put_context(ctxt, 0);

Re: [PATCH v2 0/9] NFS/RDMA server patches proposed for v4.7

[J. Bruce Fields]

On Wed, May 04, 2016 at 10:52:38AM -0400, Chuck Lever wrote:
> Shirley's server-side IPv6 patch, and a number of minor fixes and
> clean-ups found during code review.

Thanks, applying for 4.7.--b.

> 
> Available in the "nfsd-rdma-for-4.7" topic branch of this git repo:
> 
> git://git.linux-nfs.org/projects/cel/cel-2.6.git
> 
> Or for browsing:
> 
> http://git.linux-nfs.org/?p=cel/cel-2.6.git;a=log;h=refs/heads/nfsd-rdma-for-4.7
> 
> 
> Changes since v1:
> - Rebased on v4.6-rc6
> - Patch converting CQs to workqueue has been dropped for now
> - A number of clean-ups
> 
> ---
> 
> Chuck Lever (8):
>       svcrdma: Do not add XDR padding to xdr_buf page vector
>       svcrdma: svc_rdma_put_context() is invoked twice in Send error path
>       svcrdma: Remove superfluous line from rdma_read_chunks()
>       svcrdma: Post Receives only for forward channel requests
>       svcrdma: Drain QP before freeing svcrdma_xprt
>       svcrdma: Eliminate code duplication in svc_rdma_recvfrom()
>       svcrdma: Generalize svc_rdma_xdr_decode_req()
>       svcrdma: Simplify the check for backward direction replies
> 
> Shirley Ma (1):
>       svcrdma: Support IPv6 with NFS/RDMA
> 
> 
>  fs/nfsd/nfs3xdr.c                        |    2 -
>  include/linux/sunrpc/svc_rdma.h          |    2 -
>  net/sunrpc/xprtrdma/svc_rdma_marshal.c   |   32 ++++++++++-----
>  net/sunrpc/xprtrdma/svc_rdma_recvfrom.c  |   65 ++++++++----------------------
>  net/sunrpc/xprtrdma/svc_rdma_sendto.c    |   28 ++++++-------
>  net/sunrpc/xprtrdma/svc_rdma_transport.c |   17 +++++++-
>  6 files changed, 70 insertions(+), 76 deletions(-)
> 
> --
> Chuck Lever