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* [PATCH] svcrdma: Advertise the correct max payload
@ 2014-09-22 18:36 ` Steve Wise
  0 siblings, 0 replies; 14+ messages in thread
From: Steve Wise @ 2014-09-22 18:36 UTC (permalink / raw)
  To: bfields; +Cc: linux-nfs, linux-rdma

Svcrdma currently advertises 1MB, which is too large.  The correct value
is the max scatter-gather allowed in an NFSRDMA IO chunk * the host page
size. This bug is usually benign because the Linux X64 NFSRDMA client
correctly limits the payload size to the correct value (64*4096 = 256KB).
But if the Linux client is PPC64 with a 64KB page size, then the client
will indeed use a payload size that will overflow the server.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
---

 net/sunrpc/xprtrdma/svc_rdma_transport.c |    2 +-
 net/sunrpc/xprtrdma/xprt_rdma.h          |    2 ++
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 374feb4..4e61880 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -91,7 +91,7 @@ struct svc_xprt_class svc_rdma_class = {
 	.xcl_name = "rdma",
 	.xcl_owner = THIS_MODULE,
 	.xcl_ops = &svc_rdma_ops,
-	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_RDMA,
 	.xcl_ident = XPRT_TRANSPORT_RDMA,
 };
 
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index c419498..467a77c 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -392,4 +392,6 @@ extern struct kmem_cache *svc_rdma_ctxt_cachep;
 /* Workqueue created in svc_rdma.c */
 extern struct workqueue_struct *svc_rdma_wq;
 
+#define RPCSVC_MAXPAYLOAD_RDMA	(RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT)
+
 #endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */


^ permalink raw reply related	[flat|nested] 14+ messages in thread

end of thread, other threads:[~2014-09-22 19:16 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-09-22 18:36 [PATCH] svcrdma: Advertise the correct max payload Steve Wise
2014-09-22 18:36 ` Steve Wise
2014-09-22 18:39 ` J. Bruce Fields
2014-09-22 18:39   ` J. Bruce Fields
2014-09-22 18:42   ` Steve Wise
2014-09-22 18:42     ` Steve Wise
2014-09-22 18:55     ` J. Bruce Fields
2014-09-22 18:55       ` J. Bruce Fields
2014-09-22 19:12       ` Steve Wise
2014-09-22 19:12         ` Steve Wise
2014-09-22 19:16       ` Chuck Lever
2014-09-22 19:16         ` Chuck Lever
2014-09-22 18:47   ` Chuck Lever
2014-09-22 18:47     ` Chuck Lever

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