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Commit 7e5be288 authored by Steve Wise's avatar Steve Wise Committed by J. Bruce Fields
Browse files

svcrdma: advertise the correct max payload 



Svcrdma currently advertises 1MB, which is too large.  The correct value
is the minimum of RPCSVC_MAXPAYLOAD and 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: default avatarSteve Wise <swise@opengridcomputing.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 0162ac2b

net/sunrpc/xprtrdma/svc_rdma_transport.c

+1 −1
Original line number Diff line number Diff line
@@ -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,

};

net/sunrpc/xprtrdma/xprt_rdma.h

+7 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#include <linux/sunrpc/clnt.h> 		/* rpc_xprt */

#include <linux/sunrpc/rpc_rdma.h> 	/* RPC/RDMA protocol */

#include <linux/sunrpc/xprtrdma.h> 	/* xprt parameters */

#include <linux/sunrpc/svc.h>		/* RPCSVC_MAXPAYLOAD */



#define RDMA_RESOLVE_TIMEOUT	(5000)	/* 5 seconds */

#define RDMA_CONNECT_RETRY_MAX	(2)	/* retries if no listener backlog */
@@ -392,4 +393,10 @@ extern struct kmem_cache *svc_rdma_ctxt_cachep; 
/* Workqueue created in svc_rdma.c */

extern struct workqueue_struct *svc_rdma_wq;



#if RPCSVC_MAXPAYLOAD < (RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT)

#define RPCSVC_MAXPAYLOAD_RDMA RPCSVC_MAXPAYLOAD

#else

#define RPCSVC_MAXPAYLOAD_RDMA (RPCRDMA_MAX_DATA_SEGS << PAGE_SHIFT)

#endif



#endif				/* _LINUX_SUNRPC_XPRT_RDMA_H */