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: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Steve Wise 2014-09-23 17:11:22 -05:00 committed by J. Bruce Fields
parent 0162ac2b97
commit 7e5be28827
2 changed files with 8 additions and 1 deletions

View File

@ -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,
};

View File

@ -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 */