Commit 6946f823 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

xprtrdma: Fix ri_max_segs and the result of ro_maxpages 



With certain combinations of krb5i/p, MR size, and r/wsize, I/O can
fail with EMSGSIZE. This is because the calculated value of
ri_max_segs (the max number of MRs per RPC) exceeded
RPCRDMA_MAX_HDR_SEGS, which caused Read or Write list encoding to
walk off the end of the transport header.

Once that was addressed, the ro_maxpages result has to be corrected
to account for the number of MRs needed for Reply chunks, which is
2 MRs smaller than a normal Read or Write chunk.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 0c0829bc

net/sunrpc/xprtrdma/fmr_ops.c

+5 −2
Original line number Diff line number Diff line
@@ -176,7 +176,10 @@ fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, 


	ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /

				RPCRDMA_MAX_FMR_SGES);

	ia->ri_max_segs += 2;	/* segments for head and tail buffers */

	/* Reply chunks require segments for head and tail buffers */

	ia->ri_max_segs += 2;

	if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS)

		ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS;

	return 0;

}
@@ -186,7 +189,7 @@ static size_t 
fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)

{

	return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,

		     RPCRDMA_MAX_HDR_SEGS * RPCRDMA_MAX_FMR_SGES);

		     (r_xprt->rx_ia.ri_max_segs - 2) * RPCRDMA_MAX_FMR_SGES);

}



/* Use the ib_map_phys_fmr() verb to register a memory region

net/sunrpc/xprtrdma/frwr_ops.c

+5 −2
Original line number Diff line number Diff line
@@ -244,7 +244,10 @@ frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, 


	ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /

				ia->ri_max_frwr_depth);

	ia->ri_max_segs += 2;	/* segments for head and tail buffers */

	/* Reply chunks require segments for head and tail buffers */

	ia->ri_max_segs += 2;

	if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS)

		ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS;

	return 0;

}
@@ -257,7 +260,7 @@ frwr_op_maxpages(struct rpcrdma_xprt *r_xprt) 
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;



	return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,

		     RPCRDMA_MAX_HDR_SEGS * ia->ri_max_frwr_depth);

		     (ia->ri_max_segs - 2) * ia->ri_max_frwr_depth);

}



static void

net/sunrpc/xprtrdma/transport.c

+4 −2
Original line number Diff line number Diff line
@@ -703,8 +703,10 @@ xprt_rdma_free(struct rpc_task *task) 
 *	%-ENOTCONN if the caller should reconnect and call again

 *	%-EAGAIN if the caller should call again

 *	%-ENOBUFS if the caller should call again after a delay

 *	%-EIO if a permanent error occurred and the request was not

 *		sent. Do not try to send this message again.

 *	%-EMSGSIZE if encoding ran out of buffer space. The request

 *		was not sent. Do not try to send this message again.

 *	%-EIO if an I/O error occurred. The request was not sent.

 *		Do not try to send this message again.

 */

static int

xprt_rdma_send_request(struct rpc_rqst *rqst)

CRA Git | Maintained and supported by SUSTech CRA and CCSE