linux_old1/net/sunrpc/xprtrdma/fmr_ops.c

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/*
* Copyright (c) 2015 Oracle. All rights reserved.
* Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
*/
/* Lightweight memory registration using Fast Memory Regions (FMR).
* Referred to sometimes as MTHCAFMR mode.
*
* FMR uses synchronous memory registration and deregistration.
* FMR registration is known to be fast, but FMR deregistration
* can take tens of usecs to complete.
*/
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
/* Maximum scatter/gather per FMR */
#define RPCRDMA_MAX_FMR_SGES (64)
/* FMR mode conveys up to 64 pages of payload per chunk segment.
*/
static size_t
fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)
{
return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
rpcrdma_max_segments(r_xprt) * RPCRDMA_MAX_FMR_SGES);
}
const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
.ro_maxpages = fmr_op_maxpages,
.ro_displayname = "fmr",
};