diff options
Diffstat (limited to 'kernel/net/sunrpc/xprtrdma/fmr_ops.c')
-rw-r--r-- | kernel/net/sunrpc/xprtrdma/fmr_ops.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/kernel/net/sunrpc/xprtrdma/fmr_ops.c b/kernel/net/sunrpc/xprtrdma/fmr_ops.c new file mode 100644 index 000000000..302d4ebf6 --- /dev/null +++ b/kernel/net/sunrpc/xprtrdma/fmr_ops.c @@ -0,0 +1,208 @@ +/* + * 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) + +static int +fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, + struct rpcrdma_create_data_internal *cdata) +{ + return 0; +} + +/* 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); +} + +static int +fmr_op_init(struct rpcrdma_xprt *r_xprt) +{ + struct rpcrdma_buffer *buf = &r_xprt->rx_buf; + int mr_access_flags = IB_ACCESS_REMOTE_WRITE | IB_ACCESS_REMOTE_READ; + struct ib_fmr_attr fmr_attr = { + .max_pages = RPCRDMA_MAX_FMR_SGES, + .max_maps = 1, + .page_shift = PAGE_SHIFT + }; + struct ib_pd *pd = r_xprt->rx_ia.ri_pd; + struct rpcrdma_mw *r; + int i, rc; + + INIT_LIST_HEAD(&buf->rb_mws); + INIT_LIST_HEAD(&buf->rb_all); + + i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS; + dprintk("RPC: %s: initializing %d FMRs\n", __func__, i); + + while (i--) { + r = kzalloc(sizeof(*r), GFP_KERNEL); + if (!r) + return -ENOMEM; + + r->r.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr); + if (IS_ERR(r->r.fmr)) + goto out_fmr_err; + + list_add(&r->mw_list, &buf->rb_mws); + list_add(&r->mw_all, &buf->rb_all); + } + return 0; + +out_fmr_err: + rc = PTR_ERR(r->r.fmr); + dprintk("RPC: %s: ib_alloc_fmr status %i\n", __func__, rc); + kfree(r); + return rc; +} + +/* Use the ib_map_phys_fmr() verb to register a memory region + * for remote access via RDMA READ or RDMA WRITE. + */ +static int +fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, + int nsegs, bool writing) +{ + struct rpcrdma_ia *ia = &r_xprt->rx_ia; + struct ib_device *device = ia->ri_id->device; + enum dma_data_direction direction = rpcrdma_data_dir(writing); + struct rpcrdma_mr_seg *seg1 = seg; + struct rpcrdma_mw *mw = seg1->rl_mw; + u64 physaddrs[RPCRDMA_MAX_DATA_SEGS]; + int len, pageoff, i, rc; + + pageoff = offset_in_page(seg1->mr_offset); + seg1->mr_offset -= pageoff; /* start of page */ + seg1->mr_len += pageoff; + len = -pageoff; + if (nsegs > RPCRDMA_MAX_FMR_SGES) + nsegs = RPCRDMA_MAX_FMR_SGES; + for (i = 0; i < nsegs;) { + rpcrdma_map_one(device, seg, direction); + physaddrs[i] = seg->mr_dma; + len += seg->mr_len; + ++seg; + ++i; + /* Check for holes */ + if ((i < nsegs && offset_in_page(seg->mr_offset)) || + offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len)) + break; + } + + rc = ib_map_phys_fmr(mw->r.fmr, physaddrs, i, seg1->mr_dma); + if (rc) + goto out_maperr; + + seg1->mr_rkey = mw->r.fmr->rkey; + seg1->mr_base = seg1->mr_dma + pageoff; + seg1->mr_nsegs = i; + seg1->mr_len = len; + return i; + +out_maperr: + dprintk("RPC: %s: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n", + __func__, len, (unsigned long long)seg1->mr_dma, + pageoff, i, rc); + while (i--) + rpcrdma_unmap_one(device, --seg); + return rc; +} + +/* Use the ib_unmap_fmr() verb to prevent further remote + * access via RDMA READ or RDMA WRITE. + */ +static int +fmr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg) +{ + struct rpcrdma_ia *ia = &r_xprt->rx_ia; + struct rpcrdma_mr_seg *seg1 = seg; + struct ib_device *device; + int rc, nsegs = seg->mr_nsegs; + LIST_HEAD(l); + + list_add(&seg1->rl_mw->r.fmr->list, &l); + rc = ib_unmap_fmr(&l); + read_lock(&ia->ri_qplock); + device = ia->ri_id->device; + while (seg1->mr_nsegs--) + rpcrdma_unmap_one(device, seg++); + read_unlock(&ia->ri_qplock); + if (rc) + goto out_err; + return nsegs; + +out_err: + dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc); + return nsegs; +} + +/* After a disconnect, unmap all FMRs. + * + * This is invoked only in the transport connect worker in order + * to serialize with rpcrdma_register_fmr_external(). + */ +static void +fmr_op_reset(struct rpcrdma_xprt *r_xprt) +{ + struct rpcrdma_buffer *buf = &r_xprt->rx_buf; + struct rpcrdma_mw *r; + LIST_HEAD(list); + int rc; + + list_for_each_entry(r, &buf->rb_all, mw_all) + list_add(&r->r.fmr->list, &list); + + rc = ib_unmap_fmr(&list); + if (rc) + dprintk("RPC: %s: ib_unmap_fmr failed %i\n", + __func__, rc); +} + +static void +fmr_op_destroy(struct rpcrdma_buffer *buf) +{ + struct rpcrdma_mw *r; + int rc; + + while (!list_empty(&buf->rb_all)) { + r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all); + list_del(&r->mw_all); + rc = ib_dealloc_fmr(r->r.fmr); + if (rc) + dprintk("RPC: %s: ib_dealloc_fmr failed %i\n", + __func__, rc); + kfree(r); + } +} + +const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = { + .ro_map = fmr_op_map, + .ro_unmap = fmr_op_unmap, + .ro_open = fmr_op_open, + .ro_maxpages = fmr_op_maxpages, + .ro_init = fmr_op_init, + .ro_reset = fmr_op_reset, + .ro_destroy = fmr_op_destroy, + .ro_displayname = "fmr", +}; |