| /* |
| * 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. |
| */ |
| |
| /* Normal operation |
| * |
| * A Memory Region is prepared for RDMA READ or WRITE using the |
| * ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is |
| * finished, the Memory Region is unmapped using the ib_unmap_fmr |
| * verb (fmr_op_unmap). |
| */ |
| |
| /* Transport recovery |
| * |
| * After a transport reconnect, fmr_op_map re-uses the MR already |
| * allocated for the RPC, but generates a fresh rkey then maps the |
| * MR again. This process is synchronous. |
| */ |
| |
| #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; |
| |
| spin_lock_init(&buf->rb_mwlock); |
| INIT_LIST_HEAD(&buf->rb_mws); |
| INIT_LIST_HEAD(&buf->rb_all); |
| |
| i = max_t(int, RPCRDMA_MAX_DATA_SEGS / RPCRDMA_MAX_FMR_SGES, 1); |
| i += 2; /* head + tail */ |
| i *= buf->rb_max_requests; /* one set for each RPC slot */ |
| dprintk("RPC: %s: initalizing %d FMRs\n", __func__, i); |
| |
| rc = -ENOMEM; |
| while (i--) { |
| r = kzalloc(sizeof(*r), GFP_KERNEL); |
| if (!r) |
| goto out; |
| |
| r->fmr.physaddrs = kmalloc(RPCRDMA_MAX_FMR_SGES * |
| sizeof(u64), GFP_KERNEL); |
| if (!r->fmr.physaddrs) |
| goto out_free; |
| |
| r->fmr.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr); |
| if (IS_ERR(r->fmr.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->fmr.fmr); |
| dprintk("RPC: %s: ib_alloc_fmr status %i\n", __func__, rc); |
| kfree(r->fmr.physaddrs); |
| out_free: |
| kfree(r); |
| out: |
| return rc; |
| } |
| |
| static int |
| __fmr_unmap(struct rpcrdma_mw *r) |
| { |
| LIST_HEAD(l); |
| |
| list_add(&r->fmr.fmr->list, &l); |
| return ib_unmap_fmr(&l); |
| } |
| |
| /* 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_device; |
| enum dma_data_direction direction = rpcrdma_data_dir(writing); |
| struct rpcrdma_mr_seg *seg1 = seg; |
| int len, pageoff, i, rc; |
| struct rpcrdma_mw *mw; |
| |
| mw = seg1->rl_mw; |
| seg1->rl_mw = NULL; |
| if (!mw) { |
| mw = rpcrdma_get_mw(r_xprt); |
| if (!mw) |
| return -ENOMEM; |
| } else { |
| /* this is a retransmit; generate a fresh rkey */ |
| rc = __fmr_unmap(mw); |
| if (rc) |
| return 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); |
| mw->fmr.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->fmr.fmr, mw->fmr.physaddrs, |
| i, seg1->mr_dma); |
| if (rc) |
| goto out_maperr; |
| |
| seg1->rl_mw = mw; |
| seg1->mr_rkey = mw->fmr.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; |
| } |
| |
| static void |
| __fmr_dma_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg) |
| { |
| struct ib_device *device = r_xprt->rx_ia.ri_device; |
| struct rpcrdma_mw *mw = seg->rl_mw; |
| int nsegs = seg->mr_nsegs; |
| |
| seg->rl_mw = NULL; |
| |
| while (nsegs--) |
| rpcrdma_unmap_one(device, seg++); |
| |
| rpcrdma_put_mw(r_xprt, mw); |
| } |
| |
| /* Invalidate all memory regions that were registered for "req". |
| * |
| * Sleeps until it is safe for the host CPU to access the |
| * previously mapped memory regions. |
| */ |
| static void |
| fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) |
| { |
| struct rpcrdma_mr_seg *seg; |
| unsigned int i, nchunks; |
| struct rpcrdma_mw *mw; |
| LIST_HEAD(unmap_list); |
| int rc; |
| |
| dprintk("RPC: %s: req %p\n", __func__, req); |
| |
| /* ORDER: Invalidate all of the req's MRs first |
| * |
| * ib_unmap_fmr() is slow, so use a single call instead |
| * of one call per mapped MR. |
| */ |
| for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) { |
| seg = &req->rl_segments[i]; |
| mw = seg->rl_mw; |
| |
| list_add(&mw->fmr.fmr->list, &unmap_list); |
| |
| i += seg->mr_nsegs; |
| } |
| rc = ib_unmap_fmr(&unmap_list); |
| if (rc) |
| pr_warn("%s: ib_unmap_fmr failed (%i)\n", __func__, rc); |
| |
| /* ORDER: Now DMA unmap all of the req's MRs, and return |
| * them to the free MW list. |
| */ |
| for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) { |
| seg = &req->rl_segments[i]; |
| |
| __fmr_dma_unmap(r_xprt, seg); |
| |
| i += seg->mr_nsegs; |
| seg->mr_nsegs = 0; |
| } |
| |
| req->rl_nchunks = 0; |
| } |
| |
| /* 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 rpcrdma_mw *mw = seg1->rl_mw; |
| int rc, nsegs = seg->mr_nsegs; |
| |
| dprintk("RPC: %s: FMR %p\n", __func__, mw); |
| |
| seg1->rl_mw = NULL; |
| while (seg1->mr_nsegs--) |
| rpcrdma_unmap_one(ia->ri_device, seg++); |
| rc = __fmr_unmap(mw); |
| if (rc) |
| goto out_err; |
| rpcrdma_put_mw(r_xprt, mw); |
| return nsegs; |
| |
| out_err: |
| /* The FMR is abandoned, but remains in rb_all. fmr_op_destroy |
| * will attempt to release it when the transport is destroyed. |
| */ |
| dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc); |
| return nsegs; |
| } |
| |
| 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); |
| kfree(r->fmr.physaddrs); |
| |
| rc = ib_dealloc_fmr(r->fmr.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_sync = fmr_op_unmap_sync, |
| .ro_unmap = fmr_op_unmap, |
| .ro_open = fmr_op_open, |
| .ro_maxpages = fmr_op_maxpages, |
| .ro_init = fmr_op_init, |
| .ro_destroy = fmr_op_destroy, |
| .ro_displayname = "fmr", |
| }; |