| /* |
| * 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). |
| */ |
| |
| #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) |
| |
| /* Access mode of externally registered pages */ |
| enum { |
| RPCRDMA_FMR_ACCESS_FLAGS = IB_ACCESS_REMOTE_WRITE | |
| IB_ACCESS_REMOTE_READ, |
| }; |
| |
| bool |
| fmr_is_supported(struct rpcrdma_ia *ia) |
| { |
| if (!ia->ri_device->alloc_fmr) { |
| pr_info("rpcrdma: 'fmr' mode is not supported by device %s\n", |
| ia->ri_device->name); |
| return false; |
| } |
| return true; |
| } |
| |
| static int |
| fmr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *mw) |
| { |
| static struct ib_fmr_attr fmr_attr = { |
| .max_pages = RPCRDMA_MAX_FMR_SGES, |
| .max_maps = 1, |
| .page_shift = PAGE_SHIFT |
| }; |
| |
| mw->fmr.fm_physaddrs = kcalloc(RPCRDMA_MAX_FMR_SGES, |
| sizeof(u64), GFP_KERNEL); |
| if (!mw->fmr.fm_physaddrs) |
| goto out_free; |
| |
| mw->mw_sg = kcalloc(RPCRDMA_MAX_FMR_SGES, |
| sizeof(*mw->mw_sg), GFP_KERNEL); |
| if (!mw->mw_sg) |
| goto out_free; |
| |
| sg_init_table(mw->mw_sg, RPCRDMA_MAX_FMR_SGES); |
| |
| mw->fmr.fm_mr = ib_alloc_fmr(ia->ri_pd, RPCRDMA_FMR_ACCESS_FLAGS, |
| &fmr_attr); |
| if (IS_ERR(mw->fmr.fm_mr)) |
| goto out_fmr_err; |
| |
| return 0; |
| |
| out_fmr_err: |
| dprintk("RPC: %s: ib_alloc_fmr returned %ld\n", __func__, |
| PTR_ERR(mw->fmr.fm_mr)); |
| |
| out_free: |
| kfree(mw->mw_sg); |
| kfree(mw->fmr.fm_physaddrs); |
| return -ENOMEM; |
| } |
| |
| static int |
| __fmr_unmap(struct rpcrdma_mw *mw) |
| { |
| LIST_HEAD(l); |
| int rc; |
| |
| list_add(&mw->fmr.fm_mr->list, &l); |
| rc = ib_unmap_fmr(&l); |
| list_del(&mw->fmr.fm_mr->list); |
| return rc; |
| } |
| |
| static void |
| fmr_op_release_mr(struct rpcrdma_mw *r) |
| { |
| LIST_HEAD(unmap_list); |
| int rc; |
| |
| /* Ensure MW is not on any rl_registered list */ |
| if (!list_empty(&r->mw_list)) |
| list_del(&r->mw_list); |
| |
| kfree(r->fmr.fm_physaddrs); |
| kfree(r->mw_sg); |
| |
| /* In case this one was left mapped, try to unmap it |
| * to prevent dealloc_fmr from failing with EBUSY |
| */ |
| rc = __fmr_unmap(r); |
| if (rc) |
| pr_err("rpcrdma: final ib_unmap_fmr for %p failed %i\n", |
| r, rc); |
| |
| rc = ib_dealloc_fmr(r->fmr.fm_mr); |
| if (rc) |
| pr_err("rpcrdma: final ib_dealloc_fmr for %p returned %i\n", |
| r, rc); |
| |
| kfree(r); |
| } |
| |
| /* Reset of a single FMR. |
| */ |
| static void |
| fmr_op_recover_mr(struct rpcrdma_mw *mw) |
| { |
| struct rpcrdma_xprt *r_xprt = mw->mw_xprt; |
| int rc; |
| |
| /* ORDER: invalidate first */ |
| rc = __fmr_unmap(mw); |
| |
| /* ORDER: then DMA unmap */ |
| ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, |
| mw->mw_sg, mw->mw_nents, mw->mw_dir); |
| if (rc) |
| goto out_release; |
| |
| rpcrdma_put_mw(r_xprt, mw); |
| r_xprt->rx_stats.mrs_recovered++; |
| return; |
| |
| out_release: |
| pr_err("rpcrdma: FMR reset failed (%d), %p released\n", rc, mw); |
| r_xprt->rx_stats.mrs_orphaned++; |
| |
| spin_lock(&r_xprt->rx_buf.rb_mwlock); |
| list_del(&mw->mw_all); |
| spin_unlock(&r_xprt->rx_buf.rb_mwlock); |
| |
| fmr_op_release_mr(mw); |
| } |
| |
| static int |
| fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, |
| struct rpcrdma_create_data_internal *cdata) |
| { |
| ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS / |
| RPCRDMA_MAX_FMR_SGES); |
| 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_HDR_SEGS * RPCRDMA_MAX_FMR_SGES); |
| } |
| |
| /* Use the ib_map_phys_fmr() verb to register a memory region |
| * for remote access via RDMA READ or RDMA WRITE. |
| */ |
| static struct rpcrdma_mr_seg * |
| fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, |
| int nsegs, bool writing, struct rpcrdma_mw **out) |
| { |
| struct rpcrdma_mr_seg *seg1 = seg; |
| int len, pageoff, i, rc; |
| struct rpcrdma_mw *mw; |
| u64 *dma_pages; |
| |
| mw = rpcrdma_get_mw(r_xprt); |
| if (!mw) |
| return ERR_PTR(-ENOBUFS); |
| |
| 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;) { |
| if (seg->mr_page) |
| sg_set_page(&mw->mw_sg[i], |
| seg->mr_page, |
| seg->mr_len, |
| offset_in_page(seg->mr_offset)); |
| else |
| sg_set_buf(&mw->mw_sg[i], seg->mr_offset, |
| seg->mr_len); |
| 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; |
| } |
| mw->mw_dir = rpcrdma_data_dir(writing); |
| |
| mw->mw_nents = ib_dma_map_sg(r_xprt->rx_ia.ri_device, |
| mw->mw_sg, i, mw->mw_dir); |
| if (!mw->mw_nents) |
| goto out_dmamap_err; |
| |
| for (i = 0, dma_pages = mw->fmr.fm_physaddrs; i < mw->mw_nents; i++) |
| dma_pages[i] = sg_dma_address(&mw->mw_sg[i]); |
| rc = ib_map_phys_fmr(mw->fmr.fm_mr, dma_pages, mw->mw_nents, |
| dma_pages[0]); |
| if (rc) |
| goto out_maperr; |
| |
| mw->mw_handle = mw->fmr.fm_mr->rkey; |
| mw->mw_length = len; |
| mw->mw_offset = dma_pages[0] + pageoff; |
| |
| *out = mw; |
| return seg; |
| |
| out_dmamap_err: |
| pr_err("rpcrdma: failed to DMA map sg %p sg_nents %d\n", |
| mw->mw_sg, i); |
| rpcrdma_put_mw(r_xprt, mw); |
| return ERR_PTR(-EIO); |
| |
| out_maperr: |
| pr_err("rpcrdma: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n", |
| len, (unsigned long long)dma_pages[0], |
| pageoff, mw->mw_nents, rc); |
| ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, |
| mw->mw_sg, mw->mw_nents, mw->mw_dir); |
| rpcrdma_put_mw(r_xprt, mw); |
| return ERR_PTR(-EIO); |
| } |
| |
| /* 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. |
| * |
| * Caller ensures that @mws is not empty before the call. This |
| * function empties the list. |
| */ |
| static void |
| fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct list_head *mws) |
| { |
| struct rpcrdma_mw *mw; |
| LIST_HEAD(unmap_list); |
| int rc; |
| |
| /* 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 FMR. |
| */ |
| list_for_each_entry(mw, mws, mw_list) { |
| dprintk("RPC: %s: unmapping fmr %p\n", |
| __func__, &mw->fmr); |
| list_add_tail(&mw->fmr.fm_mr->list, &unmap_list); |
| } |
| r_xprt->rx_stats.local_inv_needed++; |
| rc = ib_unmap_fmr(&unmap_list); |
| if (rc) |
| goto out_reset; |
| |
| /* ORDER: Now DMA unmap all of the req's MRs, and return |
| * them to the free MW list. |
| */ |
| while (!list_empty(mws)) { |
| mw = rpcrdma_pop_mw(mws); |
| dprintk("RPC: %s: DMA unmapping fmr %p\n", |
| __func__, &mw->fmr); |
| list_del(&mw->fmr.fm_mr->list); |
| ib_dma_unmap_sg(r_xprt->rx_ia.ri_device, |
| mw->mw_sg, mw->mw_nents, mw->mw_dir); |
| rpcrdma_put_mw(r_xprt, mw); |
| } |
| |
| return; |
| |
| out_reset: |
| pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc); |
| |
| while (!list_empty(mws)) { |
| mw = rpcrdma_pop_mw(mws); |
| list_del(&mw->fmr.fm_mr->list); |
| fmr_op_recover_mr(mw); |
| } |
| } |
| |
| const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = { |
| .ro_map = fmr_op_map, |
| .ro_unmap_sync = fmr_op_unmap_sync, |
| .ro_recover_mr = fmr_op_recover_mr, |
| .ro_open = fmr_op_open, |
| .ro_maxpages = fmr_op_maxpages, |
| .ro_init_mr = fmr_op_init_mr, |
| .ro_release_mr = fmr_op_release_mr, |
| .ro_displayname = "fmr", |
| .ro_send_w_inv_ok = 0, |
| }; |