v4.19.13 snapshot.
diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c
new file mode 100644
index 0000000..0f7c465
--- /dev/null
+++ b/net/sunrpc/xprtrdma/fmr_ops.c
@@ -0,0 +1,348 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2015, 2017 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 <linux/sunrpc/svc_rdma.h>
+
+#include "xprt_rdma.h"
+#include <trace/events/rpcrdma.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_mr *mr)
+{
+ static struct ib_fmr_attr fmr_attr = {
+ .max_pages = RPCRDMA_MAX_FMR_SGES,
+ .max_maps = 1,
+ .page_shift = PAGE_SHIFT
+ };
+
+ mr->fmr.fm_physaddrs = kcalloc(RPCRDMA_MAX_FMR_SGES,
+ sizeof(u64), GFP_KERNEL);
+ if (!mr->fmr.fm_physaddrs)
+ goto out_free;
+
+ mr->mr_sg = kcalloc(RPCRDMA_MAX_FMR_SGES,
+ sizeof(*mr->mr_sg), GFP_KERNEL);
+ if (!mr->mr_sg)
+ goto out_free;
+
+ sg_init_table(mr->mr_sg, RPCRDMA_MAX_FMR_SGES);
+
+ mr->fmr.fm_mr = ib_alloc_fmr(ia->ri_pd, RPCRDMA_FMR_ACCESS_FLAGS,
+ &fmr_attr);
+ if (IS_ERR(mr->fmr.fm_mr))
+ goto out_fmr_err;
+
+ INIT_LIST_HEAD(&mr->mr_list);
+ return 0;
+
+out_fmr_err:
+ dprintk("RPC: %s: ib_alloc_fmr returned %ld\n", __func__,
+ PTR_ERR(mr->fmr.fm_mr));
+
+out_free:
+ kfree(mr->mr_sg);
+ kfree(mr->fmr.fm_physaddrs);
+ return -ENOMEM;
+}
+
+static int
+__fmr_unmap(struct rpcrdma_mr *mr)
+{
+ LIST_HEAD(l);
+ int rc;
+
+ list_add(&mr->fmr.fm_mr->list, &l);
+ rc = ib_unmap_fmr(&l);
+ list_del(&mr->fmr.fm_mr->list);
+ return rc;
+}
+
+static void
+fmr_op_release_mr(struct rpcrdma_mr *mr)
+{
+ LIST_HEAD(unmap_list);
+ int rc;
+
+ kfree(mr->fmr.fm_physaddrs);
+ kfree(mr->mr_sg);
+
+ /* In case this one was left mapped, try to unmap it
+ * to prevent dealloc_fmr from failing with EBUSY
+ */
+ rc = __fmr_unmap(mr);
+ if (rc)
+ pr_err("rpcrdma: final ib_unmap_fmr for %p failed %i\n",
+ mr, rc);
+
+ rc = ib_dealloc_fmr(mr->fmr.fm_mr);
+ if (rc)
+ pr_err("rpcrdma: final ib_dealloc_fmr for %p returned %i\n",
+ mr, rc);
+
+ kfree(mr);
+}
+
+/* Reset of a single FMR.
+ */
+static void
+fmr_op_recover_mr(struct rpcrdma_mr *mr)
+{
+ struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
+ int rc;
+
+ /* ORDER: invalidate first */
+ rc = __fmr_unmap(mr);
+ if (rc)
+ goto out_release;
+
+ /* ORDER: then DMA unmap */
+ rpcrdma_mr_unmap_and_put(mr);
+
+ r_xprt->rx_stats.mrs_recovered++;
+ return;
+
+out_release:
+ pr_err("rpcrdma: FMR reset failed (%d), %p released\n", rc, mr);
+ r_xprt->rx_stats.mrs_orphaned++;
+
+ trace_xprtrdma_dma_unmap(mr);
+ ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
+ mr->mr_sg, mr->mr_nents, mr->mr_dir);
+
+ spin_lock(&r_xprt->rx_buf.rb_mrlock);
+ list_del(&mr->mr_all);
+ spin_unlock(&r_xprt->rx_buf.rb_mrlock);
+
+ fmr_op_release_mr(mr);
+}
+
+/* On success, sets:
+ * ep->rep_attr.cap.max_send_wr
+ * ep->rep_attr.cap.max_recv_wr
+ * cdata->max_requests
+ * ia->ri_max_segs
+ */
+static int
+fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
+ struct rpcrdma_create_data_internal *cdata)
+{
+ int max_qp_wr;
+
+ max_qp_wr = ia->ri_device->attrs.max_qp_wr;
+ max_qp_wr -= RPCRDMA_BACKWARD_WRS;
+ max_qp_wr -= 1;
+ if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)
+ return -ENOMEM;
+ if (cdata->max_requests > max_qp_wr)
+ cdata->max_requests = max_qp_wr;
+ ep->rep_attr.cap.max_send_wr = cdata->max_requests;
+ ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
+ ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
+ ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
+
+ 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_mr **out)
+{
+ struct rpcrdma_mr_seg *seg1 = seg;
+ int len, pageoff, i, rc;
+ struct rpcrdma_mr *mr;
+ u64 *dma_pages;
+
+ mr = rpcrdma_mr_get(r_xprt);
+ if (!mr)
+ return ERR_PTR(-EAGAIN);
+
+ 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(&mr->mr_sg[i],
+ seg->mr_page,
+ seg->mr_len,
+ offset_in_page(seg->mr_offset));
+ else
+ sg_set_buf(&mr->mr_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;
+ }
+ mr->mr_dir = rpcrdma_data_dir(writing);
+
+ mr->mr_nents = ib_dma_map_sg(r_xprt->rx_ia.ri_device,
+ mr->mr_sg, i, mr->mr_dir);
+ if (!mr->mr_nents)
+ goto out_dmamap_err;
+ trace_xprtrdma_dma_map(mr);
+
+ for (i = 0, dma_pages = mr->fmr.fm_physaddrs; i < mr->mr_nents; i++)
+ dma_pages[i] = sg_dma_address(&mr->mr_sg[i]);
+ rc = ib_map_phys_fmr(mr->fmr.fm_mr, dma_pages, mr->mr_nents,
+ dma_pages[0]);
+ if (rc)
+ goto out_maperr;
+
+ mr->mr_handle = mr->fmr.fm_mr->rkey;
+ mr->mr_length = len;
+ mr->mr_offset = dma_pages[0] + pageoff;
+
+ *out = mr;
+ return seg;
+
+out_dmamap_err:
+ pr_err("rpcrdma: failed to DMA map sg %p sg_nents %d\n",
+ mr->mr_sg, i);
+ rpcrdma_mr_put(mr);
+ 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, mr->mr_nents, rc);
+ rpcrdma_mr_unmap_and_put(mr);
+ return ERR_PTR(-EIO);
+}
+
+/* Post Send WR containing the RPC Call message.
+ */
+static int
+fmr_op_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
+{
+ return ib_post_send(ia->ri_id->qp, &req->rl_sendctx->sc_wr, NULL);
+}
+
+/* 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 @mrs 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 *mrs)
+{
+ struct rpcrdma_mr *mr;
+ 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(mr, mrs, mr_list) {
+ dprintk("RPC: %s: unmapping fmr %p\n",
+ __func__, &mr->fmr);
+ trace_xprtrdma_localinv(mr);
+ list_add_tail(&mr->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(mrs)) {
+ mr = rpcrdma_mr_pop(mrs);
+ list_del(&mr->fmr.fm_mr->list);
+ rpcrdma_mr_unmap_and_put(mr);
+ }
+
+ return;
+
+out_reset:
+ pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc);
+
+ while (!list_empty(mrs)) {
+ mr = rpcrdma_mr_pop(mrs);
+ list_del(&mr->fmr.fm_mr->list);
+ fmr_op_recover_mr(mr);
+ }
+}
+
+const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
+ .ro_map = fmr_op_map,
+ .ro_send = fmr_op_send,
+ .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,
+};