--- /dev/null
+/*
+ * 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",
+};
Code Review / kvmfornfv.git / blobdiff