[PATCH v2 12/26] xprtrdma: Port to new memory registration API

[Sagi Grimberg <sagig@mellanox.com>]

Instead of maintaining a fastreg page list, keep an sg table
and convert an array of pages to a sg list. Then call ib_map_mr_sg
and construct ib_reg_wr.

Note that the next step would be to have NFS work with sg lists
as it maps well to sk_frags (see comment from hch
http://marc.info/?l=linux-rdma&m=143677002622296&w=2).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Acked-by: Christoph Hellwig <hch@lst.de>
---
 net/sunrpc/xprtrdma/frwr_ops.c  | 113 +++++++++++++++++++++++-----------------
 net/sunrpc/xprtrdma/xprt_rdma.h |   3 +-
 2 files changed, 68 insertions(+), 48 deletions(-)

diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 0d2f46f600b6..b80a82149977 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -151,9 +151,13 @@ __frwr_init(struct rpcrdma_mw *r, struct ib_pd *pd, struct ib_device *device,
 	f->fr_mr = ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, depth);
 	if (IS_ERR(f->fr_mr))
 		goto out_mr_err;
-	f->fr_pgl = ib_alloc_fast_reg_page_list(device, depth);
-	if (IS_ERR(f->fr_pgl))
+
+	f->sg = kcalloc(depth, sizeof(*f->sg), GFP_KERNEL);
+	if (!f->sg)
 		goto out_list_err;
+
+	sg_init_table(f->sg, depth);
+
 	return 0;
 
 out_mr_err:
@@ -163,7 +167,7 @@ out_mr_err:
 	return rc;
 
 out_list_err:
-	rc = PTR_ERR(f->fr_pgl);
+	rc = -ENOMEM;
 	dprintk("RPC:       %s: ib_alloc_fast_reg_page_list status %i\n",
 		__func__, rc);
 	ib_dereg_mr(f->fr_mr);
@@ -179,7 +183,7 @@ __frwr_release(struct rpcrdma_mw *r)
 	if (rc)
 		dprintk("RPC:       %s: ib_dereg_mr status %i\n",
 			__func__, rc);
-	ib_free_fast_reg_page_list(r->r.frmr.fr_pgl);
+	kfree(r->r.frmr.sg);
 }
 
 static int
@@ -312,14 +316,11 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
 	struct rpcrdma_mw *mw;
 	struct rpcrdma_frmr *frmr;
 	struct ib_mr *mr;
-	struct ib_fast_reg_wr fastreg_wr;
+	struct ib_reg_wr reg_wr;
 	struct ib_send_wr *bad_wr;
+	unsigned int dma_nents;
 	u8 key;
-	int len, pageoff;
-	int i, rc;
-	int seg_len;
-	u64 pa;
-	int page_no;
+	int i, rc, len, n;
 
 	mw = seg1->rl_mw;
 	seg1->rl_mw = NULL;
@@ -332,64 +333,81 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
 	} while (mw->r.frmr.fr_state != FRMR_IS_INVALID);
 	frmr = &mw->r.frmr;
 	frmr->fr_state = FRMR_IS_VALID;
+	mr = frmr->fr_mr;
 
-	pageoff = offset_in_page(seg1->mr_offset);
-	seg1->mr_offset -= pageoff;	/* start of page */
-	seg1->mr_len += pageoff;
-	len = -pageoff;
 	if (nsegs > ia->ri_max_frmr_depth)
 		nsegs = ia->ri_max_frmr_depth;
 
-	for (page_no = i = 0; i < nsegs;) {
-		rpcrdma_map_one(device, seg, direction);
-		pa = seg->mr_dma;
-		for (seg_len = seg->mr_len; seg_len > 0; seg_len -= PAGE_SIZE) {
-			frmr->fr_pgl->page_list[page_no++] = pa;
-			pa += PAGE_SIZE;
-		}
+	for (len = 0, i = 0; i < nsegs;) {
+		if (seg->mr_page)
+			sg_set_page(&frmr->sg[i],
+				    seg->mr_page,
+				    seg->mr_len,
+				    offset_in_page(seg->mr_offset));
+		else
+			sg_set_buf(&frmr->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;
 	}
+	frmr->sg_nents = i;
+
+	dma_nents = ib_dma_map_sg(device, frmr->sg, frmr->sg_nents, direction);
+	if (!dma_nents) {
+		pr_err("RPC:       %s: failed to dma map sg %p sg_nents %d\n",
+		       __func__, frmr->sg, frmr->sg_nents);
+		return -ENOMEM;
+	}
+
+	n = ib_map_mr_sg(mr, frmr->sg, frmr->sg_nents, PAGE_SIZE);
+	if (unlikely(n != frmr->sg_nents)) {
+		pr_err("RPC:       %s: failed to map mr %p (%d/%d)\n",
+		       __func__, frmr->fr_mr, n, frmr->sg_nents);
+		rc = n < 0 ? n : -EINVAL;
+		goto out_senderr;
+	}
+
 	dprintk("RPC:       %s: Using frmr %p to map %d segments (%d bytes)\n",
-		__func__, mw, i, len);
-
-	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
-	fastreg_wr.wr.wr_id = (unsigned long)(void *)mw;
-	fastreg_wr.wr.opcode = IB_WR_FAST_REG_MR;
-	fastreg_wr.iova_start = seg1->mr_dma + pageoff;
-	fastreg_wr.page_list = frmr->fr_pgl;
-	fastreg_wr.page_shift = PAGE_SHIFT;
-	fastreg_wr.page_list_len = page_no;
-	fastreg_wr.length = len;
-	fastreg_wr.access_flags = writing ?
-				IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
-				IB_ACCESS_REMOTE_READ;
-	mr = frmr->fr_mr;
+		__func__, mw, frmr->sg_nents, mr->length);
+
 	key = (u8)(mr->rkey & 0x000000FF);
 	ib_update_fast_reg_key(mr, ++key);
-	fastreg_wr.rkey = mr->rkey;
+
+	reg_wr.wr.next = NULL;
+	reg_wr.wr.opcode = IB_WR_REG_MR;
+	reg_wr.wr.wr_id = (uintptr_t)mw;
+	reg_wr.wr.num_sge = 0;
+	reg_wr.wr.send_flags = 0;
+	reg_wr.mr = mr;
+	reg_wr.key = mr->rkey;
+	reg_wr.access = writing ?
+			IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
+			IB_ACCESS_REMOTE_READ;
 
 	DECR_CQCOUNT(&r_xprt->rx_ep);
-	rc = ib_post_send(ia->ri_id->qp, &fastreg_wr.wr, &bad_wr);
+	rc = ib_post_send(ia->ri_id->qp, &reg_wr.wr, &bad_wr);
 	if (rc)
 		goto out_senderr;
 
+	seg1->mr_dir = direction;
 	seg1->rl_mw = mw;
 	seg1->mr_rkey = mr->rkey;
-	seg1->mr_base = seg1->mr_dma + pageoff;
-	seg1->mr_nsegs = i;
-	seg1->mr_len = len;
-	return i;
+	seg1->mr_base = mr->iova;
+	seg1->mr_nsegs = frmr->sg_nents;
+	seg1->mr_len = mr->length;
+
+	return frmr->sg_nents;
 
 out_senderr:
 	dprintk("RPC:       %s: ib_post_send status %i\n", __func__, rc);
-	while (i--)
-		rpcrdma_unmap_one(device, --seg);
+	ib_dma_unmap_sg(device, frmr->sg, frmr->sg_nents, direction);
 	__frwr_queue_recovery(mw);
 	return rc;
 }
@@ -403,28 +421,29 @@ frwr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
 	struct rpcrdma_mr_seg *seg1 = seg;
 	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
 	struct rpcrdma_mw *mw = seg1->rl_mw;
+	struct rpcrdma_frmr *frmr = &mw->r.frmr;
 	struct ib_send_wr invalidate_wr, *bad_wr;
 	int rc, nsegs = seg->mr_nsegs;
 
 	dprintk("RPC:       %s: FRMR %p\n", __func__, mw);
 
 	seg1->rl_mw = NULL;
-	mw->r.frmr.fr_state = FRMR_IS_INVALID;
+	frmr->fr_state = FRMR_IS_INVALID;
 
 	memset(&invalidate_wr, 0, sizeof(invalidate_wr));
 	invalidate_wr.wr_id = (unsigned long)(void *)mw;
 	invalidate_wr.opcode = IB_WR_LOCAL_INV;
-	invalidate_wr.ex.invalidate_rkey = mw->r.frmr.fr_mr->rkey;
+	invalidate_wr.ex.invalidate_rkey = frmr->fr_mr->rkey;
 	DECR_CQCOUNT(&r_xprt->rx_ep);
 
-	while (seg1->mr_nsegs--)
-		rpcrdma_unmap_one(ia->ri_device, seg++);
 	read_lock(&ia->ri_qplock);
 	rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
 	read_unlock(&ia->ri_qplock);
 	if (rc)
 		goto out_err;
 
+	ib_dma_unmap_sg(ia->ri_device, frmr->sg, frmr->sg_nents, seg1->mr_dir);
+
 	rpcrdma_put_mw(r_xprt, mw);
 	return nsegs;
 
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index d252457ff21a..00773636d17e 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -195,7 +195,8 @@ enum rpcrdma_frmr_state {
 };
 
 struct rpcrdma_frmr {
-	struct ib_fast_reg_page_list	*fr_pgl;
+	struct scatterlist		*sg;
+	unsigned int			sg_nents;
 	struct ib_mr			*fr_mr;
 	enum rpcrdma_frmr_state		fr_state;
 	struct work_struct		fr_work;
-- 
1.8.4.3