IB/srp: Register the indirect data buffer descriptor

Bart Van Assche · dledford · commit 330179f2fa93 · 2015-08-30T18:12:38.000-04:00
Instead of always using the global rkey for the indirect data
buffer descriptor, register that descriptor with the HCA if
the kernel module parameter register_always has been set to Y.

Signed-off-by: Bart Van Assche &lt;bart.vanassche@sandisk.com&gt;
Signed-off-by: Doug Ledford &lt;dledford@redhat.com&gt;
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -1453,18 +1453,58 @@ static int srp_map_sg(struct srp_map_state *state, struct srp_rdma_ch *ch,
 	return ret;
 }
 
+/*
+ * Register the indirect data buffer descriptor with the HCA.
+ *
+ * Note: since the indirect data buffer descriptor has been allocated with
+ * kmalloc() it is guaranteed that this buffer is a physically contiguous
+ * memory buffer.
+ */
+static int srp_map_idb(struct srp_rdma_ch *ch, struct srp_request *req,
+		       void **next_mr, void **end_mr, u32 idb_len,
+		       __be32 *idb_rkey)
+{
+	struct srp_target_port *target = ch->target;
+	struct srp_device *dev = target->srp_host->srp_dev;
+	struct srp_map_state state;
+	struct srp_direct_buf idb_desc;
+	u64 idb_pages[1];
+	int ret;
+
+	memset(&state, 0, sizeof(state));
+	memset(&idb_desc, 0, sizeof(idb_desc));
+	state.gen.next = next_mr;
+	state.gen.end = end_mr;
+	state.desc = &idb_desc;
+	state.pages = idb_pages;
+	state.pages[0] = (req->indirect_dma_addr &
+			  dev->mr_page_mask);
+	state.npages = 1;
+	state.base_dma_addr = req->indirect_dma_addr;
+	state.dma_len = idb_len;
+	ret = srp_finish_mapping(&state, ch);
+	if (ret < 0)
+		goto out;
+
+	*idb_rkey = idb_desc.key;
+
+out:
+	return ret;
+}
+
 static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 			struct srp_request *req)
 {
 	struct srp_target_port *target = ch->target;
 	struct scatterlist *scat;
 	struct srp_cmd *cmd = req->cmd->buf;
-	int len, nents, count;
+	int len, nents, count, ret;
 	struct srp_device *dev;
 	struct ib_device *ibdev;
 	struct srp_map_state state;
 	struct srp_indirect_buf *indirect_hdr;
-	u32 table_len;
+	u32 idb_len, table_len;
+	__be32 idb_rkey;
 	u8 fmt;
 
 	if (!scsi_sglist(scmnd) || scmnd->sc_data_direction == DMA_NONE)
@@ -1546,6 +1586,7 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 
 	count = min(state.ndesc, target->cmd_sg_cnt);
 	table_len = state.ndesc * sizeof (struct srp_direct_buf);
+	idb_len = sizeof(struct srp_indirect_buf) + table_len;
 
 	fmt = SRP_DATA_DESC_INDIRECT;
 	len = sizeof(struct srp_cmd) + sizeof (struct srp_indirect_buf);
@@ -1554,8 +1595,18 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
 	memcpy(indirect_hdr->desc_list, req->indirect_desc,
 	       count * sizeof (struct srp_direct_buf));
 
+	if (register_always && (dev->use_fast_reg || dev->use_fmr)) {
+		ret = srp_map_idb(ch, req, state.gen.next, state.gen.end,
+				  idb_len, &idb_rkey);
+		if (ret < 0)
+			return ret;
+		req->nmdesc++;
+	} else {
+		idb_rkey = target->rkey;
+	}
+
 	indirect_hdr->table_desc.va = cpu_to_be64(req->indirect_dma_addr);
-	indirect_hdr->table_desc.key = cpu_to_be32(target->rkey);
+	indirect_hdr->table_desc.key = idb_rkey;
 	indirect_hdr->table_desc.len = cpu_to_be32(table_len);
 	indirect_hdr->len = cpu_to_be32(state.total_len);
 
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -288,6 +288,10 @@ struct srp_map_state {
 			struct srp_fr_desc **next;
 			struct srp_fr_desc **end;
 		} fr;
+		struct {
+			void		   **next;
+			void		   **end;
+		} gen;
 	};
 	struct srp_direct_buf  *desc;
 	u64		       *pages;
