IB/srp: Register the indirect data buffer descriptor

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 <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

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);
 

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;