NVMe: queue usage fixes in nvme-scsi

Fixes nvme queue usages in scsi-to-nvme translation code to not get
a queue more often than it is being put, and not use the queue in an
unsafe way without it being locked.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Acked-by: Vishal Verma <vishal.l.verma@linux.intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

drivers/block/nvme-scsi.c

@@ -2039,7 +2039,7 @@ static int nvme_trans_do_nvme_io(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 	int res = SNTI_TRANSLATION_SUCCESS;
 	int nvme_sc;
 	struct nvme_dev *dev = ns->dev;
-	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
+	struct nvme_queue *nvmeq;
 	u32 num_cmds;
 	struct nvme_iod *iod;
 	u64 unit_len;
@@ -2653,7 +2653,8 @@ static int nvme_trans_start_stop(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 {
 	int res = SNTI_TRANSLATION_SUCCESS;
 	int nvme_sc;
-	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
+	struct nvme_queue *nvmeq;
+	struct nvme_command c;
 	u8 immed, pcmod, pc, no_flush, start;
 
 	immed = GET_U8_FROM_CDB(cmd, START_STOP_UNIT_CDB_IMMED_OFFSET);
@@ -2675,8 +2676,14 @@ static int nvme_trans_start_stop(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 	} else {
 		if (no_flush == 0) {
 			/* Issue NVME FLUSH command prior to START STOP UNIT */
-			nvme_sc = nvme_submit_flush_data(nvmeq, ns);
+			memset(&c, 0, sizeof(c));
+			c.common.opcode = nvme_cmd_flush;
+			c.common.nsid = cpu_to_le32(ns->ns_id);
+
+			nvmeq = get_nvmeq(ns->dev);
 			put_nvmeq(nvmeq);
+			nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
+
 			res = nvme_trans_status_code(hdr, nvme_sc);
 			if (res)
 				goto out;
@@ -2698,9 +2705,17 @@ static int nvme_trans_synchronize_cache(struct nvme_ns *ns,
 {
 	int res = SNTI_TRANSLATION_SUCCESS;
 	int nvme_sc;
-	struct nvme_queue *nvmeq = get_nvmeq(ns->dev);
+	struct nvme_command c;
+	struct nvme_queue *nvmeq;
+
+	memset(&c, 0, sizeof(c));
+	c.common.opcode = nvme_cmd_flush;
+	c.common.nsid = cpu_to_le32(ns->ns_id);
+
+	nvmeq = get_nvmeq(ns->dev);
 	put_nvmeq(nvmeq);
-	nvme_sc = nvme_submit_flush_data(nvmeq, ns);
+	nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
+
 	res = nvme_trans_status_code(hdr, nvme_sc);
 	if (res)
 		goto out;