1 files changed, 32 insertions, 6 deletions

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index d6c821d48090..5f006d9e1472 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -84,6 +84,10 @@ enum {
 	NULL_Q_MQ		= 2,
 };
 
+static bool g_virt_boundary = false;
+module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
+MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
+
 static int g_no_sched;
 module_param_named(no_sched, g_no_sched, int, 0444);
 MODULE_PARM_DESC(no_sched, "No io scheduler");
@@ -366,6 +370,7 @@ NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
 NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
 NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
 NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
+NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
 
 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
 {
@@ -486,6 +491,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
 	&nullb_device_attr_zone_nr_conv,
 	&nullb_device_attr_zone_max_open,
 	&nullb_device_attr_zone_max_active,
+	&nullb_device_attr_virt_boundary,
 	NULL,
 };
 
@@ -539,7 +545,7 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item)
 static ssize_t memb_group_features_show(struct config_item *item, char *page)
 {
 	return snprintf(page, PAGE_SIZE,
-			"memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active,blocksize,max_sectors\n");
+			"memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv,zone_max_open,zone_max_active,blocksize,max_sectors,virt_boundary\n");
 }
 
 CONFIGFS_ATTR_RO(memb_group_, features);
@@ -605,6 +611,7 @@ static struct nullb_device *null_alloc_dev(void)
 	dev->zone_nr_conv = g_zone_nr_conv;
 	dev->zone_max_open = g_zone_max_open;
 	dev->zone_max_active = g_zone_max_active;
+	dev->virt_boundary = g_virt_boundary;
 	return dev;
 }
 
@@ -1369,10 +1376,13 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector,
 	}
 
 	if (dev->zoned)
-		cmd->error = null_process_zoned_cmd(cmd, op,
-						    sector, nr_sectors);
+		sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors);
 	else
-		cmd->error = null_process_cmd(cmd, op, sector, nr_sectors);
+		sts = null_process_cmd(cmd, op, sector, nr_sectors);
+
+	/* Do not overwrite errors (e.g. timeout errors) */
+	if (cmd->error == BLK_STS_OK)
+		cmd->error = sts;
 
 out:
 	nullb_complete_cmd(cmd);
@@ -1451,8 +1461,20 @@ static bool should_requeue_request(struct request *rq)
 
 static enum blk_eh_timer_return null_timeout_rq(struct request *rq, bool res)
 {
+	struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
+
 	pr_info("rq %p timed out\n", rq);
-	blk_mq_complete_request(rq);
+
+	/*
+	 * If the device is marked as blocking (i.e. memory backed or zoned
+	 * device), the submission path may be blocked waiting for resources
+	 * and cause real timeouts. For these real timeouts, the submission
+	 * path will complete the request using blk_mq_complete_request().
+	 * Only fake timeouts need to execute blk_mq_complete_request() here.
+	 */
+	cmd->error = BLK_STS_TIMEOUT;
+	if (cmd->fake_timeout)
+		blk_mq_complete_request(rq);
 	return BLK_EH_DONE;
 }
 
@@ -1473,6 +1495,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 	cmd->rq = bd->rq;
 	cmd->error = BLK_STS_OK;
 	cmd->nq = nq;
+	cmd->fake_timeout = should_timeout_request(bd->rq);
 
 	blk_mq_start_request(bd->rq);
 
@@ -1489,7 +1512,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 			return BLK_STS_OK;
 		}
 	}
-	if (should_timeout_request(bd->rq))
+	if (cmd->fake_timeout)
 		return BLK_STS_OK;
 
 	return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
@@ -1880,6 +1903,9 @@ static int null_add_dev(struct nullb_device *dev)
 				 BLK_DEF_MAX_SECTORS);
 	blk_queue_max_hw_sectors(nullb->q, dev->max_sectors);
 
+	if (dev->virt_boundary)
+		blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1);
+
 	null_config_discard(nullb);
 
 	sprintf(nullb->disk_name, "nullb%d", nullb->index);