1 files changed, 74 insertions, 41 deletions

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 133060431dbd..4e1c0712278e 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -23,6 +23,7 @@
 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
 static DECLARE_FAULT_ATTR(null_timeout_attr);
 static DECLARE_FAULT_ATTR(null_requeue_attr);
+static DECLARE_FAULT_ATTR(null_init_hctx_attr);
 #endif
 
 static inline u64 mb_per_tick(int mbps)
@@ -96,11 +97,21 @@ module_param_named(home_node, g_home_node, int, 0444);
 MODULE_PARM_DESC(home_node, "Home node for the device");
 
 #ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+/*
+ * For more details about fault injection, please refer to
+ * Documentation/fault-injection/fault-injection.rst.
+ */
 static char g_timeout_str[80];
 module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444);
+MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>");
 
 static char g_requeue_str[80];
 module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444);
+MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>");
+
+static char g_init_hctx_str[80];
+module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444);
+MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>");
 #endif
 
 static int g_queue_mode = NULL_Q_MQ;
@@ -276,7 +287,7 @@ nullb_device_##NAME##_store(struct config_item *item, const char *page,	\
 {									\
 	int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\
 	struct nullb_device *dev = to_nullb_device(item);		\
-	TYPE uninitialized_var(new_value);				\
+	TYPE new_value = 0;						\
 	int ret;							\
 									\
 	ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\
@@ -302,6 +313,12 @@ static int nullb_apply_submit_queues(struct nullb_device *dev,
 	if (!nullb)
 		return 0;
 
+	/*
+	 * Make sure that null_init_hctx() does not access nullb->queues[] past
+	 * the end of that array.
+	 */
+	if (submit_queues > nr_cpu_ids)
+		return -EINVAL;
 	set = nullb->tag_set;
 	blk_mq_update_nr_hw_queues(set, submit_queues);
 	return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM;
@@ -605,6 +622,7 @@ static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
 	if (tag != -1U) {
 		cmd = &nq->cmds[tag];
 		cmd->tag = tag;
+		cmd->error = BLK_STS_OK;
 		cmd->nq = nq;
 		if (nq->dev->irqmode == NULL_IRQ_TIMER) {
 			hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
@@ -1385,6 +1403,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 		cmd->timer.function = null_cmd_timer_expired;
 	}
 	cmd->rq = bd->rq;
+	cmd->error = BLK_STS_OK;
 	cmd->nq = nq;
 
 	blk_mq_start_request(bd->rq);
@@ -1408,12 +1427,6 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
 	return null_handle_cmd(cmd, sector, nr_sectors, req_op(bd->rq));
 }
 
-static const struct blk_mq_ops null_mq_ops = {
-	.queue_rq       = null_queue_rq,
-	.complete	= null_complete_rq,
-	.timeout	= null_timeout_rq,
-};
-
 static void cleanup_queue(struct nullb_queue *nq)
 {
 	kfree(nq->tag_map);
@@ -1430,9 +1443,56 @@ static void cleanup_queues(struct nullb *nullb)
 	kfree(nullb->queues);
 }
 
+static void null_exit_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
+{
+	struct nullb_queue *nq = hctx->driver_data;
+	struct nullb *nullb = nq->dev->nullb;
+
+	nullb->nr_queues--;
+}
+
+static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
+{
+	init_waitqueue_head(&nq->wait);
+	nq->queue_depth = nullb->queue_depth;
+	nq->dev = nullb->dev;
+}
+
+static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
+			  unsigned int hctx_idx)
+{
+	struct nullb *nullb = hctx->queue->queuedata;
+	struct nullb_queue *nq;
+
+#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+	if (g_init_hctx_str[0] && should_fail(&null_init_hctx_attr, 1))
+		return -EFAULT;
+#endif
+
+	nq = &nullb->queues[hctx_idx];
+	hctx->driver_data = nq;
+	null_init_queue(nullb, nq);
+	nullb->nr_queues++;
+
+	return 0;
+}
+
+static const struct blk_mq_ops null_mq_ops = {
+	.queue_rq       = null_queue_rq,
+	.complete	= null_complete_rq,
+	.timeout	= null_timeout_rq,
+	.init_hctx	= null_init_hctx,
+	.exit_hctx	= null_exit_hctx,
+};
+
 static void null_del_dev(struct nullb *nullb)
 {
-	struct nullb_device *dev = nullb->dev;
+	struct nullb_device *dev;
+
+	if (!nullb)
+		return;
+
+	dev = nullb->dev;
 
 	ida_simple_remove(&nullb_indexes, nullb->index);
 
@@ -1473,33 +1533,6 @@ static const struct block_device_operations null_ops = {
 	.report_zones	= null_report_zones,
 };
 
-static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq)
-{
-	BUG_ON(!nullb);
-	BUG_ON(!nq);
-
-	init_waitqueue_head(&nq->wait);
-	nq->queue_depth = nullb->queue_depth;
-	nq->dev = nullb->dev;
-}
-
-static void null_init_queues(struct nullb *nullb)
-{
-	struct request_queue *q = nullb->q;
-	struct blk_mq_hw_ctx *hctx;
-	struct nullb_queue *nq;
-	int i;
-
-	queue_for_each_hw_ctx(q, hctx, i) {
-		if (!hctx->nr_ctx || !hctx->tags)
-			continue;
-		nq = &nullb->queues[i];
-		hctx->driver_data = nq;
-		null_init_queue(nullb, nq);
-		nullb->nr_queues++;
-	}
-}
-
 static int setup_commands(struct nullb_queue *nq)
 {
 	struct nullb_cmd *cmd;
@@ -1526,8 +1559,7 @@ static int setup_commands(struct nullb_queue *nq)
 
 static int setup_queues(struct nullb *nullb)
 {
-	nullb->queues = kcalloc(nullb->dev->submit_queues,
-				sizeof(struct nullb_queue),
+	nullb->queues = kcalloc(nr_cpu_ids, sizeof(struct nullb_queue),
 				GFP_KERNEL);
 	if (!nullb->queues)
 		return -ENOMEM;
@@ -1669,6 +1701,8 @@ static bool null_setup_fault(void)
 		return false;
 	if (!__null_setup_fault(&null_requeue_attr, g_requeue_str))
 		return false;
+	if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str))
+		return false;
 #endif
 	return true;
 }
@@ -1712,19 +1746,17 @@ static int null_add_dev(struct nullb_device *dev)
 			goto out_cleanup_queues;
 
 		nullb->tag_set->timeout = 5 * HZ;
-		nullb->q = blk_mq_init_queue(nullb->tag_set);
+		nullb->q = blk_mq_init_queue_data(nullb->tag_set, nullb);
 		if (IS_ERR(nullb->q)) {
 			rv = -ENOMEM;
 			goto out_cleanup_tags;
 		}
-		null_init_queues(nullb);
 	} else if (dev->queue_mode == NULL_Q_BIO) {
-		nullb->q = blk_alloc_queue_node(GFP_KERNEL, dev->home_node);
+		nullb->q = blk_alloc_queue(null_queue_bio, dev->home_node);
 		if (!nullb->q) {
 			rv = -ENOMEM;
 			goto out_cleanup_queues;
 		}
-		blk_queue_make_request(nullb->q, null_queue_bio);
 		rv = init_driver_queues(nullb);
 		if (rv)
 			goto out_cleanup_blk_queue;
@@ -1788,6 +1820,7 @@ out_cleanup_queues:
 	cleanup_queues(nullb);
 out_free_nullb:
 	kfree(nullb);
+	dev->nullb = NULL;
 out:
 	return rv;
 }