[v2,1/1] null_blk: fix error flow for shared tags during module_init

Commit Message

Max Gurtovoy July 6, 2017, 3 p.m. UTC

In case we use shared tags feature, blk_mq_alloc_tag_set might fail
during module initialization. In that case, fail the load with the
suitble error code. Also move the tagset initialization process after
defining the amount of submition queues.

Signed-off-by: Max Gurtovoy <[e-mail]>
---

Changes from v1:
- fail module loading in case of tagset initialization failure
- call blk_mq_free_tag_set in error flow

---
 drivers/block/null_blk.c |   18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

Comments

Jens Axboe July 6, 2017, 3:52 p.m. UTC | #1

On 07/06/2017 09:00 AM, Max Gurtovoy wrote:
> In case we use shared tags feature, blk_mq_alloc_tag_set might fail
> during module initialization. In that case, fail the load with the
> suitble error code. Also move the tagset initialization process after
> defining the amount of submition queues.

I've fixed some of the typos in your commit message, but this looks
good. Applied, thanks.

Patch

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 71f4422..85c24ca 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -844,9 +844,6 @@  static int __init null_init(void)
 		queue_mode = NULL_Q_MQ;
 	}
 
-	if (queue_mode == NULL_Q_MQ && shared_tags)
-		null_init_tag_set(&tag_set);
-
 	if (queue_mode == NULL_Q_MQ && use_per_node_hctx) {
 		if (submit_queues < nr_online_nodes) {
 			pr_warn("null_blk: submit_queues param is set to %u.",
@@ -858,11 +855,19 @@  static int __init null_init(void)
 	else if (!submit_queues)
 		submit_queues = 1;
 
+	if (queue_mode == NULL_Q_MQ && shared_tags) {
+		ret = null_init_tag_set(&tag_set);
+		if (ret)
+			return ret;
+	}
+
 	mutex_init(&lock);
 
 	null_major = register_blkdev(0, "nullb");
-	if (null_major < 0)
-		return null_major;
+	if (null_major < 0) {
+		ret = null_major;
+		goto err_tagset;
+	}
 
 	if (use_lightnvm) {
 		ppa_cache = kmem_cache_create("ppa_cache", 64 * sizeof(u64),
@@ -891,6 +896,9 @@  static int __init null_init(void)
 	kmem_cache_destroy(ppa_cache);
 err_ppa:
 	unregister_blkdev(null_major, "nullb");
+err_tagset:
+	if (queue_mode == NULL_Q_MQ && shared_tags)
+		blk_mq_free_tag_set(&tag_set);
 	return ret;
 }