[PATCH v2 09/10] xen-blkfront: add error handling support for add_disk()

Luis Chamberlain posted 10 patches 3 years, 2 months ago
[PATCH v2 09/10] xen-blkfront: add error handling support for add_disk()
Posted by Luis Chamberlain 3 years, 2 months ago
We never checked for errors on device_add_disk() as this function
returned void. Now that this is fixed, use the shiny new error
handling. The function xlvbd_alloc_gendisk() typically does the
unwinding on error on allocating the disk and creating the tag,
but since all that error handling was stuffed inside
xlvbd_alloc_gendisk() we must repeat the tag free'ing as well.

We set the info->rq to NULL to ensure blkif_free() doesn't crash
on blk_mq_stop_hw_queues() on device_add_disk() error as the queue
will be long gone by then.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/block/xen-blkfront.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 72902104f111..86440b051766 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -2385,7 +2385,13 @@ static void blkfront_connect(struct blkfront_info *info)
 	for_each_rinfo(info, rinfo, i)
 		kick_pending_request_queues(rinfo);
 
-	device_add_disk(&info->xbdev->dev, info->gd, NULL);
+	err = device_add_disk(&info->xbdev->dev, info->gd, NULL);
+	if (err) {
+		blk_cleanup_disk(info->gd);
+		blk_mq_free_tag_set(&info->tag_set);
+		info->rq = NULL;
+		goto fail;
+	}
 
 	info->is_ready = 1;
 	return;
-- 
2.30.2


Re: [PATCH v2 09/10] xen-blkfront: add error handling support for add_disk()
Posted by Juergen Gross 3 years, 2 months ago
On 28.09.21 00:00, Luis Chamberlain wrote:
> We never checked for errors on device_add_disk() as this function
> returned void. Now that this is fixed, use the shiny new error
> handling. The function xlvbd_alloc_gendisk() typically does the
> unwinding on error on allocating the disk and creating the tag,
> but since all that error handling was stuffed inside
> xlvbd_alloc_gendisk() we must repeat the tag free'ing as well.
> 
> We set the info->rq to NULL to ensure blkif_free() doesn't crash
> on blk_mq_stop_hw_queues() on device_add_disk() error as the queue
> will be long gone by then.
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen