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SubjectRe: [PATCH v2 03/10] nvme-multipath: add error handling support for add_disk()
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On 9/28/21 12:00 AM, Luis Chamberlain wrote:
> We never checked for errors on add_disk() as this function
> returned void. Now that this is fixed, use the shiny new
> error handling.
>
> Since we now can tell for sure when a disk was added, move
> setting the bit NVME_NSHEAD_DISK_LIVE only when we did
> add the disk successfully.
>
> Nothing to do here as the cleanup is done elsewhere. We take
> care and use test_and_set_bit() because it is protects against
> two nvme paths simultaneously calling device_add_disk() on the
> same namespace head.
>
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> ---
> drivers/nvme/host/multipath.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index e8ccdd398f78..35cace4f3f5f 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -496,13 +496,22 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
> static void nvme_mpath_set_live(struct nvme_ns *ns)
> {
> struct nvme_ns_head *head = ns->head;
> + int rc;
>
> if (!head->disk)
> return;
>
> + /*
> + * test_and_set_bit() is used because it is protecting against two nvme
> + * paths simultaneously calling device_add_disk() on the same namespace
> + * head.
> + */
> if (!test_and_set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
> - device_add_disk(&head->subsys->dev, head->disk,
> - nvme_ns_id_attr_groups);
> + rc = device_add_disk(&head->subsys->dev, head->disk,
> + nvme_ns_id_attr_groups);
> + if (rc)
> + return;
> + set_bit(NVME_NSHEAD_DISK_LIVE, &head->flags);
> nvme_add_ns_head_cdev(head);
> }
>
> Errm.
Setting the same bit twice?
And shouldn't you unset the bit if 'device_add_disk()' fails?

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer

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