[PATCH 02/13] nvme-multipath: add error handling support for add_disk()

Luis Chamberlain
2021-10-16T00:20:12Z

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 | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index e8ccdd398f78..022837f7be41 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -496,13 +496,23 @@ 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) {
+ clear_bit(NVME_NSHEAD_DISK_LIVE, &ns->flags);
+ return;
+ }
nvme_add_ns_head_cdev(head);
}

--
2.30.2