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nvme: fix subsystem multiple controllers support check

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There is a problem when another module (e.g. nvmet) takes a reference on
the nvme block device and the physical nvme drive is removed.  In that
case nvme_free_ctrl() will not be called and the controller state will be
"deleting" or "dead" unless nvmet module releases the block device.
Later on, the same nvme drive probes back and nvme_init_subsystem() will
be called and fail due to duplicate subnqn (if the nvme device doesn't
support subsystem with multiple controllers). This will cause a probe
failure.  This commit changes the check of multiple controllers support
at nvme_init_subsystem() by not counting all the controllers at "dead" or
"deleting" state (this is safe because controllers at this state will
never be active again).

Fixes: ab9e00cc72 ("nvme: track subsystems")
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Israel Rukshin 2018-01-04 17:56:14 +02:00 committed by Christoph Hellwig
parent 85088c4a0f
commit b837b28394
1 changed files with 17 additions and 1 deletions
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18
drivers/nvme/host/core.c
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@ -2069,6 +2069,22 @@ static const struct attribute_group *nvme_subsys_attrs_groups[] = {
NULL,
};
static int nvme_active_ctrls(struct nvme_subsystem *subsys)
{
int count = 0;
struct nvme_ctrl *ctrl;
mutex_lock(&subsys->lock);
list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) {
if (ctrl->state != NVME_CTRL_DELETING &&
ctrl->state != NVME_CTRL_DEAD)
count++;
}
mutex_unlock(&subsys->lock);
return count;
}
static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
{
struct nvme_subsystem *subsys, *found;
@ -2107,7 +2123,7 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
* Verify that the subsystem actually supports multiple
* controllers, else bail out.
*/
if (!(id->cmic & (1 << 1))) {
if (nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
dev_err(ctrl->device,
"ignoring ctrl due to duplicate subnqn (%s).\n",
found->subnqn);