Commit b837b283 authored Jan 04, 2018 by Israel Rukshin Committed by Christoph Hellwig Jan 08, 2018

nvme: fix subsystem multiple controllers support check



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: ab9e00cc ("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>

parent 85088c4a

drivers/nvme/host/core.c

+17 −1

Original line number	Diff line number	Diff line
		@@ -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);