From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxg@mellanox.com (Max Gurtovoy) Date: Thu, 4 Jan 2018 17:56:14 +0200 Subject: [PATCH 2/2] nvme: Fix subsystem multiple controllers support check In-Reply-To: <1515081374-22328-1-git-send-email-maxg@mellanox.com> References: <1515081374-22328-1-git-send-email-maxg@mellanox.com> Message-ID: <1515081374-22328-2-git-send-email-maxg@mellanox.com> From: Israel Rukshin There is a problem when another module (e.g. nvmet) takes a refcount 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: ab9e00cc72fa ("nvme: track subsystems") Reviewed-by: Max Gurtovoy Signed-off-by: Israel Rukshin --- drivers/nvme/host/core.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index cb6b08e..f6dfdd3 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -2063,6 +2063,22 @@ static ssize_t nvme_subsys_show_nqn(struct device *dev, 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; @@ -2101,7 +2117,7 @@ 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); -- 1.8.3.1