nvme: Fix controller creation races with teardown flow

Calling nvme_sysfs_delete() when the controller is in the middle of
creation may cause several bugs. If the controller is in NEW state we
remove delete_controller file and don't delete the controller. The user
will not be able to use nvme disconnect command on that controller again,
although the controller may be active. Other bugs may happen if the
controller is in the middle of create_ctrl callback and
nvme_do_delete_ctrl() starts. For example, freeing I/O tagset at
nvme_do_delete_ctrl() before it was allocated at create_ctrl callback.

To fix all those races don't allow the user to delete the controller
before it was fully created.

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 8e6a3ada9d4440da6f7e5c8c0a857b89c8cef446..66fe301d9abbc0bbcfc55b47eea7710d425dd2aa 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3228,6 +3228,10 @@ static ssize_t nvme_sysfs_delete(struct device *dev,
 {
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
 
+       /* Can't delete non-created controllers */
+       if (!ctrl->created)
+               return -EBUSY;
+
        if (device_remove_file_self(dev, attr))
                nvme_delete_ctrl_sync(ctrl);
        return count;
@@ -4039,6 +4043,7 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl)
                nvme_queue_scan(ctrl);
                nvme_start_queues(ctrl);
        }
+       ctrl->created = true;
 }
 EXPORT_SYMBOL_GPL(nvme_start_ctrl);
 

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index d800b9a51c2c890524b0543b835807604ca56cea..2e04a36296d952ae3527f16e1cd34e2efc5ffd71 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -259,6 +259,7 @@ struct nvme_ctrl {
        struct nvme_command ka_cmd;
        struct work_struct fw_act_work;
        unsigned long events;
+       bool created;
 
 #ifdef CONFIG_NVME_MULTIPATH
        /* asymmetric namespace access: */