From: Yu Kuai yukuai3@huawei.com
commit fcaa174a9c995cf0af3967e55644a1543ea07e36 upstream.
In order to prevent request_queue to be freed before cleaning up blktrace debugfs entries, commit db59133e9279 ("scsi: sg: fix blktrace debugfs entries leakage") use scsi_device_get(), however, scsi_device_get() will also grab scsi module reference and scsi module can't be removed.
It's reported that blktests can't unload scsi_debug after block/001:
blktests (master) # ./check block block/001 (stress device hotplugging) [failed] +++ /root/blktests/results/nodev/block/001.out.bad 2023-06-19 Running block/001 Stressing sd +modprobe: FATAL: Module scsi_debug is in use.
Fix this problem by grabbing request_queue reference directly, so that scsi host module can still be unloaded while request_queue will be pinged by sg device.
Reported-by: Chaitanya Kulkarni chaitanyak@nvidia.com Link: https://lore.kernel.org/all/1760da91-876d-fc9c-ab51-999a6f66ad50@nvidia.com/ Fixes: db59133e9279 ("scsi: sg: fix blktrace debugfs entries leakage") Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230621160111.1433521-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/scsi/sg.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1496,7 +1496,7 @@ sg_add_device(struct device *cl_dev) int error; unsigned long iflags;
- error = scsi_device_get(scsidp); + error = blk_get_queue(scsidp->request_queue); if (error) return error;
@@ -1557,7 +1557,7 @@ cdev_add_err: out: if (cdev) cdev_del(cdev); - scsi_device_put(scsidp); + blk_put_queue(scsidp->request_queue); return error; }
@@ -1574,7 +1574,7 @@ sg_device_destroy(struct kref *kref) */
blk_trace_remove(q); - scsi_device_put(sdp->device); + blk_put_queue(q);
write_lock_irqsave(&sg_index_lock, flags); idr_remove(&sg_index_idr, sdp->index);