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scsi/sg: don't grab scsi host module reference 

In order to prevent request_queue to be freed before cleaning up
blktrace debugfs entries, commit db59133e92 ("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: db59133e92 ("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>
This commit is contained in:
Yu Kuai 2023-06-22 00:01:11 +08:00 committed by Jens Axboe
parent a42fb5a75c
commit fcaa174a9c
1 changed files with 3 additions and 3 deletions
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6
drivers/scsi/sg.c
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@ -1497,7 +1497,7 @@ 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;
@ -1558,7 +1558,7 @@ cdev_add_err:
out:
if (cdev)
cdev_del(cdev);
scsi_device_put(scsidp);
blk_put_queue(scsidp->request_queue);
return error;
}
@ -1575,7 +1575,7 @@ 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);