On Fri, Dec 13, 2013 at 01:19:36PM -0500, Alan Stern wrote: > On Fri, 13 Dec 2013, Sarah Sharp wrote: > > > > Given the way things work now, I suspect these warnings are truly > > > harmless. We could simply get rid of the WARN in sysfs_remove_group. > > > > > > The alternative is to call device_del for SCSI targets earlier on, such > > > as when their hosts are unregistered. I don't know how James would > > > feel about this approach. It would be difficult because targets use > > > their own reference counts instead of relying on the usual device > > > refcounting mechanism. > > > > Thanks for looking into this. I think just getting rid of the WARN > > would be sufficient. Can you make a patch for that? > > Easily. The downside is that there would no longer be any warning > when someone tries to remove a wrong subdirectory by mistake. > > > The patch still won't help with the UAS issues with > > scsi_init_shared_tag_map though. > > I wasn't clear on the reason for that problem. Does it also arise from > late device_del for scsi_target? I could try to change the way that > works, if anybody (Hans?) would like to test it. I can certainly test it with my UAS device as well. I don't know if the issue arises from the late device_del. Looking at Hans' stack trace, the BUG in blk_free_tags gets triggered when the scsi_host is released before the block_queue release. So I don't think moving the scsi_target delete sooner would help? I really don't know anything about the SCSI or block layer though. I can confirm that simply removing the BUG() call in blk_free_tags allows the partitions on the UAS device to be mounted after it was hot-removed in the middle of video playback. Hans, maybe in order to get an answer to your question[1], you should submit a patch to the block layer maintainer, Jens Axboe? Sarah Sharp [1] http://www.spinics.net/lists/linux-scsi/msg70002.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
