On Fri, Jun 12, 2020 at 07:42:12PM -0700, Bart Van Assche wrote: > On 2020-06-08 10:01, Luis Chamberlain wrote: > > + /* > > + * Blktrace needs a debugfs name even for queues that don't register > > + * a gendisk, so it lazily registers the debugfs directory. But that > > + * can get us into a situation where a SCSI device is found, with no > > + * driver for it (yet). Then blktrace is used on the device, creating > > + * the debugfs directory, and only after that a driver is loaded. In > > + * that case we might already have a debugfs directory registered here. > > + * Even worse we could be racing with blktrace to register it. > > + */ > > There are LLD and ULD drivers in the SCSI subsystem. Please mention the > driver type explicitly. I assume that you are referring to SCSI ULDs > since only SCSI ULD drivers call device_add_disk()?
I've simplified this and so this is no longer a valid comment. > > case BLKTRACESETUP: > > + if (!sdp->device->request_queue->sg_debugfs_dir) > > + blk_sg_debugfs_init(sdp->device->request_queue, > > + sdp->disk->disk_name); > > How about moving the sg_debugfs_dir check into blk_sg_debugfs_init()? I found a way to not have to do any of this, the fix will be short and sweet now. Luis
