On Fri, 2008-03-07 at 08:55 +0900, Tejun Heo wrote: > James Bottomley wrote: > >> It's because of the sequence of events. Currently, driver unload > >> sequence is the same as when the device is hot unplugged. libata > >> detects that the device is gone and disables it and report it to SCSI > >> layer. SCSI layer takes over and tries to kill the SCSI device and tell > >> sd to shutdown and sd issues START_STOP to shutdown which fails w/ > >> DID_BAD_TARGET because the matching ATA device is already gone. I've > >> left it that way because I'm not sure whether spinning down the drive on > >> driver unload is the correct thing to do. The message is annoying tho. > > > > Um, it's not supposed to happen that way. Your signal that a disk is > > gone is slave destroy ... and we don't call that until after the target > > has been processed. Devices are supposed to stay online (if possible) > > from slave alloc to slave destroy. > > Currently, it's like the following. > > * Explicit unplug request via sysfs or whatever: ATA device stays online > till slave_destroy finishes. That's correct > * Hot unplugging: Nothing much libata can do. ATA device is yanked out > by the user. Yes, us too ... you just have to error all commands when the device vanishes. > * Driver unload: Dealt the same way as hot unplugging. This is the problem case: driver unloading should have a scsi_remove_host() in its path. This is the trigger that sends out the flushes/stops and calls slave_destroy. scsi_remove_host() doesn't actually return until all the destroys are completed, so it makes module unloading wait until everything is properly shut down. > Making driver unload like explicit unplug request is possible but it > will mean that drives will be spun down on driver unload, which can be > annoying to developers. You have a sysfs flag to prevent that, don't you? > In addition, the code path is shared with > controller hot unplug in which case it's probably best not to issue any > new command. So, I've been reluctant to make the change. If the change > is required, I think it can be done by adding a few lines at the top of > ata_port_detach(). Jeff, what do you think? James -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
