On Tue, 2013-06-25 at 10:37 +0200, Bart Van Assche wrote: > On 06/24/13 19:38, James Bottomley wrote: > > On Wed, 2013-06-12 at 14:52 +0200, Bart Van Assche wrote: > >> SCSI devices are added to the shost->__devices list from inside > >> scsi_alloc_sdev(). If something goes wrong during LUN scanning, > >> e.g. a transport layer failure occurs, then __scsi_remove_device() > >> can get invoked by the LUN scanning code for a SCSI device in > >> state SDEV_CREATED_BLOCK or SDEV_BLOCKED. If this happens then > >> the SCSI device has not yet been added to sysfs (is_visible == 0). > >> Make sure that if this happens these devices are transitioned > >> into state SDEV_DEL. This avoids that __scsi_remove_device() > >> gets invoked a second time by scsi_forget_host(). > > > > The current principle is that scsi_remove_device can fail, so the > > condition you're avoiding is expected. If you want to make it always > > succeed, we have to worry about any device state racing with an > > asynchronous remove, which looks like a whole nasty can of worms. > > > > The change log makes it sound like what you actually want to enable is > > the ability to remove devices which fail probing but which are in the > > blocked state, so why not just respin with only that, which is just > > adding the blocked states to the ->SDEV_DEL state transitions? > > If what you had in mind is the patch below, I think we agree: > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index e3d6276..eaea242 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -2185,6 +2185,8 @@ scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) > case SDEV_OFFLINE: > case SDEV_TRANSPORT_OFFLINE: > case SDEV_CANCEL: > + case SDEV_BLOCK: > + case SDEV_CREATED_BLOCK: Something like this, yes. For the probe lun case, we have to be in CREATED, so any block action transitions only to CREATED_BLOCK. The BLOCK->DEL transition can only be a result of an async remove racing with bringup, can't it? Which is something I think we still want to forbid. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
