On 04/28/2017 11:43 AM, Zhou Zhengping wrote: > When a scsi_device is unpluged from scsi controller, if the > scsi_device is still be used by application layer,it won't be > released until users release it. In this case, scsi_device_remove just set > the scsi_device's state to be SDEV_DEL. But if you plug the disk > just before the old scsi_device is released, then there will be two > scsi_device structures in scsi_host->__devices. when the next unpluging > event happens,some low-level drivers will check whether the scsi_device > has been added to host (for example, the megaraid sas series controller) > by calling scsi_device_lookup(call __scsi_device_lookup) in function > megasas_aen_polling.__scsi_device_lookup will return the first scsi_device. > Because its state is SDEV_DEL, the scsi_device_lookup will return NULL finally, > making the low-level driver assume that the scsi_device has been > removed,and won't call scsi_device_remove,which will lead the > failure of hot swap. > > Signed-off-by: Zhou Zhengping <johnzzpcrystal@xxxxxxxxx> > Tested-and-reported-by: Zeng Rujia <ZengRujia@xxxxxxxxxxxxxx> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195607 > --- > drivers/scsi/scsi.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index 61c82a3..b455619 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -1262,6 +1262,8 @@ struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, > struct scsi_device *sdev; > > list_for_each_entry(sdev, &shost->__devices, siblings) { > + if (sdev->sdev_state == SDEV_DEL) > + continue; > if (sdev->channel == channel && sdev->id == id && > sdev->lun ==lun) > return sdev; > Actually this is a similar to 2aeef605aa0 ("[SCSI] Skip deleted devices in __scsi_device_lookup_by_target()") Well spotted. Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
