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 <johnzzpcrys...@gmail.com> Tested-and-reported-by: Zeng Rujia <zengru...@sangfor.com.cn> 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; -- 1.8.3.1
