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:
break;
default:
goto illegal;
--
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