Re: [PATCH] usb-storage: scsiglue: Changing the command result

From: Ming Lei
Date: Tue Oct 15 2013 - 20:40:24 EST


On Wed, Oct 16, 2013 at 4:22 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, 15 Oct 2013, Vishal Annapurve wrote:
>
>> Hi Alan,
>>
>> USB storage maybe just has to say that the abort occurred. By setting the
>> US_FLIDX_TIMED_OUT bit USB storage is getting signaled that the reason was
>> time out and the command is being aborted.
>
> No. By setting the US_FLIDX_TIMED_OUT bit, usb-storage indicates that
> the command was aborted. This doesn't indicate anything about the
> reason for the abort. (Maybe this bit's name wasn't chosen very well.)
>
>> Now, it's arguable whether to change the implication of US_FLIDX_TIMED_OUT
>> bit for scsi - USB storage bridge or for entire usb storage
>
> I don't understand this. What's the difference between "scsi - USB
> storage bridge" and "entire usb storage"? Aren't they the same thing?
>
>> Or maybe scsi has
>> decided to abort so it should override the result.
>
> Of course the SCSI midlayer has decided to abort. That's the only way
> this bit can get set. But usb-storage doesn't know why SCSI decided to
> abort.

usb-storage may know if it is caused by timeout via .eh_timed_out callback
if it wants to know.


Thanks,
--
Ming Lei
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