Messages in this thread |  | | | Date | Mon, 03 Mar 2008 13:09:13 +0900 | | From | Tejun Heo <> | | Subject | Re: [PATCH] block: fix residual byte count handling | |
FUJITA Tomonori wrote:
>> - I think bugs caused by using raw_data_len instead of data_len are more
>> subtle than the other way around. Using data_len instead of
>> raw_data_len usually affects the application layer while using
>> raw_data_len instead of data_len affects the DMA engine and transport layer.
>
> If we add extra_len, we can get what raw_data_len and data_len
> provide.
>
> I can't see what changing the meaning of rq->data_len (and
> investigating all the block drivers) gives us.
No matter which way you go, you change the meaning of rq->data_len and
you MUST inspect rq->data_len usage whichever way you go. Apply your
patch and try to do sg IO on IDE cdrom w/ various transfer lengths.
--
tejun
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