lkml.org 
[lkml]   [2002]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: linux-2.5.2-pre11/drivers/loop.c bio question
On Sat, Jan 12 2002, Adam J. Richter wrote:
> Has anyone out there tried to use linux-2.5.2-pre11/drivers/loop.c?
> In my hacked version of loop.c, do_bio_blockbacked is often
> called with a bio that has bio->bi_idx set to 1 rather than 0
> (and with bi->bi_vcnt == 1), so it thinks it has no transfers to do.
> When I add the kludge of doing "bio->bi_idx = 0;" at the beginning
> of the routine, then it works fine.

Must be some of your changes, end_that_request_last is the one that
increments the index and that is not called for loop requests.

> It is possible that my problem is self-inflicted because I
> am using a version that I have adopted the "initial value" patch to,
> and I also added a temporary hack to force the requests to be processed
> one sector at a time, like so:
>
> blk_queue_max_segment_size(BLK_DEFAULT_QUEUE(MAJOR_NR), 512);

Well that change has absolutely zero impact on loop, so you cannot
possibly see any changes from that. Besides, _if_ it would have an
effect you did not limit the segment size to 512 bytes -- there is no
splitting going on, so you would still receive up to 4k of data at the
time per segment.

--
Jens Axboe

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:18    [W:0.048 / U:1.332 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site