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* [PATCH 0/2] Putting bio_list into struct request?
@ 2009-04-19 16:12 Jeff Garzik
  2009-04-19 16:13 ` [PATCH 1/2] Update struct request to use bio_list Jeff Garzik
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Jeff Garzik @ 2009-04-19 16:12 UTC (permalink / raw)
  To: LKML; +Cc: linux-ide, linux-scsi, axboe, hch


Now that we have bio_list in include/linux/bio.h, I wanted to see what
would happen when I replaced rq->{bio,biotail} with rq->bio_list.

Personally, I think the result is more readable, and indicates to all
users that rq->bio is really a list (even if a list with one entry).
Also, it highlights some bio users in downstream drivers, and hopefully
serves to increase the amount of bio-related review in those drivers.

The first patch is a straightforward replacement, with no code or
behavior changes (any such is a bug in the patch...):

	- null/not-null tests become bio_list_empty()
	- rq->bio becomes rq->bio_list.head
	- rq->biotail becomes rq->bio_list.tail
	- in a few cases, bio_list_xxx functions are called
	  as appropriate

The second patch are fixes to what I believe are minor bugs in the
bio-list-aware block core.  Even if patch #1 is not accepted, these
fixes are likely needed regardless.  Typically the bugs are of the type
"we forgot to update rq->biotail".

But maybe some of those are on purpose.  Who knows, give it a
look... it is quite muddled which block core functions want 'bio'
as a list, or just a singleton 'bio'.  Maybe I just got confused.

If nothing else, it helps to give this area of block another look, IMO.

	Jeff





^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2009-04-19 17:45 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-04-19 16:12 [PATCH 0/2] Putting bio_list into struct request? Jeff Garzik
2009-04-19 16:13 ` [PATCH 1/2] Update struct request to use bio_list Jeff Garzik
2009-04-19 16:14 ` [PATCH 2/2] Fix bugs found during bio_list update Jeff Garzik
2009-04-19 17:44 ` [PATCH 0/2] Putting bio_list into struct request? Jens Axboe

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