Re: [dm-devel] [PATCH v7 3/9] block: Add bio_reset()

[Tejun Heo <tj kernel org>]

Hello, Kent.

On Tue, Aug 28, 2012 at 10:37:30AM -0700, Kent Overstreet wrote:
> Reusing bios is something that's been highly frowned upon in the past,
> but driver code keeps doing it anyways. If it's going to happen anyways,
> we should provide a generic method.
> 
> This'll help with getting rid of bi_destructor - drivers/block/pktcdvd.c
> was open coding it, by doing a bio_init() and resetting bi_destructor.

Better to explain why some bio fields are re-ordered and why that
shouldn't make things worse cacheline-wise?

> +void bio_reset(struct bio *bio)
> +{

Function comment explaining what it does and why it does what it does
with integrity / bi_css / whatnot?

> +	unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
> +
> +	if (bio_integrity(bio))
> +		bio_integrity_free(bio, bio->bi_pool);
> +
> +	bio_disassociate_task(bio);

Is this desirable?  Why?

Thanks.

-- 
tejun