[Drbd-dev] [PATCH v5 05/12] block: Kill bi_destructor

[Tejun Heo]

Hello,

On Wed, Aug 08, 2012 at 05:21:54PM -0700, Kent Overstreet wrote:
> > What's wrong with good ol' NULL?
> 
> If it's NULL, we can't distinguish between bios where that field wasn't
> set (i.e. bios that were statically allocated somewhere) from bios that
> were allocated by bio_kmalloc().
> 
> It's just there to make debugging easier - if bi_cnt goes to 0 on a bio
> where it shouldn't we'll catch it at the BUG_ON() in bio_free() instead
> of kfreeing a bad pointer.

I fail to see how that improves anything.  slab will complain clearly
if it gets passed in a pointer to static area.  The benefit is
imaginery.  If there's no bioset, it's NULL.  Let's please keep things
usual.

Thanks.

-- 
tejun