linux-kernel - Re: [dm-devel] [PATCH v2 01/26] block: Convert integrity to bvec_alloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120917210858.GC14492@google.com>
Date:	Mon, 17 Sep 2012 14:08:58 -0700
From:	Kent Overstreet <koverstreet@...gle.com>
To:	"Martin K. Petersen" <martin.petersen@...cle.com>
Cc:	Vivek Goyal <vgoyal@...hat.com>, linux-bcache@...r.kernel.org,
	linux-kernel@...r.kernel.org, dm-devel@...hat.com, axboe@...nel.dk,
	tj@...nel.org
Subject: Re: [dm-devel] [PATCH v2 01/26] block: Convert integrity to
 bvec_alloc_bs(), and a bugfix

On Wed, Sep 12, 2012 at 03:39:18PM -0400, Martin K. Petersen wrote:
> >>>>> "Kent" == Kent Overstreet <koverstreet@...gle.com> writes:
> 
> Kent,
> 
> Kent> To fix the bug first, I'd have to reorder struct bio_pair and then
> Kent> just delete two lines of code from bio_integrity_split(). But the
> Kent> reordering is unnecessary with the refactoring.
> 
> Well, a bug is a bug and the fix needs to go into stable. So we will
> need a patch that does not depend on your changes.

Alright, good point.

> I don't have a problem with adding a pointer so clones can point to the
> parent's vector. But embedding the vector into the bip was a feature.
> If you check the git log you'll see that originally I did use separate
> vector allocations.

Looks like that was 7878cba9f0037f5599004b03a1260b32d9050360 - If I
follow your commit message your primary goal was to back the bip vecs by
a per bio set mempool?

I didn't break that (excepting the issue Vivek noted) - but it is true
that my patch adds another allocation (when nr_vecs > BIP_INLINE_VECS,
anyways).

I don't know how big of a deal you think that extra allocation is. If
you're against it, this patch isn't really necessary for the immutable
bvecs I'm working on - just need it if we want integrity bvecs to be
shared like regular bvecs will be.

Something else I noticed is bio_integrity_add_page() doesn't merge bvecs
when possible, like the regular bio_add_page(). If changing it to merge
bvecs wouldn't break anything, then probably most integrity bvecs would
be under BIP_INLINE_VECS.

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