linux-kernel - Re: [PATCH 05/24] ceph: ref counted buffer

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <Pine.LNX.4.64.0912051010450.15568@cobra.newdream.net>
Date:	Sat, 5 Dec 2009 10:13:00 -0800 (PST)
From:	Sage Weil <sage@...dream.net>
To:	Ingo Oeser <ioe-lkml@...eria.de>
cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 05/24] ceph: ref counted buffer

On Sat, 5 Dec 2009, Ingo Oeser wrote:

> On Friday 04 December 2009, Sage Weil wrote:
> > struct ceph_buffer is a simple ref-counted buffer.  We transparently
> > choose between kmalloc for small buffers and vmalloc for large ones.
> > 
> > This is currently used only for allocating memory for xattr data.
> 
> Could you wrap parts of this refcounting logic around kref?
> see #include <linux/kref.h> and lib/kref.c
> 
> It avoids a bug with memory areas for free and if anybody
> optimizes or changes refcounting stuff, you get all changes for free :-)

The only real difference it looks like are

	smp_mb();

in get() and

	smp_mb__after_atomic_inc();

in put.  Is that needed for all other atomic_t refcounting too?

Switched to kref, and cleaned up the (partially unused) interface.

 fs/ceph/buffer.c    |   37 ++++++++++++++++++++++++++++++++-----
 fs/ceph/buffer.h    |   30 ++++++------------------------
 fs/ceph/inode.c     |   11 +++++++----
 fs/ceph/messenger.c |    2 +-
 fs/ceph/xattr.c     |    8 +++++---
 5 files changed, 51 insertions(+), 37 deletions(-)

sage
--
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/