linux-kernel - Re: [PATCH v2] staging/lustre: lloop depends on BLOCK

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]

Date:	Thu, 8 Aug 2013 05:17:47 -0700
From:	Christoph Hellwig <hch@...radead.org>
To:	"Dilger, Andreas" <andreas.dilger@...el.com>
Cc:	Christoph Hellwig <hch@...radead.org>,
	Xiong Zhou <jencce.kernel@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Peng Tao <bergwolf@...il.com>, Paul Bolle <pebolle@...cali.nl>,
	Jiri Kosina <trivial@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>
Subject: Re: [PATCH v2] staging/lustre: lloop depends on BLOCK

On Wed, Aug 07, 2013 at 07:45:17AM +0000, Dilger, Andreas wrote:
> The problem still remains that the kernel loop driver eventually depends on
> a local block device for the pages/bios to be written.  The Lustre lloop
> driver bypasses the VFS and block layer to generate RPCs from the submitted
> pages to RDMA over the network without a data copy.

No, it doesn't.  It still consumes bios just like the regular loop
driver.

Besides missing all kinds of fixes from years of kernel development the
only difference is that it takes a lustre-specific shortcut into the
direct I/O code instead of going through the pagecache.

The patch series I've pointed you to does exactly that in a generic way
and thus superceeds the lloop driver fully.

In case my previous reference was a bit to vague the series starts at:

	[PATCH V8 00/33] loop: Issue O_DIRECT aio using bio_vec

please take a look and make sure to review it in case you see any
shortcomings.

--
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/