linux-kernel - [PATCH 0/3] ramzswap: Eliminate stale data from compressed memory (v2 resend)

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-next>] [day] [month] [year] [list]

Message-Id: <1274074364-8838-1-git-send-email-ngupta@vflare.org>
Date:	Mon, 17 May 2010 11:02:41 +0530
From:	Nitin Gupta <ngupta@...are.org>
To:	Greg KH <greg@...ah.com>
Cc:	Pekka Enberg <penberg@...helsinki.fi>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Nigel Cunningham <nigel@...onice.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Hugh Dickins <hugh.dickins@...cali.co.uk>,
	Cyp <cyp561@...il.com>, driverdev <devel@...verdev.osuosl.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/3] ramzswap: Eliminate stale data from compressed memory (v2 resend)

Resending as Greg wanted.

(tested on mainline but should apply to linux-next cleanly)


 * Changelog: v2 vs initial patches
   - directly add swap free callback to block_device_operations
     instead of using 'notifiers' for various swap events.

ramzswap driver creates RAM based block devices which can be
used (only) as swap disks. Pages swapped to these disks are
compressed and stored in memory itself.

However, these devices do not get any notification when a swap
slot is freed (swap_map[i] reaches 0). So, we cannot free memory
allocated corresponding to this swap slot. Such stale data can
quickly accumulate in (compressed) memory defeating the whole
purpose of such devices.

To overcome this problem, we now add a callback in struct
block_device_operations which is called as soon as a swap
slot is freed.

Nitin Gupta (3):
  Add flag to identify block swap devices
  Add swap slot free callback to block_device_operations
  ramzswap: Handler for swap slot free callback

 drivers/staging/ramzswap/TODO           |    5 -----
 drivers/staging/ramzswap/ramzswap_drv.c |   22 +++++++++++++---------
 include/linux/blkdev.h                  |    2 ++
 include/linux/swap.h                    |    1 +
 mm/swapfile.c                           |    5 +++++
 5 files changed, 21 insertions(+), 14 deletions(-)
 delete mode 100644 drivers/staging/ramzswap/TODO

--
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/