linux-kernel - [PATCH] [mmotm] comment on swap notify locking constraints

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]

Date:	Thu, 14 Jan 2010 20:02:51 +0530
From:	Nitin Gupta <ngupta@...are.org>
To:	Hugh Dickins <hugh.dickins@...cali.co.uk>,
	Pekka Enberg <penberg@...helsinki.fi>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@...IV.linux.org.uk>,
	Christoph Hellwig <hch@...radead.org>,
	Jens Axboe <jens.axboe@...cle.com>,
	Andi Kleen <andi@...stfloor.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] [mmotm] comment on swap notify locking constraints

A block device makes swap_slot_free_notify() callback
when the last reference to a swap slot is dropped.

This callback is made under swap_lock and often with
lock for corresponding swapcache page also held. This
is a note of warning for registered callback function
which must meet these constraints.

Signed-off-by: Nitin Gupta <ngupta@...are.org>
---
 include/linux/blkdev.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 14b95a3..e3dcff6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1295,6 +1295,7 @@ struct block_device_operations {
 						unsigned long long);
 	int (*revalidate_disk) (struct gendisk *);
 	int (*getgeo)(struct block_device *, struct hd_geometry *);
+	/* this callback is with swap_lock and often page lock also held */
 	void (*swap_slot_free_notify) (struct block_device *, unsigned long);
 	struct module *owner;
 };
-- 
1.6.2.5

--
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/