Commit f1d0b063 authored Dec 02, 2008 by Kay Sievers Committed by Linus Torvalds Dec 02, 2008

bdi: register sysfs bdi device only once per queue



Devices which share the same queue, like floppies and mtd devices, get
registered multiple times in the bdi interface, but bdi accounts only the
last registered device of the devices sharing one queue.

On remove, all earlier registered devices leak, stay around in sysfs, and
cause "duplicate filename" errors if the devices are re-created.

This prevents the creation of multiple bdi interfaces per queue, and the
bdi device will carry the dev_t name of the block device which is the
first one registered, of the pool of devices using the same queue.

[akpm@linux-foundation.org: add a WARN_ON so we know which drivers are misbehaving]
Tested-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 1b79cd04

mm/backing-dev.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -176,6 +176,9 @@ int bdi_register(struct backing_dev_info bdi, struct device parent,
		int ret = 0;
		struct device *dev;

		if (WARN_ON(bdi->dev))
		goto exit;

		va_start(args, fmt);
		dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
		va_end(args);

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