Re: [RFC] Reverting "bd_mount_mutex" to "bd_mount_sem"

From: Ingo Molnar
Date: Wed Sep 27 2006 - 10:05:24 EST

* Srinivasa Ds <srinivasa@xxxxxxxxxx> wrote:

> On debugging I found out that,"dmsetup suspend <device name>" calls
> "freeze_bdev()",which locks "bd_mount_mutex" to make sure that no new
> mounts happen on bdev until thaw_bdev() is called.
> This "thaw_bdev()" is getting called when we resume the device
> through "dmsetup resume <device-name>".
> Hence we have 2 processes,one of which locks
> "bd_mount_mutex"(dmsetup suspend) and Another(dmsetup resume) unlocks
> it.

hm, to me this seems quite a fragile construct - even if the
mutex-debugging warning is worked around by reverting to a semaphore.

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