Re: [linux-pm] Is it supposed to be ok to call del_gendisk whileuserspace is frozen?

From: Alan Stern
Date: Fri May 14 2010 - 22:38:01 EST


On Fri, 14 May 2010, Nigel Cunningham wrote:

> Hi.

> > Subject: [PATCH] fs: prevent hang on suspend/resume when MMC/SD card present
> >
> > Devices can come and go bus during suspend or resume, when the
> > writeback thread is frozen, resulting in a hang. Prevent the hang
> > by thawing the writeback thread in del_gendisk().

> Why not just make it unfreezeable to start with?

If the writeback thread were unfreezable, it might wake up and try to
write dirty pages back to disks after they were already suspended.
That would not lead to good consequences...

Alan Stern

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