Re: copy_to/from_user and a bottom half

From: Alan Cox (alan@lxorguk.ukuu.org.uk)
Date: Thu May 18 2000 - 12:40:59 EDT

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> I tried to speed up a driver and moved copy_to_user()
> from ioctl to the bottom half of interrupt handler.

You cant touch user space from a BH. You need to pin the pages down and
use the physical address if you must do this. 2.2.x has no support for that
2.3.x has the kiovec framework

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