[PATCH 3/4] drivers/misc: Add ASpeed LPC control driver

Benjamin Herrenschmidt benh at kernel.crashing.org
Fri Jan 13 03:07:33 AEDT 2017


On Thu, 2017-01-12 at 17:00 +0100, Greg KH wrote:
> > How so ? I mean, access_ok followed by __get/__put_user is still a
> > classic, what's wrong with it ?
> 
> No "normal" driver should do that, just call copy_to/from_user and be
> done with it.  That way all of the proper locking and validation checks
> like this are done correctly for you.  Why would a driver ever call the
> "raw" __get/__put_user functions?

I supposed historically it was considered faster for some things :-)

Not a huge deal, and yes it's probably cleaner, I was just wondering
what was "racy" about access_ok() that I might have missed...

Cheers,
Ben.



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