Re: [PATCH v3 2/2] MIPS: io: add a barrier after register read in readX()

[James Hogan]

On Thu, Apr 12, 2018 at 10:51:49PM +0100, James Hogan wrote:
> On Tue, Apr 03, 2018 at 08:55:04AM -0400, Sinan Kaya wrote:
> > While a barrier is present in writeX() function before the register write,
> > a similar barrier is missing in the readX() function after the register
> > read. This could allow memory accesses following readX() to observe
> > stale data.
> > 
> > Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> > Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
> 
> Both patches look like obvious improvements to me, so I'm happy to apply
> to my fixes branch.

Though having said that, a comment to go with the rmb() (as suggested by
checkpatch) to detail the situation we're concerned about would be nice
to have.

Cheers
James

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