Re: [PATCH] PPC: Don't sleep in flush_dcache_icache_page()

On Thu, Aug 18, 2005 at 02:56:42PM -0300, Marcelo Tosatti wrote:

Hi Roland,

On Tue, Aug 16, 2005 at 01:56:49PM -0700, Roland Dreier wrote:

quoted

flush_dcache_icache_page() will be called on an instruction page
fault.  We can't sleep in the fault handler, so use kmap_atomic()
instead of just kmap() for the Book-E case.

Signed-off-by: Roland Dreier <redacted>

Why do you need to disable interrupts during the kmap_atomic/flush_dcache_icache
operation ? 

I fail to see how an interrupt could have any reference to the data
being dealt with here (the user page).

We just took care of this offline.  The original patch is sharing
a kmap slot with another kmap_atomic user I put in before...the
sync page user.  If an interrupt came in causing the DMA API to
be used, we would have a problem.

The clean solution was to use a different kmap slot.

-Matt