On Fri, Jun 26, 2009 at 3:12 AM, Andrew Morton[off-list ref] wrote:

On Fri, 26 Jun 2009 02:38:06 +0900
Paul Mundt [off-list ref] wrote:

quoted

On Thu, Jun 25, 2009 at 12:03:59AM -0700, Andrew Morton wrote:

quoted

On Thu, 25 Jun 2009 15:06:24 +0900 Magnus Damm [off-list ref] wrote:

quoted

There are 3 levels of dependencies:
1: pgprot_noncached() patches from Arnd
2: mm: uncached vma support with writenotify
3: video: arch specfic page protection support for deferred io

2 depends on 1 to compile, but 3 (this one) is disconnected from 2 and
1. So this patch can be merged independently.

OIC.  I didn't like the idea of improper runtime operation ;)

Still, it's messy.  If only because various trees might be running
untested combinations of patches.  Can we get these all into the same
tree?  Paul's?

#1 is a bit tricky. cris has already merged the pgprot_noncached() patch,
which means only m32r and xtensa are outstanding, and unfortunately
neither one of those is very fast to pick up changes. OTOH, both of those
do include asm-generic/pgtable.h, so the build shouldn't break in -next
for those two if I merge #2 and #3, even if the behaviour won't be
correct for those platforms until they merge their pgprot_noncached()
patches (I think this is ok, since it's not changing any behaviour they
experience today anyways).

It would be nice to have an ack from someone for #2 before merging it,
but it's been out there long enough that people have had ample time to
raise objections.

So I'll make this the last call for acks or nacks on #2 and #3, if none
show up in the next couple of days, I'll fold them in to my tree and
they'll show up in -next starting next week.

Well my head span off ages ago.  Could someone please resend all three
patches?

<hunts around and finds #2>

I don't really understand that one.  Have we heard fro Jaya recently?

Some f_op->mmap() callbacks invoked from mmap_region() may want to use
writenotify but also modify vma->vm_page_prot to for instance mark the
vma as uncached.

Without patch #2 the vma->vm_page_prot value set by f_op->mmap() gets
overwritten if writenotify is enabled. So in the case of writenotify
the vma will never be uncached even though f_op->mmap() marks it as
such. Patch #2 makes it possible to keep the uncached setting made by
f_op->mmap() and use writenotify.

On SuperH we want to use deferred io with an uncached vma, so patch #3
makes sure our arch specific fb_pgprotect() function gets called so we
can mark the vma as uncached.

Hope this clarifies a bit.

/ magnus

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