Re: [PATCH] video: arch specific page protection support for deferred io

On Thu, Jun 25, 2009 at 4:03 PM, Andrew Morton[off-list ref] wrote:

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

quoted

On Thu, Jun 25, 2009 at 11:56 AM, Andrew
Morton[off-list ref] wrote:

quoted

On Wed, 24 Jun 2009 19:54:13 +0900 Magnus Damm [off-list ref] wrote:

quoted

From: Magnus Damm <redacted>

This patch adds arch specific page protection support to deferred io.

Instead of overwriting the info->fbops->mmap pointer with the
deferred io specific mmap callback, modify fb_mmap() to include
a #ifdef wrapped call to fb_deferred_io_mmap(). __The function
fb_deferred_io_mmap() is extended to call fb_pgprotect() in the
case of non-vmalloc() frame buffers.

With this patch uncached deferred io can be used together with
the sh_mobile_lcdcfb driver. Without this patch arch specific
page protection code in fb_pgprotect() never gets invoked with
deferred io.

Signed-off-by: Magnus Damm <redacted>
---

__For proper runtime operation with uncached vmas make sure
__"[PATCH][RFC] mm: uncached vma support with writenotify"
__is applied. There are no merge order dependencies.

So this is dependent upon a patch which is in your tree, which is in
linux-next?

I tried to say that there were _no_ dependencies merge wise. =)

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?

There may also be some dependencies related to other patches posted to
linux-fbdev-devel, for instance:
[PATCH] add mutex to fbdev for fb_mmap locking (v2)
The fb_mmap() locking will conflict with this patch.

So it may make sense to group the fbdev patches together.

quoted

The code is fbmem.c is currently filled with #ifdefs today, want me
create inline versions for fb_deferred_io_open() and
fb_deferred_io_fsync() as well?

It was a minor point.  Your call.

I'd prefer to submit a patch on top of this one if possible.

Cheers,

/ magnus

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