On Wed, May 6, 2009 at 6:21 AM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > On Tue, May 05, 2009 at 02:05:17PM -0700, Andrew Morton wrote: >> On Tue, 5 May 2009 22:38:07 +0200 >> Johannes Weiner <hannes@xxxxxxxxxxx> wrote: >> > On Tue, May 05, 2009 at 12:24:42PM -0700, Andrew Morton wrote: >> > > On Mon, 4 May 2009 11:54:32 +0200 >> > > Johannes Weiner <hannes@xxxxxxxxxxx> wrote: >> > > >> > > > A generic readonly page table lookup helper to map an address space >> > > > and an address from it to a pte. >> > > >> > > umm, OK. >> > > >> > > Is there actually some point to these three patches? If so, what is it? >> > >> > Magnus needs to check for physical contiguity of a VMAs backing pages >> > to support zero-copy exportation of video data to userspace. >> > >> > This series implements follow_pfn() so he can walk the VMA backing >> > pages and ensure their PFNs are in linear order. >> > >> > [ This patch can be collapsed with 2/3, I just thought it would be >> > easier to read the diffs when having them separate. ] >> > >> > 1/3 and 2/3: factor out the page table walk from follow_phys() into >> > follow_pte(). >> > >> > 3/3: implement follow_pfn() on top of follow_pte(). >> >> So we could bundle these patches with Magnus's patchset, or we could >> consider these three patches as a cleanup or something. >> >> Given that 3/3 introduces an unused function, I'm inclined to sit tight >> and await Magnus's work. > > Yeah, I didn't see the video guys responding on Magnus' patch yet, so > let's wait for them. > > Magnus, the actual conversion of your code should be trivial, could > you respin it on top of these three patches using follow_pfn() then? So I tested the patches in -mm (1/3, 2/3, 3/3) together with the zero copy patch and everything seems fine. Feel free to add acks from me, least for patch 1/3 and 3/3 - i know too little about the generic case to say anything about 2/3. Acked-by: Magnus Damm <damm@xxxxxxxxxx> I'll send V3 of my zero copy patch in a little while. Thanks a lot for the help! Cheers, / magnus -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
