Hi John, On Wed, 2011-12-21 at 08:19 -0800, John W. Linville wrote: > On Mon, Dec 19, 2011 at 02:00:59PM -0800, Wey-Yi Guy wrote: > > From: Johannes Berg <johannes.berg@xxxxxxxxx> > > > > The ICT code erroneously uses PAGE_SIZE. The bug > > is that PAGE_SIZE isn't necessarily 4096, so on > > such platforms this code will not work correctly > > as we'll try to attempt to read an index in the > > table that the device never wrote, it always has > > 4096-byte pages. > > > > Additionally, the manual alignment code here is > > unnecessary -- Documentation/DMA-API-HOWTO.txt > > states: > > The cpu return address and the DMA bus master address are both > > guaranteed to be aligned to the smallest PAGE_SIZE order which > > is greater than or equal to the requested size. This invariant > > exists (for example) to guarantee that if you allocate a chunk > > which is smaller than or equal to 64 kilobytes, the extent of the > > buffer you receive will not cross a 64K boundary. > > > > Just use appropriate new constants and get rid of > > the alignment code. > > > > Cc: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> > > Cc: stable@xxxxxxxxxxxxxxx > > Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> > > Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@xxxxxxxxx> > > This seems like a big patch. It is a bit late in the release cycle > to rewrite all the DMA allocation code. :-) > > What platforms does this affect? Are there actual users involved? I understand the patch is bigger than the regular patch should be generated for stable kernel. Johannes can explain better, but he is on vacation. as what I understood, he work with community user who encounter issue and root cause it is PAGE SIZE cause the problem. Thanks Wey -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
