Hi Hiroshi, On Thursday, August 23, 2012 8:15 AM Hiroshi Doyu wrote: > On Thu, 23 Aug 2012 07:58:34 +0200 > Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > > Hello, > > > > On Wednesday, August 22, 2012 3:37 PM Hiroshi Doyu wrote: > > > > > KyongHo Cho <pullip.cho@xxxxxxxxxxx> wrote @ Wed, 22 Aug 2012 14:47:00 +0200: > > > > > > > vzalloc() call in __iommu_alloc_buffer() also causes BUG() in atomic context. > > > > > > Right. > > > > > > I've been thinking that kzalloc() may be enough here, since > > > vzalloc() was introduced to avoid allocation failure for big chunk of > > > memory, but I think that it's unlikely that the number of page array > > > can be so big. So I propose to drop vzalloc() here, and just simply to > > > use kzalloc only as below(*1). > > > > We already had a discussion about this, so I don't think it makes much sense to > > change it back to kzalloc. This vmalloc() call won't hurt anyone. It should not > > be considered a problem for atomic allocations, because no sane driver will try > > to allocate buffers larger than a dozen KiB with GFP_ATOMIC flag. I would call > > such try a serious bug, which we should not care here. > > Ok, I've already sent v2 just now, where, instead of changing it back, > just with GFP_ATOMIC, kzalloc() would be selected, just in case. I guess > that this would be ok(a bit safer?) I've posted some comments to v2. If you agree with my suggestion, no changes around those vmalloc() calls will be needed. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>