Hi Ohad, On Tuesday 07 June 2011 13:19:05 Ohad Ben-Cohen wrote: > On Tue, Jun 7, 2011 at 12:22 PM, Laurent Pinchart wrote: > >> + BUG_ON(!IS_ALIGNED((long)omap_domain->pgtable, IOPGD_TABLE_SIZE)); > > > > Either __get_free_pages() guarantees that the allocated memory will be > > aligned on an IOPGD_TABLE_SIZE boundary, in which case the BUG_ON() is > > unnecessary, or doesn't offer such guarantee, in which case the BUG_ON() > > will oops randomly. > > Curious, does it oops randomly today ? > (i just copied this from omap_iommu_probe, where it always existed). No that I know of :-) > It is a bit ugly though, and thinking on it again, 16KB is not that > big. We can just use kmalloc here, which does ensure the alignment > (or, better yet, kzalloc, and then ditch the memset). > > > In both cases BUG_ON() should probably be avoided. > > I disagree; we must check this so user data won't be harmed (hardware > requirement), and if a memory allocation API fails to meet its > requirements - that's really bad and user data is again at stake (much > more will break, not only the iommu driver). My point is that if the allocator guarantees the alignment (not as a side effect of the implementation, but per its API) there's no need to check it again. As the alignement is required, we need an allocator that guarantees it anyway. > > This leaks omap_domain->pgtable. > > > > The free_pages() call in omap_iommu_remove() should be removed, as > > omap_iommu_probe() doesn't allocate the pages table anymore. > > thanks ! > > > You can also remove the the struct iommu::iopgd field. > > No, I can't; it's used when the device is attached to an address space > domain. Right, my bad. > > You return 0 in the bogus pte/pgd cases. Is that intentional ? > > Yes, that's probably the most (if any) reasonable value to return here > (all other iommu implementations are doing so too). -- Regards, Laurent Pinchart -- 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
