On Wed, Apr 20, 2022 at 05:43:40AM -0700, Georgi Djakov wrote: > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > [ Upstream commit a9c38c5d267cb94871dfa2de5539c92025c855d7 ] > > dma_map_resource() uses pfn_valid() to ensure the range is not RAM. > However, pfn_valid() only checks for availability of the memory map for a > PFN but it does not ensure that the PFN is actually backed by RAM. > > As dma_map_resource() is the only method in DMA mapping APIs that has this > check, simply drop the pfn_valid() test from dma_map_resource(). > > Link: https://lore.kernel.org/all/20210824173741.GC623@xxxxxxx/ > Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> > Reviewed-by: Christoph Hellwig <hch@xxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20210930013039.11260-2-rppt@xxxxxxxxxx > Signed-off-by: Will Deacon <will@xxxxxxxxxx> > Fixes: 859a85ddf90e ("mm: remove pfn_valid_within() and CONFIG_HOLES_IN_ZONE") > Link: https://lore.kernel.org/r/Yl0IZWT2nsiYtqBT@xxxxxxxxxxxxx > Signed-off-by: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx> > --- > kernel/dma/mapping.c | 4 ---- > 1 file changed, 4 deletions(-) I took this, but I do not understand why patch 2/2 in this series is needed, as Sasha points out. Cleanups are nice, but is it necessary here? thanks, greg k-h
