From a0c111c631e7ab4abd68920debd44259160812ef Mon Sep 17 00:00:00 2001 From: Paolo Galtieri Date: Tue, 11 Oct 2005 08:29:07 -0700 Subject: [PATCH] [PATCH] ppc highmem fix I've noticed that the calculations for seg_size and nr_segs in __dma_sync_page_highmem() (arch/ppc/kernel/dma-mapping.c) are wrong. The incorrect calculations can result in either an oops or a panic when running fsck depending on the size of the partition. The problem with the seg_size calculation is that it can result in a negative number if size is offset > size. The problem with the nr_segs caculation is returns the wrong number of segments, e.g. it returns 1 when size is 200 and offset is 4095, when it should return 2 or more. Acked-by: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ppc/kernel/dma-mapping.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/ppc/kernel/dma-mapping.c b/arch/ppc/kernel/dma-mapping.c index b566d982806..8edee806dae 100644 --- a/arch/ppc/kernel/dma-mapping.c +++ b/arch/ppc/kernel/dma-mapping.c @@ -401,10 +401,10 @@ EXPORT_SYMBOL(__dma_sync); static inline void __dma_sync_page_highmem(struct page *page, unsigned long offset, size_t size, int direction) { - size_t seg_size = min((size_t)PAGE_SIZE, size) - offset; + size_t seg_size = min((size_t)(PAGE_SIZE - offset), size); size_t cur_size = seg_size; unsigned long flags, start, seg_offset = offset; - int nr_segs = PAGE_ALIGN(size + (PAGE_SIZE - offset))/PAGE_SIZE; + int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE; int seg_nr = 0; local_irq_save(flags); -- 2.41.1