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authorPaolo Galtieri <pgaltieri@mvista.com>2005-10-11 08:29:07 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-11 09:46:54 -0700
commita0c111c631e7ab4abd68920debd44259160812ef (patch)
treebfcafa019ba2fb2bf38e5a07f9f5958b7ecb697f /arch
parent1bef40032992320dd25a266fc166bfb8fa3f2f59 (diff)
[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 <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/ppc/kernel/dma-mapping.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/ppc/kernel/dma-mapping.c b/arch/ppc/kernel/dma-mapping.c
index b566d982806c..8edee806dae7 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);