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Commit 7e870233 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[PATCH] Fix swiotlb pci_map_sg error handling 



The overflow checking condition in lib/swiotlb.c was wrong.
It would first run a NULL pointer through virt_to_phys before
testing it. Since pci_map_sg overflow is not that uncommon
and causes data corruption (including broken file systems) when not
properly detected I think it's better to fix it in 2.6.15.

This affects x86-64 and IA64.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7ca0b3bf

lib/swiotlb.c

+3 −2
Original line number Diff line number Diff line
@@ -704,8 +704,9 @@ swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems, 
		addr = SG_ENT_VIRT_ADDRESS(sg);

		dev_addr = virt_to_phys(addr);

		if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) {

			sg->dma_address = (dma_addr_t) virt_to_phys(map_single(hwdev, addr, sg->length, dir));

			if (!sg->dma_address) {

			void *map = map_single(hwdev, addr, sg->length, dir);

			sg->dma_address = virt_to_bus(map);

			if (!map) {

				/* Don't panic here, we expect map_sg users

				   to do proper error handling. */

				swiotlb_full(hwdev, sg->length, dir, 0);