[PATCH] Fix swiotlb pci_map_sg error handling (7e870233) · Commits · 戴 / test

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:

Andi Kleen <ak@suse.de> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

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);

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