dma-mapping: fix off-by-one error in dma_capable()

dma_mask is, when interpreted as address, the last valid byte, and hence
comparison msut also be done using the last valid of the buffer in
question.

Also fix the open-coded instances in lib/swiotlb.c.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Becky Bruce <beckyb@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 5bc01803f8f8..437eedb5a53b 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -549,7 +549,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
                 dma_mask = hwdev->coherent_dma_mask;
 
         ret = (void *)__get_free_pages(flags, order);
-        if (ret && swiotlb_virt_to_bus(hwdev, ret) + size > dma_mask) {
+        if (ret && swiotlb_virt_to_bus(hwdev, ret) + size - 1 > dma_mask) {
                 /*
                  * The allocated memory isn't reachable by the device.
                  */
@@ -571,7 +571,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
         dev_addr = swiotlb_virt_to_bus(hwdev, ret);
 
         /* Confirm address can be DMA'd by device */
-        if (dev_addr + size > dma_mask) {
+        if (dev_addr + size - 1 > dma_mask) {
                 printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
                        (unsigned long long)dma_mask,
                        (unsigned long long)dev_addr);