[PATCH 3.16 102/357] xtensa: fix address checks in dma_{alloc,free}_coherent

From: Greg Kroah-Hartman
Date: Fri Oct 03 2014 - 17:35:16 EST


3.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Alan Douglas <adouglas@xxxxxxxxxxx>

commit 1ca49463c44c970b1ab1d71b0f268bfdf8427a7e upstream.

Virtual address is translated to the XCHAL_KSEG_CACHED region in the
dma_free_coherent, but is checked to be in the 0...XCHAL_KSEG_SIZE
range.

Change check for end of the range from 'addr >= X' to 'addr > X - 1' to
handle the case of X == 0.

Replace 'if (C) BUG();' construct with 'BUG_ON(C);'.

Signed-off-by: Alan Douglas <adouglas@xxxxxxxxxxx>
Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/xtensa/kernel/pci-dma.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -49,9 +49,8 @@ dma_alloc_coherent(struct device *dev,si

/* We currently don't support coherent memory outside KSEG */

- if (ret < XCHAL_KSEG_CACHED_VADDR
- || ret >= XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE)
- BUG();
+ BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
+ ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);


if (ret != 0) {
@@ -68,10 +67,11 @@ EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *hwdev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
- long addr=(long)vaddr+XCHAL_KSEG_CACHED_VADDR-XCHAL_KSEG_BYPASS_VADDR;
+ unsigned long addr = (unsigned long)vaddr +
+ XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;

- if (addr < 0 || addr >= XCHAL_KSEG_SIZE)
- BUG();
+ BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
+ addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);

free_pages(addr, get_order(size));
}


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