[PATCH 3.10 38/54] MIPS: dma-default: Fix 32-bit fall back to GFP_DMA

Greg Kroah-Hartman
2015-10-18T02:56:21Z

From: James Hogan <james.hogan@imgtec.com>

commit 53960059d56ecef67d4ddd546731623641a3d2d1 upstream.

If there is a DMA zone (usually 24bit = 16MB I believe), but no DMA32
zone, as is the case for some 32-bit kernels, then massage_gfp_flags()
will cause DMA memory allocated for devices with a 32..63-bit
coherent_dma_mask to fall back to using __GFP_DMA, even though there may
only be 32-bits of physical address available anyway.

Correct that case to compare against a mask the size of phys_addr_t
instead of always using a 64-bit mask.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Fixes: a2e715a86c6d ("MIPS: DMA: Fix computation of DMA flags from device's coherent_dma_mask.")
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9610/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/mm/dma-default.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -91,7 +91,7 @@ static gfp_t massage_gfp_flags(const str
else
#endif
#if defined(CONFIG_ZONE_DMA) && !defined(CONFIG_ZONE_DMA32)
- if (dev->coherent_dma_mask < DMA_BIT_MASK(64))
+ if (dev->coherent_dma_mask < DMA_BIT_MASK(sizeof(phys_addr_t) * 8))
dma_flag = __GFP_DMA;
else
#endif