This is a note to let you know that I have just added a patch titled
MIPS: dma-default: Fix 32-bit fall back to GFP_DMA
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt19.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From b82f3ac74adcd2db39ce052deb9b14d837bc7d09 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan@xxxxxxxxxx>
Date: Fri, 27 Mar 2015 08:33:43 +0000
Subject: MIPS: dma-default: Fix 32-bit fall back to GFP_DMA
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@xxxxxxxxxx>
Fixes: a2e715a86c6d ("MIPS: DMA: Fix computation of DMA flags from device's coherent_dma_mask.")
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/9610/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
arch/mips/mm/dma-default.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
index 44b6dff5aba2..a1087593b3c2 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -94,7 +94,7 @@ static gfp_t massage_gfp_flags(const struct device *dev, gfp_t gfp)
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
