[3.19.y-ckt stable] Patch "MIPS: dma-default: Fix 32-bit fall back to GFP_DMA" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu Nov 12 20:39:43 UTC 2015


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-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From afdfb2e7f8f5bbeeb9d122111458b9533e6a2a57 Mon Sep 17 00:00:00 2001
From: James Hogan <james.hogan at imgtec.com>
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 at imgtec.com>
Fixes: a2e715a86c6d ("MIPS: DMA: Fix computation of DMA flags from device's coherent_dma_mask.")
Cc: Ralf Baechle <ralf at linux-mips.org>
Cc: linux-mips at linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9610/
Signed-off-by: Ralf Baechle <ralf at linux-mips.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 af5f046..d5096a5 100644
--- a/arch/mips/mm/dma-default.c
+++ b/arch/mips/mm/dma-default.c
@@ -100,7 +100,7 @@ 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
--
1.9.1





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