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    Subject[PATCH 3.13.y-ckt 15/96] MIPS: dma-default: Fix 32-bit fall back to GFP_DMA
    Date
    3.13.11-ckt30 -stable review patch.  If anyone has any objections, please let me know.

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

    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: Kamal Mostafa <kamal@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 2e94185..57f60b1 100644
    --- a/arch/mips/mm/dma-default.c
    +++ b/arch/mips/mm/dma-default.c
    @@ -92,7 +92,7 @@ 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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