From 55c25c2f14496badefd780a9f179442756216b67 Mon Sep 17 00:00:00 2001 From: Jayachandran C Date: Wed, 25 Sep 2013 18:31:05 +0530 Subject: [PATCH] MIPS: mm: Move some checks out of 'for' loop in DMA operations The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device() can be moved outside the for loop. As a side effect, this also avoids a GCC bug that caused kernel compile to fail with the error: arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu': arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852 This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version 4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize current_cpu_type() for better code." Signed-off-by: Jayachandran C Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5907/ Reviewed-by: Markos Chandras Tested-by: Markos Chandras Signed-off-by: Ralf Baechle --- arch/mips/mm/dma-default.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c index f25a7e9f8cbc..5f8b95512580 100644 --- a/arch/mips/mm/dma-default.c +++ b/arch/mips/mm/dma-default.c @@ -308,12 +308,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev, { int i; - /* Make sure that gcc doesn't leave the empty loop body. */ - for (i = 0; i < nelems; i++, sg++) { - if (cpu_needs_post_dma_flush(dev)) + if (cpu_needs_post_dma_flush(dev)) + for (i = 0; i < nelems; i++, sg++) __dma_sync(sg_page(sg), sg->offset, sg->length, direction); - } } static void mips_dma_sync_sg_for_device(struct device *dev, @@ -321,12 +319,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev, { int i; - /* Make sure that gcc doesn't leave the empty loop body. */ - for (i = 0; i < nelems; i++, sg++) { - if (!plat_device_is_coherent(dev)) + if (!plat_device_is_coherent(dev)) + for (i = 0; i < nelems; i++, sg++) __dma_sync(sg_page(sg), sg->offset, sg->length, direction); - } } int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) -- 2.34.1