From 5507eef835c9c941e69d6d96e4b43af23eeb4ac9 Mon Sep 17 00:00:00 2001 From: Joerg Roedel <joerg.roedel@amd.com> Date: Thu, 4 Sep 2008 19:01:02 +0200 Subject: [PATCH] AMD IOMMU: add branch hints to completion wait checks This patch adds branch hints to the cecks if a completion_wait is necessary. The completion_waits in the mapping paths are unlikly because they will only happen on software implementations of AMD IOMMU which don't exists today or with lazy IO/TLB flushing when the allocator wraps around the address space. With lazy IO/TLB flushing the completion_wait in the unmapping path is unlikely too. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/kernel/amd_iommu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 679f2a8e22ee5..d743aa0adccc7 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -876,7 +876,7 @@ static dma_addr_t map_single(struct device *dev, phys_addr_t paddr, if (addr == bad_dma_address) goto out; - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); out: @@ -905,7 +905,7 @@ static void unmap_single(struct device *dev, dma_addr_t dma_addr, __unmap_single(iommu, domain->priv, dma_addr, size, dir); - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); spin_unlock_irqrestore(&domain->lock, flags); @@ -968,7 +968,7 @@ static int map_sg(struct device *dev, struct scatterlist *sglist, goto unmap; } - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); out: @@ -1014,7 +1014,7 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist, s->dma_address = s->dma_length = 0; } - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); spin_unlock_irqrestore(&domain->lock, flags); @@ -1061,7 +1061,7 @@ static void *alloc_coherent(struct device *dev, size_t size, goto out; } - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); out: @@ -1093,7 +1093,7 @@ static void free_coherent(struct device *dev, size_t size, __unmap_single(iommu, domain->priv, dma_addr, size, DMA_BIDIRECTIONAL); - if (iommu->need_sync) + if (unlikely(iommu->need_sync)) iommu_completion_wait(iommu); spin_unlock_irqrestore(&domain->lock, flags); -- GitLab