From: Lianbo Jiang <lijiang@xxxxxxxxxx> [ Upstream commit a8e8af35c9f4f75f981a95488c7066d31bac4bef ] Let's move out the is_kdump_kernel() check from iommu_dma_deferred_attach() to iommu_dma_init(), and use the static-key in the fast-path to minimize the impact in the normal case. Co-developed-by: Robin Murphy <robin.murphy@xxxxxxx> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> Link: https://lore.kernel.org/r/20210126115337.20068-2-lijiang@xxxxxxxxxx Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/iommu/dma-iommu.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 00fbc591a142..07e7b2f3ba27 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -51,6 +51,8 @@ struct iommu_dma_cookie { struct iommu_domain *fq_domain; }; +static DEFINE_STATIC_KEY_FALSE(iommu_deferred_attach_enabled); + void iommu_dma_free_cpu_cached_iovas(unsigned int cpu, struct iommu_domain *domain) { @@ -389,9 +391,6 @@ static int iommu_dma_deferred_attach(struct device *dev, { const struct iommu_ops *ops = domain->ops; - if (!is_kdump_kernel()) - return 0; - if (unlikely(ops->is_attach_deferred && ops->is_attach_deferred(domain, dev))) return iommu_attach_device(domain, dev); @@ -536,7 +535,8 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys, size_t iova_off = iova_offset(iovad, phys); dma_addr_t iova; - if (unlikely(iommu_dma_deferred_attach(dev, domain))) + if (static_branch_unlikely(&iommu_deferred_attach_enabled) && + iommu_dma_deferred_attach(dev, domain)) return DMA_MAPPING_ERROR; size = iova_align(iovad, size + iova_off); @@ -694,7 +694,8 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size, *dma_handle = DMA_MAPPING_ERROR; - if (unlikely(iommu_dma_deferred_attach(dev, domain))) + if (static_branch_unlikely(&iommu_deferred_attach_enabled) && + iommu_dma_deferred_attach(dev, domain)) return NULL; min_size = alloc_sizes & -alloc_sizes; @@ -977,7 +978,8 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, unsigned long mask = dma_get_seg_boundary(dev); int i; - if (unlikely(iommu_dma_deferred_attach(dev, domain))) + if (static_branch_unlikely(&iommu_deferred_attach_enabled) && + iommu_dma_deferred_attach(dev, domain)) return 0; if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) @@ -1425,6 +1427,9 @@ void iommu_dma_compose_msi_msg(struct msi_desc *desc, static int iommu_dma_init(void) { + if (is_kdump_kernel()) + static_branch_enable(&iommu_deferred_attach_enabled); + return iova_cache_get(); } arch_initcall(iommu_dma_init); -- 2.30.2
