From: Vladimir Murzin Date: Fri, 8 Aug 2014 09:31:47 +0000 (+0100) Subject: iommu/arm-smmu: remove pgtable_page_{c,d}tor() X-Git-Url: http://git.efficios.com/?p=deliverable%2Flinux.git;a=commitdiff_plain;h=93b14135cf24668b45eb57348312b627a8539bc4 iommu/arm-smmu: remove pgtable_page_{c,d}tor() If split page table lock for PTE tables is enabled (CONFIG_SPLIT_PTLOCK_CPUS <=NR_CPUS) pgtable_page_ctor() leads to non-atomic allocation for ptlock with a spinlock held, resulting in: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 466 at kernel/locking/lockdep.c:2742 lockdep_trace_alloc+0xd8/0xf4() DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)) Modules linked in: CPU: 0 PID: 466 Comm: dma0chan0-copy0 Not tainted 3.16.0-3d47efb-clean-pl330-dma_test-ve-a15-a32-slr-m c-on-3+ #55 [<80014748>] (unwind_backtrace) from [<80011640>] (show_stack+0x10/0x14) [<80011640>] (show_stack) from [<802bf864>] (dump_stack+0x80/0xb4) [<802bf864>] (dump_stack) from [<8002385c>] (warn_slowpath_common+0x64/0x88) [<8002385c>] (warn_slowpath_common) from [<80023914>] (warn_slowpath_fmt+0x30/0x40) [<80023914>] (warn_slowpath_fmt) from [<8005d818>] (lockdep_trace_alloc+0xd8/0xf4) [<8005d818>] (lockdep_trace_alloc) from [<800d3d78>] (kmem_cache_alloc+0x24/0x144) [<800d3d78>] (kmem_cache_alloc) from [<800bfae4>] (ptlock_alloc+0x18/0x2c) [<800bfae4>] (ptlock_alloc) from [<802b1ec0>] (arm_smmu_handle_mapping+0x4c0/0x690) [<802b1ec0>] (arm_smmu_handle_mapping) from [<802b0cd8>] (iommu_map+0xe0/0x148) [<802b0cd8>] (iommu_map) from [<80019098>] (arm_coherent_iommu_map_page+0x160/0x278) [<80019098>] (arm_coherent_iommu_map_page) from [<801f4d78>] (dmatest_func+0x60c/0x1098) [<801f4d78>] (dmatest_func) from [<8003f8ac>] (kthread+0xcc/0xe8) [<8003f8ac>] (kthread) from [<8000e868>] (ret_from_fork+0x14/0x2c) ---[ end trace ce0d27e6f434acf8 ]-- Split page tables lock is not used in the driver. In fact, page tables are guarded with domain lock, so remove calls to pgtable_page_{c,d}tor(). Cc: Signed-off-by: Vladimir Murzin Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 1f10ac0d4135..398802ad9d2d 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -984,7 +984,6 @@ static void arm_smmu_free_ptes(pmd_t *pmd) { pgtable_t table = pmd_pgtable(*pmd); - pgtable_page_dtor(table); __free_page(table); } @@ -1253,10 +1252,6 @@ static int arm_smmu_alloc_init_pte(struct arm_smmu_device *smmu, pmd_t *pmd, return -ENOMEM; arm_smmu_flush_pgtable(smmu, page_address(table), PAGE_SIZE); - if (!pgtable_page_ctor(table)) { - __free_page(table); - return -ENOMEM; - } pmd_populate(NULL, pmd, table); arm_smmu_flush_pgtable(smmu, pmd, sizeof(*pmd)); }