From: Will Deacon Date: Tue, 2 Jul 2019 15:43:24 +0000 (+0100) Subject: iommu/io-pgtable-arm: Remove redundant call to io_pgtable_tlb_sync() X-Git-Tag: v5.4-rc1~193^2^10~16^2~11 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f71da46719460acd5afa411e52dc8cdf1cb9b0ce;p=thirdparty%2Flinux.git iommu/io-pgtable-arm: Remove redundant call to io_pgtable_tlb_sync() Commit b6b65ca20bc9 ("iommu/io-pgtable-arm: Add support for non-strict mode") added an unconditional call to io_pgtable_tlb_sync() immediately after the case where we replace a block entry with a table entry during an unmap() call. This is redundant, since the IOMMU API will call iommu_tlb_sync() on this path and the patch in question mentions this: | To save having to reason about it too much, make sure the invalidation | in arm_lpae_split_blk_unmap() just performs its own unconditional sync | to minimise the window in which we're technically violating the break- | before-make requirement on a live mapping. This might work out redundant | with an outer-level sync for strict unmaps, but we'll never be splitting | blocks on a DMA fastpath anyway. However, this sync gets in the way of deferred TLB invalidation for leaf entries and is at best a questionable, unproven hack. Remove it. Signed-off-by: Will Deacon --- diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c index 0fc8dfab2abf5..a62733c6a632f 100644 --- a/drivers/iommu/io-pgtable-arm-v7s.c +++ b/drivers/iommu/io-pgtable-arm-v7s.c @@ -587,7 +587,6 @@ static size_t arm_v7s_split_blk_unmap(struct arm_v7s_io_pgtable *data, } io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true); - io_pgtable_tlb_sync(&data->iop); return size; } diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 161a7d56264d0..0d6633921c1ec 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -583,7 +583,6 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data, tablep = iopte_deref(pte, data); } else if (unmap_idx >= 0) { io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true); - io_pgtable_tlb_sync(&data->iop); return size; }