Re: [PATCH V5 1/5] iommu/amd: Remove unnecessary locking from AMD iommu driver

2019-08-24 Thread Christoph Hellwig
Thank for the explanation Tom. It might make sense to add a condensed version of it to commit log for the next iteration. ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH V5 1/5] iommu/amd: Remove unnecessary locking from AMD iommu driver

2019-08-24 Thread Tom Murphy
>I have to admit I don't fully understand the concurrency issues here, but >neither do I understand what the mutex you removed might have helped to start >with. Each range in the page tables is protected by the IO virtual address allocator. The iommu driver allocates an IOVA range using locks

Re: [PATCH V5 1/5] iommu/amd: Remove unnecessary locking from AMD iommu driver

2019-08-20 Thread Christoph Hellwig
On Thu, Aug 15, 2019 at 12:09:39PM +0100, Tom Murphy wrote: > We can remove the mutex lock from amd_iommu_map and amd_iommu_unmap. > iommu_map doesn’t lock while mapping and so no two calls should touch > the same iova range. The AMD driver already handles the page table page > allocations without

[PATCH V5 1/5] iommu/amd: Remove unnecessary locking from AMD iommu driver

2019-08-15 Thread Tom Murphy
We can remove the mutex lock from amd_iommu_map and amd_iommu_unmap. iommu_map doesn’t lock while mapping and so no two calls should touch the same iova range. The AMD driver already handles the page table page allocations without locks so we can safely remove the locks. Signed-off-by: Tom Murphy