PASID is shared by all threads in a process. So the logical place to keep track of it is in the "mm". Both ARM and X86 need to use the PASID in the "mm".
Suggested-by: Christoph Hellwig <[email protected]> Signed-off-by: Fenghua Yu <[email protected]> Reviewed-by: Tony Luck <[email protected]> --- v3: - Change CONFIG_PCI_PASID to CONFIG_IOMMU_SUPPORT because non-PCI device can have PASID in ARM (Jean) v2: - This new patch moves "pasid" from x86 specific mm_context_t to generic struct mm_struct per Christopher's comment: https://lore.kernel.org/linux-iommu/[email protected]/T/#mb57110ffe1aaa24750eeea4f93b611f0d1913911 - Jean-Philippe Brucker released a virtually same patch. I still put this patch in the series for better review. The upstream kernel only needs one of the two patches eventually. https://lore.kernel.org/linux-iommu/[email protected]/ - Change CONFIG_IOASID to CONFIG_PCI_PASID (Ashok) include/linux/mm_types.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 64ede5f150dc..1ad0e54ebbba 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -538,6 +538,10 @@ struct mm_struct { atomic_long_t hugetlb_usage; #endif struct work_struct async_put_work; + +#ifdef CONFIG_IOMMU_SUPPORT + unsigned int pasid; +#endif } __randomize_layout; /* -- 2.19.1
