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 <h...@infradeed.org> Signed-off-by: Fenghua Yu <fenghua...@intel.com> Reviewed-by: Tony Luck <tony.l...@intel.com> --- 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/20200414170252.714402-1-jean-phili...@linaro.org/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/20200519175502.2504091-2-jean-phili...@linaro.org/ - 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..5778db3aa42d 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_PCI_PASID + unsigned int pasid; +#endif } __randomize_layout; /* -- 2.19.1
