[PATCH v3] iommu/arm-smmu-v3: Do not use GFP_KERNEL under as spinlock

[Will Deacon]

On Wed, 21 Feb 2024 20:27:02 -0400, Jason Gunthorpe wrote:
> If the SMMU is configured to use a two level CD table then
> arm_smmu_write_ctx_desc() allocates a CD table leaf internally using
> GFP_KERNEL. Due to recent changes this is being done under a spinlock to
> iterate over the device list - thus it will trigger a sleeping while
> atomic warning:
> 
>   arm_smmu_sva_set_dev_pasid()
>     mutex_lock(&sva_lock);
>     __arm_smmu_sva_bind()
>      arm_smmu_mmu_notifier_get()
>       spin_lock_irqsave()
>       arm_smmu_write_ctx_desc()
> 	arm_smmu_get_cd_ptr()
>          arm_smmu_alloc_cd_leaf_table()
> 	  dmam_alloc_coherent(GFP_KERNEL)
> 
> [...]

Thanks guys, this looks really good now.

Applied to will (for-joerg/arm-smmu/fixes), thanks!

[1/1] iommu/arm-smmu-v3: Do not use GFP_KERNEL under as spinlock
      https://git.kernel.org/will/c/b5bf7778b722

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev