Re: [PATCH 5/5] xen/arm: smmuv1: Intelligent SMR allocation

[Julien Grall <julien@xxxxxxx>]

Hi Rahul,

On 09/03/2021 18:19, Rahul Singh wrote:
> Backport 588888a7399db352d2b1a41c9d5b3bf0fd482390
> "iommu/arm-smmu: Intelligent SMR allocation" from the Linux kernel
>
> This patch fix the stream match conflict issue when two devices have the
> same stream-id.
>
> Only difference while applying this patch is to use spinlock in place of
> mutex and move iommu_group_alloc(..) function call in
> arm_smmu_add_device(..) function from the start of the function
> to the end.
As you may remember the discussion on the SMMUv3 thread, replacing a 
spinlock by a mutex has consequences. Can you explain why this is fine?
Cheers,

--
Julien Grall