Re: [PATCH v2 1/2] iommu: Use mutex instead of spinlock for iommu_device_list

[Jason Gunthorpe]

On Mon, Jan 29, 2024 at 08:04:35AM +0000, Tian, Kevin wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Friday, January 26, 2024 6:54 PM
> > 
> > The iommu_device_lock spinlock was used to protect the iommu device
> > list. However, there is no requirement to access the iommu device
> > list in interrupt context. Therefore, a mutex is sufficient.
> 
> I don't think that interrupt is the reason for spinlock otherwise
> spin_lock_irqsave() should be used instead.

Right, there is no touch of this from an interrupt

I suspect it is following the the general kernel wisdom that a
spinlock is better if the critical sections are very small.

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason