> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Wednesday, February 1, 2023 4:26 AM > > On Tue, Jan 31, 2023 at 03:06:35PM -0500, Matthew Rosato wrote: > > @@ -799,13 +794,14 @@ > EXPORT_SYMBOL_GPL(vfio_file_enforced_coherent); > > void vfio_file_set_kvm(struct file *file, struct kvm *kvm) > > { > > struct vfio_group *group = file->private_data; > > + unsigned long flags; > > > > if (!vfio_file_is_group(file)) > > return; > > > > - mutex_lock(&group->group_lock); > > + spin_lock_irqsave(&group->kvm_ref_lock, flags); > > group->kvm = kvm; > > - mutex_unlock(&group->group_lock); > > + spin_unlock_irqrestore(&group->kvm_ref_lock, flags); > > We know we are in a sleeping context here so these are just > 'spin_lock()', same with the other one a dumb question. Why spinlock is required here? 😊 Regards, Yi Liu