On 11/02/2016 08:41 PM, Kirti Wankhede wrote: > On 11/2/2016 5:51 PM, Jike Song wrote: >> On 11/02/2016 12:09 PM, Alexey Kardashevskiy wrote: >>> Or you could just reference and use @mm as KVM and others do. Or there is >>> anything else you need from @current than just @mm? >>> >> >> I agree. If @mm is the only thing needed, there is really no reason to >> refer to the @task :-) >> > > In vfio_lock_acct(), that is for page accounting, if mm->mmap_sem is > already held then page accounting is deferred, where task structure is > used to get mm and work is deferred only if mm exist: > mm = get_task_mm(task); > > That is where this module need task structure. Kirti, By calling get_task_mm you hold a ref on @mm and save it in iommu, whenever you want to do something like vfio_lock_acct(), use that mm (as you said, if mmap_sem not accessible then defer it to a work, but still @mm is the whole information), and put it after the usage. I still can't see any reason that the @task have to be saved. It's always the @mm all the time. Did I miss anything? -- Thanks, Jike -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
