Re: [RFC PATCH v9 3/4] drm/virtio: implement userptr resource support

["Huang, Honglei" <honghuan@amd.com>]

On 10/10/2026 2:46 AM, Dmitry Osipenko wrote:
> 09.10.2026 21:38, Dmitry Osipenko пишет:
>> 24.09.2026 12:55, Honglei Huang пишет:
>>> +	mm = current->mm;
>>> +	mmgrab(mm);
>>> +	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
>>> +	new_pinned = atomic64_add_return(userptr->npages, &mm->pinned_vm);
>>> +	if (new_pinned < 0 ||
>>> +	    (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) {
>>> +		atomic64_sub(userptr->npages, &mm->pinned_vm)
>>
>> At a quick glance over other kernel code touching pinned_vm, nobody else
>> check for new_pinned < 0 and then doing atomic64_sub() for the negative
>> value will be incorrect.
> Though no, negative will restore pinned_vm. Still neg looks confusing
> and shouldn't be needed as such overflow shouldn't be possible.
> 


Got it will remove this check in next version

Regards,
Honglei