Re: [PATCH] dmabuf: ensure unique directory name for dmabuf stats

[Christian König]

Am 10.05.22 um 14:16 schrieb Charan Teja Kalla:
> Thanks Christian for the inputs!!
>
> On 5/10/2022 5:05 PM, Christian König wrote:
> > > And what's to keep the seconds field from also being the same?
> > Well exporting two DMA-bufs with the same ino in the same nanosecond
> > should be basically impossible, but I would rather opt for using a 64bit
> > atomic in that function.
> >
> > This should be 100% UAPI compatible and even if we manage to create one
> > buffer ever ns we need ~500years to wrap around.
> I see that the inode->i_ctime->tv_sec is already defined as
> 64bit(time64_t tv_sec), hence used it. This way we don't need extra
> static atomic_t variable just to get a unique name.
>
> Just pasting excerpt from the reply posted to Greg about why this secs
> will always be a unique: with secs field added, to get the same
> inode-secs string, the uint should overflow in the same second which is
> impossible.
>
> Let me know If you still opt for atomic variable only.

I think just using a static atomic variable here would be cleaner, that 
is 100% unique.

Your approach should probably work as well, but it looks quite constructed.

Regards,
Christian.