Re: [PATCH v7 0/6] introduce PIDFD_SELF* sentinels

[Andrew Morton]

On Thu, 30 Jan 2025 20:40:25 +0000 Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> wrote:

> If you wish to utilise a pidfd interface to refer to the current process or
> thread it is rather cumbersome, requiring something like:
> 
> 	int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD);
> 
> 	...
> 
> 	close(pidfd);
> 
> Or the equivalent call opening /proc/self. It is more convenient to use a
> sentinel value to indicate to an interface that accepts a pidfd that we
> simply wish to refer to the current process thread.
> 

The above code sequence doesn't seem at all onerous.  I'm not
understanding why it's worth altering the kernel to permit this little
shortcut?