On 12/10/21 1:46 PM, Andy Shevchenko wrote:

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platform_get_irq() will print a message when it fails.
No need to repeat this.

While at it, drop redundant check for 0 as platform_get_irq() spills
out a big WARN() in such case.

The reason you should be able to remove the "if (!irq)" test is that
platform_get_irq() never returns 0. At least, that is what the function kdoc
says. But looking at platform_get_irq_optional(), which is called by
platform_get_irq(), the out label is:

	WARN(ret == 0, "0 is an invalid IRQ number\n");
	return ret;

So 0 will be returned as-is. That is rather weird. That should be fixed to
return -ENXIO:

	if (WARN(ret == 0, "0 is an invalid IRQ number\n"))
		return -ENXIO;
	return ret;

   My unmerged patch (https://marc.info/?l=linux-kernel&m=163623041902285) does this
but returns -EINVAL instead.

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Otherwise, I do not think that removing the "if (!irq)" hunk is safe. no ?

   Of course it isn't...

It's unsubstantiated statement. The vIRQ 0 shouldn't be returned by any of
those API calls.

   We do _not_ know what needs to be fixed, that's the problem, and that's why the WARN()
is there...

If it is the case, go and fix them, no need to workaround
in each of the callers.

   There's a need to work around as long as IRQ0 ican be returned, otherwise we get
partly functioning or non-functioning drivers...

MBR, Sergey