On 10.12.2021 22:35, Sergei Shtylyov wrote:
[...]
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.
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...
So, have you seen this warning (being reported) related to libahci_platform?
No (as if you need to really see this while it's obvious from the code review).
If no, what we are discussing about then? The workaround is redundant and
I don't know. :-) Your arguments so far seem bogus (sorry! :-))...
It seems you haven't got them at all. The problems of platform_get_irq() et al
shouldn't be worked around in the callers.
I have clearly explained to you what I'm working around there. If that wasn't clear
enough, I don't want to continue this talk anymore. Good luck with your patch (not this
one).
Good luck with yours, not the one that touches platform_get_irq_optional() though!
Mmh, I'm not touching it any way that would break what your patch was trying to do,
unless you've re-thopught that. It also shoudn't matter whose patch gets merged 1st
other than some small adaptation).
BTW, looking at [1], this comment is wrong:
+ * Return: non-zero IRQ number on success, negative error number on failure.
It doesn't mention 0 which you return from this function.
Also, your commit log is wrong in the description of how to handle the result:
<<
Now:
ret = platform_get_irq_optional(...);
if (ret != -ENXIO)
return ret; // respect deferred probe
if (ret > 0)
...we get an IRQ...
>>
The (ret != -ENXIO) check also succeeds on the (positive) IRQ #s, so the
following code becomes unreachable. :-/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ed7027fdf4ec41ed6df6814956dc11860232a9d5
MBR, Sergey
