Re: [PATCH v2 1/5] pwm: dwc: drop redundant error check

From: Andy Shevchenko
Date: Thu Feb 08 2024 - 12:09:30 EST

On Thu, Feb 08, 2024 at 08:46:44AM +0100, Uwe Kleine-König wrote:
> On Thu, Feb 08, 2024 at 12:35:25PM +0530, Raag Jadav wrote:
> > pcim_iomap_table() fails only if pcim_iomap_regions() fails. No need to
> > check for failure if the latter is already successful.
> Is this really true? pcim_iomap_table() calls devres_alloc_node() which
> might fail if the allocation fails. (Yes, I know
>, but the rule is still to check for
> errors, right?)

We do not add a dead code to the kernel, right?

> What am I missing?

Mysterious ways of the twisted PCI devres code.
Read the above commit message again :-)

For your convenience I can elaborate. pcim_iomap_table() calls _first_
devres_find() which _will_ succeed if the pcim_iomap_regions() previously
succeeded. Does it help to understand how it designed?

With Best Regards,
Andy Shevchenko