Re: [PATCH v5 14/14] PCI: Add debug printing to window sizing

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Low] PCI: inverted range printed for zero-sized window in
  __pbus_size_mem()
--

commit 75a33ac81964888053244c6e6481c6c66d89219a
Author: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

PCI: Add debug printing to window sizing

This commit adds a pci_dbg() print in __pbus_size_mem() to log the
calculated bridge window size, alignment, non-aligning resource counts,
gap, and partial blocks.

> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 86c9557bc2fb4..22da18347488c 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c

[ ... ]

> @@ -1379,7 +1379,28 @@ static resource_size_t __pbus_size_mem(struct pci_bus *bus,
>  	*head_align = calculate_head_align(aligns, max_order);
>  	*head_align = max(*head_align, win_align);
>  
> -	return ALIGN(max(winsize + gap, min_size), win_align);
> +	final_winsize = ALIGN(max(winsize + gap, min_size), win_align);
> +
> +	if (bus->self) {
> +		int idx = pci_resource_num(bus->self, b_res);
> +		const char *r_name = pci_resource_name(bus->self, idx);
> +		struct resource print_res = *b_res; /* b_res update is delayed */
> +
> +		resource_set_range(&print_res, *head_align, final_winsize);
> +		if (final_winsize) {
> +			print_res.flags &= ~(IORESOURCE_UNSET |
> +					     IORESOURCE_DISABLED);
> +		} else {
> +			print_res.flags |= IORESOURCE_DISABLED;
> +		}

[Severity: Low]
Should the else branch also set IORESOURCE_UNSET on print_res when
final_winsize is 0?

When final_winsize is 0, resource_set_range() sets print_res.start to
*head_align and print_res.end to *head_align - 1.  If b_res does not
already have IORESOURCE_UNSET set (for example when initialized by
pci_bridge_check_ranges() during hotplug or !preserve_config probing),
%pR formats print_res as an inverted range such as
[mem 0x00100000-0x000fffff disabled] instead of
[mem size 0x00000000 disabled].

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261106134341.39493-1-ilpo.jarvinen@linux.intel.com?part=14