Re: [PATCH hyperv-next v5 08/11] Drivers: hv: vmbus: Get the IRQ number from DeviceTree

[Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>]

On 3/13/2025 11:31 AM, Dan Carpenter wrote:
> Hi Roman,

Hi Dan,

Appreciate helping with that very much!

--
Thank you,
Roman

> kernel test robot noticed the following build warnings:
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Roman-Kisel/arm64-kvm-smccc-Introduce-and-use-API-for-detectting-hypervisor-presence/20250308-060639
> base:   3a7f7785eae7cf012af128ca9e383c91e4955354
> patch link:    https://lore.kernel.org/r/20250307220304.247725-9-romank%40linux.microsoft.com
> patch subject: [PATCH hyperv-next v5 08/11] Drivers: hv: vmbus: Get the IRQ number from DeviceTree
> config: arm64-randconfig-r071-20250312 (https://download.01.org/0day-ci/archive/20250313/202503132345.uKNehsnm-lkp@xxxxxxxxx/config)
> compiler: aarch64-linux-gcc (GCC) 14.2.0
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> | Closes: https://lore.kernel.org/r/202503132345.uKNehsnm-lkp@xxxxxxxxx/
>
> smatch warnings:
> drivers/hv/vmbus_drv.c:2355 vmbus_set_irq() warn: platform_get_irq() does not return zero
>
> vim +2355 drivers/hv/vmbus_drv.c
>
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2348  static int __maybe_unused vmbus_set_irq(struct platform_device *pdev)
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2349  {
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2350  	struct irq_data *data;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2351  	int irq;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2352  	irq_hw_number_t hwirq;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2353
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2354  	irq = platform_get_irq(pdev, 0);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07 @2355  	if (irq == 0) {
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2356  		pr_err("VMBus interrupt mapping failure\n");
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2357  		return -EINVAL;
>
> You can delete this if statement.  It's dead code.  See the comment
> next to platform_get_irq().  I wrote a blog about the history of
> this:
> https://staticthinking.wordpress.com/2023/08/07/writing-a-check-for-zero-irq-error-codes/
>
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2358  	}
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2359  	if (irq < 0) {
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2360  		pr_err("VMBus interrupt data can't be read from DeviceTree, error %d\n", irq);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2361  		return irq;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2362  	}
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2363
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2364  	data = irq_get_irq_data(irq);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2365  	if (!data) {
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2366  		pr_err("No interrupt data for VMBus virq %d\n", irq);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2367  		return -ENODEV;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2368  	}
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2369  	hwirq = irqd_to_hwirq(data);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2370
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2371  	vmbus_irq = irq;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2372  	vmbus_interrupt = hwirq;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2373  	pr_debug("VMBus virq %d, hwirq %d\n", vmbus_irq, vmbus_interrupt);
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2374
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2375  	return 0;
> 2e494cbd89c51d1 Roman Kisel    2025-03-07  2376  }