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From: Thomas Gleixner <tglx@linutronix.de>
To: Shanker Donthineni <sdonthineni@nvidia.com>,
	Marc Zyngier <maz@kernel.org>, Michael Walle <michael@walle.cc>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Hans de Goede <hdegoede@redhat.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Shanker Donthineni <sdonthineni@nvidia.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/5] genirq: Use the common function irq_expand_nr_irqs()
Date: Tue, 31 Jan 2023 10:35:23 +0100	[thread overview]
Message-ID: <87h6w711yc.ffs@tglx> (raw)
In-Reply-To: <20230130005725.3517597-5-sdonthineni@nvidia.com>

On Sun, Jan 29 2023 at 18:57, Shanker Donthineni wrote:

> Subject: genirq: Use the common function ...

  genirq: Unify irq_expand_nr_irqs()

  irq_expand_nr_irqs() is implemented as a stub function for !SPARSEIRQ
  builds. That's not necessary as the SPARSEIRQ version returns -ENOMEM
  correctly even for the !SPARSEIRQ case as the ....


But this common function is non-obvious for the !SPARSEIRQ case. It at
least needs a comment

> +static int irq_expand_nr_irqs(unsigned int nr)
> +{
> +	if (nr > MAX_SPARSE_IRQS)
> +		return -ENOMEM;
> +	nr_irqs = nr;
> +	return 0;
> +}

or preferrably something like this:

	if (!IS_ENABLED(CONFIG_SPARSEIRQ) || nr > MAX_SPARSE_IRQS)
		return -ENOMEM;

which makes it entirely clear and also allows the compiler to optimize
is down to a 'return -ENOMEM'.

Thanks,

        tglx

  reply	other threads:[~2023-01-31  9:35 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-30  0:57 [PATCH 0/5] Increase the number of IRQ descriptors for SPARSEIRQ Shanker Donthineni
2023-01-30  0:57 ` [PATCH 1/5] genirq: Use hlist for managing resend handlers Shanker Donthineni
2023-01-31  8:59   ` Thomas Gleixner
2023-01-31 16:17     ` Shanker Donthineni
2023-01-31 17:06       ` Shanker Donthineni
2023-01-30  0:57 ` [PATCH 2/5] genirq: Allocate IRQ descriptors at boot time for !SPARSEIRQ Shanker Donthineni
2023-01-31  9:16   ` Thomas Gleixner
2023-01-31 16:41     ` Shanker Donthineni
2023-02-07 10:28       ` Thomas Gleixner
2023-01-30  0:57 ` [PATCH 3/5] genirq: Introduce two helper functions Shanker Donthineni
2023-01-31  9:20   ` Thomas Gleixner
2023-01-31 16:42     ` Shanker Donthineni
2023-01-30  0:57 ` [PATCH 4/5] genirq: Use the common function irq_expand_nr_irqs() Shanker Donthineni
2023-01-31  9:35   ` Thomas Gleixner [this message]
2023-01-31 16:43     ` Shanker Donthineni
2023-02-07 10:29       ` Thomas Gleixner
2023-01-30  0:57 ` [PATCH 5/5] genirq: Use the maple tree for IRQ descriptors management Shanker Donthineni
2023-01-31  9:52   ` Thomas Gleixner
2023-01-31 16:45     ` Shanker Donthineni
2023-02-01  6:02   ` kernel test robot
2023-02-01 13:27     ` Thomas Gleixner
2023-02-06 14:24       ` Vlastimil Babka
2023-02-06 18:10         ` Thomas Gleixner
2023-02-07 10:30         ` Thomas Gleixner
2023-02-07 14:16           ` mm, slab/slub: Ensure kmem_cache_alloc_bulk() is available early Thomas Gleixner
2023-02-07 14:45             ` Vlastimil Babka
2023-02-07 14:47               ` Vlastimil Babka
2023-02-07 18:20                 ` Thomas Gleixner
2023-02-08  9:15                   ` Vlastimil Babka
2023-02-08 20:46                     ` Thomas Gleixner
2023-02-09 20:28                       ` Matthew Wilcox
2023-02-09 23:19                         ` Thomas Gleixner
2023-02-08 13:20             ` Hyeonggon Yoo

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