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SubjectRe: [PATCH] irqchip/gic: add WARN_ON() to facilitate backtracking
Yejune,

On 2020-12-29 07:15, Yejune Deng wrote:
> There is two function gic_of_init() and gic_of_init_child() called
> gic_of_setup(),so add WARN_ON() to facilitate backtracking.
>
> Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
> ---
> drivers/irqchip/irq-gic.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index b1d9c22..7c11705 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -1380,7 +1380,7 @@ static bool gic_check_eoimode(struct device_node
> *node, void __iomem **base)
>
> static int gic_of_setup(struct gic_chip_data *gic, struct device_node
> *node)
> {
> - if (!gic || !node)
> + if (WARN_ON(!gic || !node))
> return -EINVAL;
>
> gic->raw_dist_base = of_iomap(node, 0);

I don't immediately see what you gain with this. If you end-up here
with NULL pointers, that either because:

- you have failed to allocate the GIC private data structure:
but as it turns out, these allocations either cannot fail (gic_data[]
is static), or the dynamic allocation in gic_of_init_child() is
already
checked.

- node is NULL: both paths already check for a NULL node, so that cannot
fail either.

My conclusion is that these checks can never trigger, and we should be
able to *remove* them altogether.

Am I missing something?

M.
--
Jazz is not dead. It just smells funny...

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