Re: [PATCH RFC net-next v2 05/18] net: pse-pd: Add support for PSE device index
From: Andrew Lunn
Date: Thu Oct 31 2024 - 17:28:54 EST
On Thu, Oct 31, 2024 at 07:27:59AM +0100, Oleksij Rempel wrote:
> On Wed, Oct 30, 2024 at 05:53:07PM +0100, Kory Maincent wrote:
>
> ...
> > /**
> > * struct pse_control - a PSE control
> > @@ -440,18 +441,22 @@ int pse_controller_register(struct pse_controller_dev *pcdev)
> >
> > mutex_init(&pcdev->lock);
> > INIT_LIST_HEAD(&pcdev->pse_control_head);
> > + ret = ida_alloc_max(&pse_ida, INT_MAX, GFP_KERNEL);
>
> s/INT_MAX/U32_MAX
* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
* or %-ENOSPC if there are no free IDs.
static inline int ida_alloc_max(struct ida *ida, unsigned int max, gfp_t gfp)
We need to be careful here, at least theoretically. Assuming a 32 bit
system, and you pass it U32_MAX, how does it return values in the
range S32_MAX..U32_MAX when it also needs to be able to return
negative numbers as errors?
I think the correct value to pass is S32_MAX, because it will always
fit in a u32, and there is space left for negative values for errors.
But this is probably theoretical, no real system should have that many
controllers.
Andrew