[PATCH v3 1/5] lib: utils/irqchip: plic: Fix the off-by-one error in priority save/restore helpers

[Andreas Schwab]

On Dez 17 2022, Anup Patel wrote:

> On Mon, Dec 12, 2022 at 12:10 PM Samuel Holland <samuel at sholland.org> wrote:
>>
>> On 12/11/22 04:18, Bin Meng wrote:
>> > On Sun, Dec 11, 2022 at 6:08 PM Andreas Schwab <schwab at linux-m68k.org> wrote:
>> >>
>> >> On Dez 11 2022, Bin Meng wrote:
>> >>
>> >>> diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
>> >>> index 73d7788..4df9020 100644
>> >>> --- a/lib/utils/irqchip/plic.c
>> >>> +++ b/lib/utils/irqchip/plic.c
>> >>> @@ -38,13 +38,13 @@ static void plic_set_priority(const struct plic_data *plic, u32 source, u32 val)
>> >>>
>> >>>  void plic_priority_save(const struct plic_data *plic, u8 *priority)
>> >>>  {
>> >>> -     for (u32 i = 0; i < plic->num_src; i++)
>> >>> +     for (u32 i = 1; i <= plic->num_src; i++)
>> >>>               priority[i] = plic_get_priority(plic, i);
>> >>
>> >> That needs to adjust the index into the priority array.
>> >
>> > Does that help anything? It just confuses people more.
>> >
>> > I added function parameter descriptions in patch 2 to make it crystal
>> > clear, that the priority array needs to include interrupt source 0.
>>
>> To me, it is more confusing that when I ask to save the priority for N
>> sources, I need to allocate an array with >N elements. And leaving array
>> element 0 unused wastes memory.
>
> This can be a separate improvement patch.

It is a bug fix, not just an improvement.

-- 
Andreas Schwab, schwab at linux-m68k.org
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