Hi Wolfram,
On Sat, 12 Sept 2026 at 21:20, Wolfram Sang
<[email protected]> wrote:
> To help debugging, offer a list of registered hwspinlocks in debugfs. It
> will also print the responsible hwspinlock_device and if the spinlock is
> currently used. It does not show if the lock is taken because of
> side-effects. Often, reading a lock means actually taking it.
>
> Signed-off-by: Wolfram Sang <[email protected]>
Thanks for your patch!
> --- a/drivers/hwspinlock/hwspinlock_core.c
> +++ b/drivers/hwspinlock/hwspinlock_core.c
> @@ -860,5 +862,70 @@ struct hwspinlock
> *devm_hwspin_lock_request_specific(struct device *dev,
> }
> EXPORT_SYMBOL_GPL(devm_hwspin_lock_request_specific);
>
> +#ifdef CONFIG_DEBUG_FS
> +static void *hwspin_lock_seq_start(struct seq_file *s, loff_t *ppos)
> +{
> + unsigned long index = *ppos;
> + struct hwspinlock *hwlock;
> +
> + rcu_read_lock();
> + hwlock = xa_find(&hwspinlocks, &index, ULONG_MAX, XA_PRESENT);
> + *ppos = index;
> +
> + return hwlock;
> +}
> +
> +static void *hwspin_lock_seq_next(struct seq_file *s, void *v, loff_t *ppos)
> +{
> + /* Increase ppos here to avoid endless loops. Don't use
> xa_find_after() */
Do you mean xa_find_after() may loop forever?
> + unsigned long index = *ppos + 1;
> + struct hwspinlock *hwlock;
> +
> + hwlock = xa_find(&hwspinlocks, &index, ULONG_MAX, XA_PRESENT);
> + *ppos = index;
> +
> + return hwlock;
> +}
> +static int hwspin_lock_seq_show(struct seq_file *s, void *v)
> +{
> + struct hwspinlock *hwlock = v;
> + bool unused = xa_get_mark(&hwspinlocks, s->index, HWSPINLOCK_UNUSED);
> +
> + seq_printf(s, "%4llu:\t%s\t%s\n", s->index, unused ? "free" : "in
> use",
For easier parsing the output, you may want to use a string without
spaces, e.g. "busy", "active", ...
> + dev_name(hwlock->bank->dev));
> + return 0;
> +}
Reviewed-by: Geert Uytterhoeven <[email protected]>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
