On (20/12/01 21:59), John Ogness wrote:
>
> +#ifdef CONFIG_PRINTK_NMI
> +#define NUM_RECURSION_CTX 2
> +#else
> +#define NUM_RECURSION_CTX 1
> +#endif
> +
> +struct printk_recursion {
> + char count[NUM_RECURSION_CTX];
> +};
> +
> +static DEFINE_PER_CPU(struct printk_recursion, percpu_printk_recursion);
> +static char printk_recursion_count[NUM_RECURSION_CTX];
> +
> +static char *get_printk_count(void)
A nit: I think get_foo() has some sort of special meaning and one would
expect that there should be put_foo() as well, and that those have
something to do with the ref counting.
> +{
> + struct printk_recursion *rec;
> + char *count;
> +
> + if (!printk_percpu_data_ready()) {
> + count = &printk_recursion_count[0];
> + } else {
> + rec = this_cpu_ptr(&percpu_printk_recursion);
> +
> + count = &rec->count[0];
> + }
> +
> +#ifdef CONFIG_PRINTK_NMI
> + if (in_nmi())
> + count++;
> +#endif
> +
> + return count;
> +}
> +
> +static bool printk_enter(unsigned long *flags)
This better explicitly state that it disables local IRQs
printk_enter_irqsave()
I'm not very certain that printk_enter/printk_exit are best names:
if (!printk_enter())
return;
Maybe it can spell out why we couldn't enter printk so the function
name can contain recursion_limit or something.
> +{
> + char *count;
> +
> + local_irq_save(*flags);
> + count = get_printk_count();
> + /* Only 1 level of recursion allowed. */
> + if (*count > 1) {
> + local_irq_restore(*flags);
> + return false;
> + }
> + (*count)++;
> +
> + return true;
> +}
> +
> +static void printk_exit(unsigned long flags)
This enables local IRQs, so
printk_exit_irqrestore()
> +{
> + char *count;
> +
> + count = get_printk_count();
> + (*count)--;
> + local_irq_restore(flags);
> +}
-ss
