Messages in this thread | | | Date | Fri, 30 Apr 2010 14:18:29 -0700 (Pacific Daylight Time) | From | Peter P Waskiewicz Jr <> | Subject | Re: [PATCH linux-next v3 1/2] irq: Add CPU mask affinity hint |
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On Fri, 30 Apr 2010, Thomas Gleixner wrote:
> On Fri, 30 Apr 2010, Ben Hutchings wrote: >> On Fri, 2010-04-30 at 13:23 -0700, Peter P Waskiewicz Jr wrote: >>> +int irq_register_affinity_hint(unsigned int irq, const struct cpumask *m) >>> +{ >>> + struct irq_desc *desc = irq_to_desc(irq); >>> + unsigned long flags; >>> + >>> + if (!desc) >>> + return -EINVAL; >> >> Is it possible for irq_to_desc(irq) to be NULL? This function already >> assumes that the caller 'owns' the IRQ. > > Oh come on. Driver writers get everything wrong and not checking on an > invalid irq number is better than crashing :) > >>> +static int irq_affinity_hint_proc_show(struct seq_file *m, void *v) >>> +{ >>> + struct irq_desc *desc = irq_to_desc((long)m->private); >>> + unsigned long flags; >>> + cpumask_var_t mask; >>> + int ret = -EINVAL; >> >> I don't think this should be returning -EINVAL if the affinity hint is >> missing. That means 'invalid argument', but there is nothing invalid >> about trying to read() the corresponding file. The file should simply >> be empty if there is no hint. (Actually it might be better if it didn't >> appear at all, but that would be a pain to implement.) > > I agree that -EINVAL is not really a good match. > > How about just returning CPU_MASK_ALL if desc->affinity_hint is not > set ?
That seems reasonable to me.
cheers, -PJ
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