Messages in this thread | | | Subject | Re: [PATCH] Introduce "used_vectors" bitmap which can be used to reserve vectors. | From | Rusty Russell <> | Date | Sat, 15 Sep 2007 12:14:09 +1000 |
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On Fri, 2007-09-14 at 09:44 +0200, Andi Kleen wrote: > On Fri, Sep 14, 2007 at 03:14:09PM +1000, Rusty Russell wrote: > > This simplifies the io_apic.c __assign_irq_vector() logic and removes > > the explicit SYSCALL_VECTOR check, and also allows for vectors to be > > reserved by other mechanisms (ie. lguest). > > Seems reasonable even as a cleanup. > > > > > int panic_on_unrecovered_nmi; > > + > > +DECLARE_BITMAP(used_vectors, NR_VECTORS); > > +EXPORT_SYMBOL_GPL(used_vectors); > > But what is the export good for? Since it's only used at boot > a module cannot do anything useful with it.
Hmm, maybe I misunderstood. I assumed that create_irq() was also called later to get irqs for any devices which appeared later. Although I can at least check it's not in use.
The current lguest patch uses it like so (syscall_vector is a module parameter):
int init_interrupts(void) { /* If they want some strange system call vector, reserve it now */ if (syscall_vector != SYSCALL_VECTOR && test_and_set_bit(syscall_vector, used_vectors)) { printk("lg: couldn't reserve syscall %u\n", syscall_vector); return -EBUSY; } return 0; }
Thanks, Rusty.
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