Re: Question about rtc_lock
Jonathan Lundell (email@example.com)
Sat, 6 Oct 2001 08:24:51 -0700
At 10:40 AM -0400 2001-10-06, Thomas Hood wrote:
>On Sat, 2001-10-06 at 09:13, Alan Cox wrote:
>> > No, but what if the rtc interrupts while the lock is held in this
>> > bit of code?
>> Thats fine. It wont take the lock
>But the first line of irq_interrupt() is:
> spin_lock (&rtc_lock);
>If one has a multi-processor machine, and CPUx is going through
>the bootflag code, which takes the rtc_lock, and that CPU is
>interrupted and enters rtc_interrupt(), which tries to take the
>rtc_lock, won't it deadlock?
>If not, then I'm missing some clue about how these spinlocks work.
rtc_interrupt(), you mean.
Even if there weren't current interrupt code doing CMOS accesses, it
would seem prudent to assume that there might be eventually, the
RTC/NVRAM being a multi-purpose shared resource.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to firstname.lastname@example.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/