On Wed, Aug 25, 2010 at 1:18 PM, Lal <[email protected]> wrote:
> Is below code race free?
>
> void process_context_function(void)
> {
> /* interrupts enabled here */
> spin_lock(&lock);
> modify_critical_section_list();
> spin_unlock(&lock);
> }
>
> irqreturn_t a2091_intr (int irq, void *_instance)
> {
> if(spin_trylock(&lock)) {
> modify_critical_section_list();
> spin_unlock(&lock);
> }
> else {
> /* skip */
> }
>
> return IRQ_HANDLED;
> }
>
>
> More specifically, can spin_lock & spin_trylock have race?
>
> Regards
> Lal
>
>
Have u ever considered mutex? Spinlocks are fast and efficient, but
anything after the spinlock MUST NOT SLEEP, but, or risk being scheduled OUT
of being processed by the CPU. Generally, in my present understanding, any
locks inside the interrupt context should use spinlocks, and process context
should use mutex locks, and race condition always appeared whenever the one
running in process context is competing for resources with those in
interrupt context - ie, avoid having locks that is cross-used in both
context.
Sorry if I am wrong, comment welcomed :-).
--
Regards,
Peter Teoh
