On Tue, Oct 19, 2010 at 7:01 PM, Grant Likely <grant.likely@xxxxxxxxxxxx> wrote: >> + struct omap_hwspinlock *omap_hwspinlock_request(void); ... > ERR_PTR() is only appropriate when the caller actually cares about the > failure code and has different behaviour depending on the result. Agree; the hwspinlock users can surely live without an explicit error code from the _request APIs, and some extra robustness can only do good. I'll remove it. > Disabling irqs *might* be a concern as a source of RT latency. It > might be better to make the caller responsible for managing local spin > locks and irq disable/enable. This a coming from an hardware requirement, rather than a choice the user should take. If a hwspinlock is taken over a long period of time, its other user (with which we try to achieve synchronization) might be polling the OMAP interconnect for too long (trying to take the hwspinlock) and thus preventing it to be used for other transactions. To prevent such lengthy polling on the interconnect, the hwspinlock should only be used for very short period of times, with preemption and interrupts disabled. That's why we don't give users the choice whether to disable interrupts or not - it's simply not a decision they should take. Thanks, Ohad. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
