- struct smp_call_struct data;
- unsigned long timeout;
- int num_cpus_to_call;
-
- /* Can deadlock when called with interrupts disabled */
- WARN_ON(irqs_disabled());
-
- data.func = func;
- data.info = info;
- data.wait = wait;
-
- cpu_clear(smp_processor_id(), to_whom);
- num_cpus_to_call = cpus_weight(to_whom);
-
- atomic_set(&data.unstarted_count, num_cpus_to_call);
- atomic_set(&data.unfinished_count, num_cpus_to_call);
-
- /* Acquire the smp_call_function_data mutex. */
- if (pointer_lock(&smp_call_function_data, &data, retry))
- return -EBUSY;
-
- /* Send a message to the requested CPUs. */
- send_ipi_message(to_whom, IPI_CALL_FUNC);
-
- /* Wait for a minimal response. */
- timeout = jiffies + HZ;
- while (atomic_read (&data.unstarted_count) > 0
- && time_before (jiffies, timeout))
- barrier();
-
- /* If there's no response yet, log a message but allow a longer
- * timeout period -- if we get a response this time, log
- * a message saying when we got it..
- */
- if (atomic_read(&data.unstarted_count) > 0) {
- long start_time = jiffies;
- printk(KERN_ERR "%s: initial timeout -- trying long wait\n",
- __func__);
- timeout = jiffies + 30 * HZ;
- while (atomic_read(&data.unstarted_count) > 0
- && time_before(jiffies, timeout))
- barrier();
- if (atomic_read(&data.unstarted_count) <= 0) {
- long delta = jiffies - start_time;
- printk(KERN_ERR
- "%s: response %ld.%ld seconds into long wait\n",
- __func__, delta / HZ,
- (100 * (delta - ((delta / HZ) * HZ))) / HZ);
- }
- }
-
- /* We either got one or timed out -- clear the lock. */
- mb();
- smp_call_function_data = NULL;
-
- /*
- * If after both the initial and long timeout periods we still don't
- * have a response, something is very wrong...
- */
- BUG_ON(atomic_read (&data.unstarted_count) > 0);
-
- /* Wait for a complete response, if needed. */
- if (wait) {
- while (atomic_read (&data.unfinished_count) > 0)
- barrier();
- }
-
- return 0;