One liner to fix num_cpus == 0 on SMP kernel w/ UP box
Index: linux-2.5.60/arch/ppc/kernel/smp.c
===================================================================
RCS file: /build/cvsroot/linux-2.5.60/arch/ppc/kernel/smp.c,v
retrieving revision 1.1.1.1
diff -u -r1.1.1.1 smp.c
--- linux-2.5.60/arch/ppc/kernel/smp.c 10 Feb 2003 22:14:40 -0000 1.1.1.1
+++ linux-2.5.60/arch/ppc/kernel/smp.c 14 Feb 2003 12:22:34 -0000
@@ -65,8 +65,6 @@
int start_secondary(void *);
extern int cpu_idle(void *unused);
void smp_call_function_interrupt(void);
-static int __smp_call_function(void (*func) (void *info), void *info,
- int wait, int target);
/* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
*
@@ -188,40 +186,35 @@
* in the system.
*/
-int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
- int wait)
/*
- * [SUMMARY] Run a function on all other CPUs.
- * <func> The function to run. This must be fast and non-blocking.
- * <info> An arbitrary pointer to pass to the function.
- * <nonatomic> currently unused.
- * <wait> If true, wait (atomically) until function has completed on other CPUs.
- * [RETURNS] 0 on success, else a negative status code. Does not return until
- * remote CPUs are nearly ready to execute <<func>> or are or have executed.
+ * smp_call_function_on_cpu - Runs func on all processors in the mask
+ *
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed on other CPUs.
+ * @mask: The bitmask of CPUs to call the function
+ *
+ * Returns 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute func or have executed it.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler.
*/
-{
- /* FIXME: get cpu lock with hotplug cpus, or change this to
- bitmask. --RR */
- if (num_online_cpus() <= 1)
- return 0;
- return __smp_call_function(func, info, wait, MSG_ALL_BUT_SELF);
-}
-static int __smp_call_function(void (*func) (void *info), void *info,
- int wait, int target)
+static int smp_call_function_on_cpu(void (*func) (void *info), void *info,
+ int wait, unsigned long mask)
{
struct call_data_struct data;
int ret = -1;
int timeout;
- int ncpus = 1;
+ int i, cpu, num_cpus;
- if (target == MSG_ALL_BUT_SELF)
- ncpus = num_online_cpus() - 1;
- else if (target == MSG_ALL)
- ncpus = num_online_cpus();
+ cpu = get_cpu();
+ num_cpus = hweight32(mask);
+ if (num_cpus == 0) {
+ put_cpu_no_resched();
+ return 0;
+ }
data.func = func;
data.info = info;
@@ -233,14 +226,23 @@
spin_lock(&call_lock);
call_data = &data;
/* Send a message to all other CPUs and wait for them to respond */
- smp_message_pass(target, PPC_MSG_CALL_FUNCTION, 0, 0);
+ if (mask == cpu_online_map) {
+ smp_message_pass(MSG_ALL, PPC_MSG_CALL_FUNCTION, 0, 0);
+ } else if (mask == (cpu_online_map & ~(1UL << cpu))) {
+ smp_message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION, 0, 0);
+ } else {
+ for (i = 0; i < NR_CPUS; i++) {
+ if (cpu_online(i) && ((1UL << i) & mask))
+ smp_message_pass(i, PPC_MSG_CALL_FUNCTION, 0, 0);
+ }
+ }
/* Wait for response */
timeout = 1000000;
- while (atomic_read(&data.started) != ncpus) {
+ while (atomic_read(&data.started) != num_cpus) {
if (--timeout == 0) {
printk("smp_call_function on cpu %d: other cpus not responding (%d)\n",
- smp_processor_id(), atomic_read(&data.started));
+ cpu, atomic_read(&data.started));
goto out;
}
barrier();
@@ -249,10 +251,10 @@
if (wait) {
timeout = 1000000;
- while (atomic_read(&data.finished) != ncpus) {
+ while (atomic_read(&data.finished) != num_cpus) {
if (--timeout == 0) {
printk("smp_call_function on cpu %d: other cpus not finishing (%d/%d)\n",
- smp_processor_id(), atomic_read(&data.finished), atomic_read(&data.started));
+ cpu, atomic_read(&data.finished), atomic_read(&data.started));
goto out;
}
barrier();
@@ -263,7 +265,26 @@
out:
spin_unlock(&call_lock);
+ pu_cpu_no_resched();
return ret;
+}
+
+/*
+ * [SUMMARY] Run a function on all other CPUs.
+ * <func> The function to run. This must be fast and non-blocking.
+ * <info> An arbitrary pointer to pass to the function.
+ * <retry> unused
+ * <wait> If true, wait (atomically) until function has completed on other CPUs.
+ * [RETURNS] 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute <<func>> or are or have executed.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+
+int smp_call_function(void (*func) (void *info), void *info, int retry, int wait)
+{
+ return smp_call_function_on_cpu(func, info, wait, cpu_online_map);
}
void smp_call_function_interrupt(void)
-
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This archive was generated by hypermail 2b29 : Sat Feb 15 2003 - 22:00:53 EST