From: Kevin Corry Date: Tue, 31 Jul 2007 20:19:46 +0000 (+1000) Subject: [POWERPC] Fix num_cpus calculation in smp_call_function_map() X-Git-Tag: v2.6.23-rc2~1^2~4 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=17aa3a82aa2173a22405f862c4444656f0494a3f;p=linux-2.6 [POWERPC] Fix num_cpus calculation in smp_call_function_map() In smp_call_function_map(), num_cpus is set to the number of online CPUs minus one. However, if the CPU mask does not include all CPUs (except the one we're running on), the routine will hang in the first while() loop until the 8 second timeout occurs. The num_cpus should be set to the number of CPUs specified in the mask passed into the routine, after we've made any modifications to the mask. With this change, we can also get rid of the call to cpus_empty() and avoid adding another pass through the bitmask. Signed-off-by: Kevin Corry Signed-off-by: Carl Love Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 087c92f2a3..1ea43160f5 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -212,11 +212,6 @@ int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic, atomic_set(&data.finished, 0); spin_lock(&call_lock); - /* Must grab online cpu count with preempt disabled, otherwise - * it can change. */ - num_cpus = num_online_cpus() - 1; - if (!num_cpus) - goto done; /* remove 'self' from the map */ if (cpu_isset(smp_processor_id(), map)) @@ -224,7 +219,9 @@ int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic, /* sanity check the map, remove any non-online processors. */ cpus_and(map, map, cpu_online_map); - if (cpus_empty(map)) + + num_cpus = cpus_weight(map); + if (!num_cpus) goto done; call_data = &data;