cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus()
Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use
get_online_cpus and put_online_cpus instead as it highlights the
refcount semantics in these operations.
The new API guarantees protection against the cpu-hotplug operation, but
it doesn't guarantee serialized access to any of the local data
structures. Hence the changes needs to be reviewed.
In case of pseries_add_processor/pseries_remove_processor, use
cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the
cpu_present_map there.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c
index 892665b..bb4f00c 100644
--- a/arch/mips/kernel/mips-mt-fpaff.c
+++ b/arch/mips/kernel/mips-mt-fpaff.c
@@ -58,13 +58,13 @@
if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
return -EFAULT;
- lock_cpu_hotplug();
+ get_online_cpus();
read_lock(&tasklist_lock);
p = find_process_by_pid(pid);
if (!p) {
read_unlock(&tasklist_lock);
- unlock_cpu_hotplug();
+ put_online_cpus();
return -ESRCH;
}
@@ -106,7 +106,7 @@
out_unlock:
put_task_struct(p);
- unlock_cpu_hotplug();
+ put_online_cpus();
return retval;
}
@@ -125,7 +125,7 @@
if (len < real_len)
return -EINVAL;
- lock_cpu_hotplug();
+ get_online_cpus();
read_lock(&tasklist_lock);
retval = -ESRCH;
@@ -140,7 +140,7 @@
out_unlock:
read_unlock(&tasklist_lock);
- unlock_cpu_hotplug();
+ put_online_cpus();
if (retval)
return retval;
if (copy_to_user(user_mask_ptr, &mask, real_len))