Doing:
echo 0 >cpu1/online
echo 1 >cpu1/online
on a managed CPU will result in:
Jul 22 15:15:37 linux kernel: [ 80.013864] WARNING: at fs/sysfs/dir.c:487 sysfs_add_one+0xcf/0xe6()
Jul 22 15:15:37 linux kernel: [ 80.013866] Hardware name: To Be Filled By O.E.M.
Jul 22 15:15:37 linux kernel: [ 80.013868] sysfs: cannot create duplicate filename '/devices/system/cpu/cpu1/cpufreq'
Jul 22 15:15:37 linux kernel: [ 80.013870] Modules linked in: powernow_k8
Jul 22 15:15:37 linux kernel: [ 80.013874] Pid: 5750, comm: bash Not tainted 2.6.31-rc2 #40
Jul 22 15:15:37 linux kernel: [ 80.013876] Call Trace:
Jul 22 15:15:37 linux kernel: [ 80.013879] [<ffffffff8112ebda>] ? sysfs_add_one+0xcf/0xe6
Jul 22 15:15:37 linux kernel: [ 80.013884] [<ffffffff81041926>] warn_slowpath_common+0x77/0xa4
Jul 22 15:15:37 linux kernel: [ 80.013888] [<ffffffff810419a0>] warn_slowpath_fmt+0x3c/0x3e
Jul 22 15:15:37 linux kernel: [ 80.013891] [<ffffffff8112ebda>] sysfs_add_one+0xcf/0xe6
Jul 22 15:15:37 linux kernel: [ 80.013894] [<ffffffff8112f213>] create_dir+0x58/0x87
Jul 22 15:15:37 linux kernel: [ 80.013898] [<ffffffff8112f27a>] sysfs_create_dir+0x38/0x4f
Jul 22 15:15:37 linux kernel: [ 80.013902] [<ffffffff811ffb8a>] kobject_add_internal+0x11f/0x1de
Jul 22 15:15:37 linux kernel: [ 80.013905] [<ffffffff811ffd21>] kobject_add_varg+0x41/0x4e
Jul 22 15:15:37 linux kernel: [ 80.013908] [<ffffffff811ffd7a>] kobject_init_and_add+0x4c/0x57
Jul 22 15:15:37 linux kernel: [ 80.013913] [<ffffffff810667bc>] ? mark_lock+0x22/0x228
Jul 22 15:15:37 linux kernel: [ 80.013918] [<ffffffff813e8a3b>] cpufreq_add_dev_interface+0x40/0x1e4
...
This bug slipped in by git commit:
150b06f7f223cfd0f808737a5243cceca8ea47fa
When splitting up cpufreq_add_dev, the whole cpufreq_add_dev function
is not left anymore, only cpufreq_add_dev_policy.
This patch should reconstruct the identical functionality again as it
was before the split.
CC: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
CC: Dave Jones <davej@xxxxxxxxxx>
Signed-off-by: Thomas Renninger <trenn@xxxxxxx>
---
drivers/cpufreq/cpufreq.c | 20 +++++++++++++++++---
1 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 18c6640..5f37022 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -756,7 +756,12 @@ static struct kobj_type ktype_cpufreq = {
.release = cpufreq_sysfs_release,
};
-
+/*
+ * Returns:
+ * Negative: Failure
+ * 0: Success
+ * Positive: When we have a managed CPU and the sysfs got symlinked
+ */
int cpufreq_add_dev_policy(unsigned int cpu, struct cpufreq_policy *policy,
struct sys_device *sys_dev)
{
@@ -817,7 +822,11 @@ int cpufreq_add_dev_policy(unsigned int cpu, struct cpufreq_policy *policy,
*/
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
- return ret;
+
+ if (!ret)
+ return 1;
+ else
+ return ret;
}
}
#endif
@@ -999,8 +1008,13 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
CPUFREQ_START, policy);
ret = cpufreq_add_dev_policy(cpu, policy, sys_dev);
- if (ret)
+ if (ret) {
+ if (ret > 0)
+ /* This is a managed cpu, symlink created,
+ exit with 0 */
+ ret = 0;
goto err_unlock_policy;
+ }
ret = cpufreq_add_dev_interface(cpu, policy, sys_dev);
if (ret)
--
1.6.0.2
--
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