From: Wang Hui <john.wanghui@huawei.com>
Date: Thu, 22 Feb 2018 19:26:03 -0800
Subject: x86/intel_rdt: Fix incorrect returned value when creating rdgroup
 sub-directory in resctrl file system
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Git-commit: 36e74d355297dde6e69a39c838d24710e442babe
Patch-mainline: v4.16-rc3
References: bsc#1110006

If no monitoring feature is detected because all monitoring features are
disabled during boot time or there is no monitoring feature in hardware,
creating rdtgroup sub-directory by "mkdir" command reports error:

  mkdir: cannot create directory ‘/sys/fs/resctrl/p1’: No such file or directory

But the sub-directory actually is generated and content is correct:

  cpus  cpus_list  schemata  tasks

The error is because rdtgroup_mkdir_ctrl_mon() returns non zero value after
the sub-directory is created and the returned value is reported as an error
to user.

Clear the returned value to report to user that the sub-directory is
actually created successfully.

Signed-off-by: Wang Hui <john.wanghui@huawei.com>
Signed-off-by: Zhang Yanfei <yanfei.zhang@huawei.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vikas <vikas.shivappa@intel.com>
Cc: Xiaochen Shen <xiaochen.shen@intel.com>
Link: http://lkml.kernel.org/r/1519356363-133085-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index bdab7d2f51af..fca759d272a1 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1804,6 +1804,7 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 		goto out_common_fail;
 	}
 	closid = ret;
+	ret = 0;
 
 	rdtgrp->closid = closid;
 	list_add(&rdtgrp->rdtgroup_list, &rdt_all_groups);