[PATCH v2 2/2] perf/smmuv3: Fix hotplug callback leak in arm_smmu_pmu_init()

[Shang XiaoJing]

arm_smmu_pmu_init() won't remove the callback added by
cpuhp_setup_state_multi() when platform_driver_register() failed. Remove
the callback by cpuhp_remove_multi_state() in fail path.

Similar to the handling of arm_ccn_init() in commit 26242b330093 ("bus:
arm-ccn: Prevent hotplug callback leak")

Fixes: 7d839b4b9e00 ("perf/smmuv3: Add arm64 smmuv3 pmu driver")
Signed-off-by: Shang XiaoJing <shangxiaojing at huawei.com>
Reviewed-by: Punit Agrawal <punit.agrawal at bytedance.com>
---
changes in v2:
- use one instead of two separate returns.
---
 drivers/perf/arm_smmuv3_pmu.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
index 00d4c45a8017..25a269d431e4 100644
--- a/drivers/perf/arm_smmuv3_pmu.c
+++ b/drivers/perf/arm_smmuv3_pmu.c
@@ -959,6 +959,8 @@ static struct platform_driver smmu_pmu_driver = {
 
 static int __init arm_smmu_pmu_init(void)
 {
+	int ret;
+
 	cpuhp_state_num = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
 						  "perf/arm/pmcg:online",
 						  NULL,
@@ -966,7 +968,11 @@ static int __init arm_smmu_pmu_init(void)
 	if (cpuhp_state_num < 0)
 		return cpuhp_state_num;
 
-	return platform_driver_register(&smmu_pmu_driver);
+	ret = platform_driver_register(&smmu_pmu_driver);
+	if (ret)
+		cpuhp_remove_multi_state(cpuhp_state_num);
+
+	return ret;
 }
 module_init(arm_smmu_pmu_init);
 
-- 
2.17.1