[PATCH 2/2] drivers/perf: hisi: add NULL check for name

[Junhao He]

When allocations fails that can be NULL now.

If the name provided is NULL, then the initialization process of the PMU
type and dev will be skipped in function perf_pmu_register().
Consequently, the PMU will not be able to register into the kernel.
Moreover, in the case of unregister the PMU, the function device_del()
will need to handle NULL pointers, which potentially can cause issues.

So move this allocation above the cpuhp_state_add_instance() and directly
return if it does fail.

Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
---
 drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c | 17 ++++++++++-------
 drivers/perf/hisilicon/hisi_uncore_hha_pmu.c  |  7 +++++--
 drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c  | 11 +++++------
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c b/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c
index 8a3d74ddcd6d..ffb039d05d07 100644
--- a/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_ddrc_pmu.c
@@ -499,13 +499,6 @@ static int hisi_ddrc_pmu_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE,
-				       &ddrc_pmu->node);
-	if (ret) {
-		dev_err(&pdev->dev, "Error %d registering hotplug;\n", ret);
-		return ret;
-	}
-
 	if (ddrc_pmu->identifier >= HISI_PMU_V2)
 		name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
 				      "hisi_sccl%u_ddrc%u_%u",
@@ -516,6 +509,16 @@ static int hisi_ddrc_pmu_probe(struct platform_device *pdev)
 				      "hisi_sccl%u_ddrc%u", ddrc_pmu->sccl_id,
 				      ddrc_pmu->index_id);
 
+	if (!name)
+		return -ENOMEM;
+
+	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_DDRC_ONLINE,
+				       &ddrc_pmu->node);
+	if (ret) {
+		dev_err(&pdev->dev, "Error %d registering hotplug;\n", ret);
+		return ret;
+	}
+
 	hisi_pmu_init(ddrc_pmu, THIS_MODULE);
 
 	ret = perf_pmu_register(&ddrc_pmu->pmu, name, -1);
diff --git a/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c b/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c
index 5701a84edb0e..15caf99e1eef 100644
--- a/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_hha_pmu.c
@@ -510,6 +510,11 @@ static int hisi_hha_pmu_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_hha%u",
+			      hha_pmu->sccl_id, hha_pmu->index_id);
+	if (!name)
+		return -ENOMEM;
+
 	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_HHA_ONLINE,
 				       &hha_pmu->node);
 	if (ret) {
@@ -517,8 +522,6 @@ static int hisi_hha_pmu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_hha%u",
-			      hha_pmu->sccl_id, hha_pmu->index_id);
 	hisi_pmu_init(hha_pmu, THIS_MODULE);
 
 	ret = perf_pmu_register(&hha_pmu->pmu, name, -1);
diff --git a/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c b/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c
index 68596b566344..794dbcd19b7a 100644
--- a/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_l3c_pmu.c
@@ -544,6 +544,11 @@ static int hisi_l3c_pmu_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_l3c%u",
+			      l3c_pmu->sccl_id, l3c_pmu->ccl_id);
+	if (!name)
+		return -ENOMEM;
+
 	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_ARM_HISI_L3_ONLINE,
 				       &l3c_pmu->node);
 	if (ret) {
@@ -551,12 +556,6 @@ static int hisi_l3c_pmu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	/*
-	 * CCL_ID is used to identify the L3C in the same SCCL which was
-	 * used _UID by mistake.
-	 */
-	name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "hisi_sccl%u_l3c%u",
-			      l3c_pmu->sccl_id, l3c_pmu->ccl_id);
 	hisi_pmu_init(l3c_pmu, THIS_MODULE);
 
 	ret = perf_pmu_register(&l3c_pmu->pmu, name, -1);
-- 
2.33.0