Subject: [PATCH 3/6] pseries: Update CPU hotplug error recovery

From: Nathan Fontenot <[email-masked]>
Date: Mon, 22 Jun 2015 15:59:20 -0500

Update the cpu dlpar add/remove paths to do better error recovery when 
a failure occurs during the add/remove operation. This includes adding
some pr_info and pr_debug statements.

Signed-off-by: Nathan Fontenot <[email-masked]>
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c |   34 +++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index f58d902..7890b2f 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -18,6 +18,8 @@
  *      2 of the License, or (at your option) any later version.
  */
 
+#define pr_fmt(fmt)     "pseries-hotplug-cpu: " fmt
+
 #include <linux/kernel.h>
 #include <linux/interrupt.h>
 #include <linux/delay.h>
@@ -386,22 +388,35 @@ static ssize_t dlpar_cpu_add(struct device_node *parent, u32 drc_index)
 	struct device_node *dn;
 	int rc;
 
+	pr_info("Attempting to add CPU, drc index %x\n", drc_index);
+
 	rc = dlpar_acquire_drc(drc_index);
 	if (rc)
 		return -EINVAL;
 
 	dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
-	if (!dn)
+	if (!dn) {
+		pr_debug("Failed call to configure-connector\n");
+		dlpar_release_drc(drc_index);
 		return -EINVAL;
+	}
 
 	rc = dlpar_attach_node(dn);
 	if (rc) {
+		pr_debug("Failed to attach node (%d)\n", rc);
 		dlpar_release_drc(drc_index);
 		dlpar_free_cc_nodes(dn);
 		return rc;
 	}
 
 	rc = dlpar_online_cpu(dn);
+	if (rc) {
+		pr_debug("Failed to online cpu (%d)\n", rc);
+		dlpar_detach_node(dn);
+		dlpar_release_drc(drc_index);
+	}
+
+	pr_info("Successfully added CPU, drc index %x\n", drc_index);
 	return rc;
 }
 
@@ -465,18 +480,29 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
 {
 	int rc;
 
+	pr_info("Attemping to remove CPU, drc index %x\n", drc_index);
+
 	rc = dlpar_offline_cpu(dn);
-	if (rc)
+	if (rc) {
+		pr_debug("Failed top offline cpu (%d)\n", rc);
 		return -EINVAL;
+	}
 
 	rc = dlpar_release_drc(drc_index);
-	if (rc)
+	if (rc) {
+		pr_debug("Failed to release drc (%d)\n", rc);
+		dlpar_online_cpu(dn);
 		return rc;
+	}
 
 	rc = dlpar_detach_node(dn);
-	if (rc)
+	if (rc) {
+		pr_debug("Failed to detach cpu node (%d)\n", rc);
 		dlpar_acquire_drc(drc_index);
+		dlpar_online_cpu(dn);
+	}
 
+	pr_info("Successfully removed CPU, drc index %x\n", drc_index);
 	return rc;
 }