[v08,1/5] hotplug/cpu: Conditionally acquire/release DRC index

Message ID c02a88cf-5b98-aaf3-1630-91b399ebbf65@linux.vnet.ibm.com
State New
Headers show
Series
  • powerpc/hotplug: Update affinity for migrated CPUs
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Commit Message

Michael Bringmann July 29, 2018, 1:19 p.m.
powerpc/cpu: Modify dlpar_cpu_add and dlpar_cpu_remove to allow the
skipping of DRC index acquire or release operations during the CPU
add or remove operations.  This is intended to support subsequent
changes to provide a 'CPU readd' operation.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
---
Changes in patch:
  -- Move new validity check added to pseries_smp_notifier
     to another patch
  -- Revise one of checks for 'acquire_drc' in dlpar_cpu_add.
  -- Revise one of checks for 'release_drc' in dlpar_cpu_remove.
---
 arch/powerpc/platforms/pseries/hotplug-cpu.c |   71 +++++++++++++++-----------
 1 file changed, 40 insertions(+), 31 deletions(-)

Patch

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 6ef77ca..7ede3b0 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -432,7 +432,7 @@  static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
 	return found;
 }
 
-static ssize_t dlpar_cpu_add(u32 drc_index)
+static ssize_t dlpar_cpu_add(u32 drc_index, bool acquire_drc)
 {
 	struct device_node *dn, *parent;
 	int rc, saved_rc;
@@ -457,19 +457,22 @@  static ssize_t dlpar_cpu_add(u32 drc_index)
 		return -EINVAL;
 	}
 
-	rc = dlpar_acquire_drc(drc_index);
-	if (rc) {
-		pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
-			rc, drc_index);
-		of_node_put(parent);
-		return -EINVAL;
+	if (acquire_drc) {
+		rc = dlpar_acquire_drc(drc_index);
+		if (rc) {
+			pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
+				rc, drc_index);
+			of_node_put(parent);
+			return -EINVAL;
+		}
 	}
 
 	dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
 	if (!dn) {
 		pr_warn("Failed call to configure-connector, drc index: %x\n",
 			drc_index);
-		dlpar_release_drc(drc_index);
+		if (acquire_drc)
+			dlpar_release_drc(drc_index);
 		of_node_put(parent);
 		return -EINVAL;
 	}
@@ -484,9 +487,11 @@  static ssize_t dlpar_cpu_add(u32 drc_index)
 		pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n",
 			dn->name, rc, drc_index);
 
-		rc = dlpar_release_drc(drc_index);
-		if (!rc)
-			dlpar_free_cc_nodes(dn);
+		if (acquire_drc) {
+			rc = dlpar_release_drc(drc_index);
+			if (!rc)
+				dlpar_free_cc_nodes(dn);
+		}
 
 		return saved_rc;
 	}
@@ -498,7 +503,7 @@  static ssize_t dlpar_cpu_add(u32 drc_index)
 			dn->name, rc, drc_index);
 
 		rc = dlpar_detach_node(dn);
-		if (!rc)
+		if (!rc && acquire_drc)
 			dlpar_release_drc(drc_index);
 
 		return saved_rc;
@@ -566,7 +571,8 @@  static int dlpar_offline_cpu(struct device_node *dn)
 
 }
 
-static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
+static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index,
+				bool release_drc)
 {
 	int rc;
 
@@ -579,12 +585,14 @@  static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
 		return -EINVAL;
 	}
 
-	rc = dlpar_release_drc(drc_index);
-	if (rc) {
-		pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
-			drc_index, dn->name, rc);
-		dlpar_online_cpu(dn);
-		return rc;
+	if (release_drc) {
+		rc = dlpar_release_drc(drc_index);
+		if (rc) {
+			pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
+				drc_index, dn->name, rc);
+			dlpar_online_cpu(dn);
+			return rc;
+		}
 	}
 
 	rc = dlpar_detach_node(dn);
@@ -593,8 +601,9 @@  static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
 
 		pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc);
 
-		rc = dlpar_acquire_drc(drc_index);
-		if (!rc)
+		if (release_drc)
+			rc = dlpar_acquire_drc(drc_index);
+		if (!release_drc || !rc)
 			dlpar_online_cpu(dn);
 
 		return saved_rc;
@@ -622,7 +631,7 @@  static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
 	return dn;
 }
 
-static int dlpar_cpu_remove_by_index(u32 drc_index)
+static int dlpar_cpu_remove_by_index(u32 drc_index, bool release_drc)
 {
 	struct device_node *dn;
 	int rc;
@@ -634,7 +643,7 @@  static int dlpar_cpu_remove_by_index(u32 drc_index)
 		return -ENODEV;
 	}
 
-	rc = dlpar_cpu_remove(dn, drc_index);
+	rc = dlpar_cpu_remove(dn, drc_index, release_drc);
 	of_node_put(dn);
 	return rc;
 }
@@ -699,7 +708,7 @@  static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
 	}
 
 	for (i = 0; i < cpus_to_remove; i++) {
-		rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
+		rc = dlpar_cpu_remove_by_index(cpu_drcs[i], true);
 		if (rc)
 			break;
 
@@ -710,7 +719,7 @@  static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
 		pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
 
 		for (i = 0; i < cpus_removed; i++)
-			dlpar_cpu_add(cpu_drcs[i]);
+			dlpar_cpu_add(cpu_drcs[i], true);
 
 		rc = -EINVAL;
 	} else {
@@ -780,7 +789,7 @@  static int dlpar_cpu_add_by_count(u32 cpus_to_add)
 	}
 
 	for (i = 0; i < cpus_to_add; i++) {
-		rc = dlpar_cpu_add(cpu_drcs[i]);
+		rc = dlpar_cpu_add(cpu_drcs[i], true);
 		if (rc)
 			break;
 
@@ -791,7 +800,7 @@  static int dlpar_cpu_add_by_count(u32 cpus_to_add)
 		pr_warn("CPU hot-add failed, removing any added CPUs\n");
 
 		for (i = 0; i < cpus_added; i++)
-			dlpar_cpu_remove_by_index(cpu_drcs[i]);
+			dlpar_cpu_remove_by_index(cpu_drcs[i], true);
 
 		rc = -EINVAL;
 	} else {
@@ -817,7 +826,7 @@  int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
 		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
 			rc = dlpar_cpu_remove_by_count(count);
 		else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
-			rc = dlpar_cpu_remove_by_index(drc_index);
+			rc = dlpar_cpu_remove_by_index(drc_index, true);
 		else
 			rc = -EINVAL;
 		break;
@@ -825,7 +834,7 @@  int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
 		if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
 			rc = dlpar_cpu_add_by_count(count);
 		else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
-			rc = dlpar_cpu_add(drc_index);
+			rc = dlpar_cpu_add(drc_index, true);
 		else
 			rc = -EINVAL;
 		break;
@@ -850,7 +859,7 @@  static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
 	if (rc)
 		return -EINVAL;
 
-	rc = dlpar_cpu_add(drc_index);
+	rc = dlpar_cpu_add(drc_index, true);
 
 	return rc ? rc : count;
 }
@@ -871,7 +880,7 @@  static ssize_t dlpar_cpu_release(const char *buf, size_t count)
 		return -EINVAL;
 	}
 
-	rc = dlpar_cpu_remove(dn, drc_index);
+	rc = dlpar_cpu_remove(dn, drc_index, true);
 	of_node_put(dn);
 
 	return rc ? rc : count;