Add CPU hotplug support for PAI PMU

index cdb8006220ca..7c13f5586c79 100644
@@ -140,16 +140,14 @@ static void pai_free(struct pai_mapptr *mp)
 /* Adjust usage counters and remove allocated memory when all users are
  * gone.
  */
-static void pai_event_destroy_cpu(struct perf_event *event, int cpu)
+static void pai_event_destroy_cpu(int idx, int cpu)
 {
-	int idx = PAI_PMU_IDX(event);
 	struct pai_mapptr *mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);
 	struct pai_map *cpump = mp->mapptr;
 
 	mutex_lock(&pai_reserve_mutex);
-	debug_sprintf_event(paidbg, 5, "%s event %#llx idx %d cpu %d users %d "
-			    "refcnt %u\n", __func__, event->attr.config, idx,
-			    event->cpu, cpump->active_events,
+	debug_sprintf_event(paidbg, 5, "%s users %d refcnt %u\n",
+			    __func__, cpump->active_events,
 			    refcount_read(&cpump->refcnt));
 	if (refcount_dec_and_test(&cpump->refcnt))
 		pai_free(mp);

@@ -159,17 +157,17 @@ static void pai_event_destroy_cpu(struct perf_event *event, int cpu)
 
 static void pai_event_destroy(struct perf_event *event)
 {
-	int cpu;
+	int cpu = 0, idx = PAI_PMU_IDX(event);
 
 	free_page(PAI_SAVE_AREA(event));
 	if (event->cpu == -1) {
 		struct cpumask *mask = PAI_CPU_MASK(event);
 
 		for_each_cpu(cpu, mask)
-			pai_event_destroy_cpu(event, cpu);
+			pai_event_destroy_cpu(idx, cpu);
 		kfree(mask);
 	} else {
-		pai_event_destroy_cpu(event, event->cpu);
+		pai_event_destroy_cpu(idx, event->cpu);
 	}
 }
 

@@ -241,12 +239,12 @@ static u64 paicrypt_getall(struct perf_event *event)
  *
  * Allocate the memory for the event.
  */
-static int pai_alloc_cpu(struct perf_event *event, int cpu)
+static int pai_alloc_cpu(int idx, int cpu)
 {
-	int rc, idx = PAI_PMU_IDX(event);
 	struct pai_map *cpump = NULL;
 	bool need_paiext_cb = false;
 	struct pai_mapptr *mp;
+	int rc;
 
 	mutex_lock(&pai_reserve_mutex);
 	/* Allocate root node */

@@ -318,6 +316,7 @@ static int pai_alloc_cpu(struct perf_event *event, int cpu)
 
 static int pai_alloc(struct perf_event *event)
 {
+	int idx = PAI_PMU_IDX(event);
 	struct cpumask *maskptr;
 	int cpu, rc = -ENOMEM;
 

@@ -326,10 +325,10 @@ static int pai_alloc(struct perf_event *event)
 		goto out;
 
 	for_each_online_cpu(cpu) {
-		rc = pai_alloc_cpu(event, cpu);
+		rc = pai_alloc_cpu(idx, cpu);
 		if (rc) {
 			for_each_cpu(cpu, maskptr)
-				pai_event_destroy_cpu(event, cpu);
+				pai_event_destroy_cpu(idx, cpu);
 			kfree(maskptr);
 			goto out;
 		}

@@ -392,7 +391,7 @@ static int pai_event_init(struct perf_event *event, int idx)
 	}
 
 	if (event->cpu >= 0)
-		rc = pai_alloc_cpu(event, event->cpu);
+		rc = pai_alloc_cpu(idx, event->cpu);
 	else
 		rc = pai_alloc(event);
 	if (rc) {

index 7c13f5586c79..52d9f654346a 100644
@@ -138,21 +138,19 @@ static void pai_free(struct pai_mapptr *mp)
 }
 
 /* Adjust usage counters and remove allocated memory when all users are
- * gone.
+ * gone. Called under mutex_lock.
  */
 static void pai_event_destroy_cpu(int idx, int cpu)
 {
 	struct pai_mapptr *mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);
 	struct pai_map *cpump = mp->mapptr;
 
-	mutex_lock(&pai_reserve_mutex);
 	debug_sprintf_event(paidbg, 5, "%s users %d refcnt %u\n",
 			    __func__, cpump->active_events,
 			    refcount_read(&cpump->refcnt));
 	if (refcount_dec_and_test(&cpump->refcnt))
 		pai_free(mp);
 	pai_root_free(idx);
-	mutex_unlock(&pai_reserve_mutex);
 }
 
 static void pai_event_destroy(struct perf_event *event)

@@ -160,6 +158,7 @@ static void pai_event_destroy(struct perf_event *event)
 	int cpu = 0, idx = PAI_PMU_IDX(event);
 
 	free_page(PAI_SAVE_AREA(event));
+	mutex_lock(&pai_reserve_mutex);
 	if (event->cpu == -1) {
 		struct cpumask *mask = PAI_CPU_MASK(event);
 

@@ -169,6 +168,7 @@ static void pai_event_destroy(struct perf_event *event)
 	} else {
 		pai_event_destroy_cpu(idx, event->cpu);
 	}
+	mutex_unlock(&pai_reserve_mutex);
 }
 
 static void paicrypt_event_destroy(struct perf_event *event)

@@ -232,12 +232,10 @@ static u64 paicrypt_getall(struct perf_event *event)
 	return sum;
 }
 
-/* Check concurrent access of counting and sampling for crypto events.
- * This function is called in process context and it is save to block.
- * When the event initialization functions fails, no other call back will
- * be invoked.
- *
- * Allocate the memory for the event.
+/* Allocate all per-CPU data structures. This function is called in
+ * process context and can block. In case of error all partly allocated
+ * memory is released and the reference counters adjusted correctly.
+ * Called under mutex_lock.
  */
 static int pai_alloc_cpu(int idx, int cpu)
 {

@@ -246,11 +244,10 @@ static int pai_alloc_cpu(int idx, int cpu)
 	struct pai_mapptr *mp;
 	int rc;
 
-	mutex_lock(&pai_reserve_mutex);
 	/* Allocate root node */
 	rc = pai_root_alloc(idx);
 	if (rc)
-		goto unlock;
+		goto out;
 
 	/* Allocate node for this event */
 	mp = per_cpu_ptr(pai_root[idx].mapptr, cpu);

@@ -308,12 +305,12 @@ static int pai_alloc_cpu(int idx, int cpu)
 		 */
 		pai_root_free(idx);
 	}
-unlock:
-	mutex_unlock(&pai_reserve_mutex);
+out:
 	/* If rc is non-zero, no increment of counter/sampler was done. */
 	return rc;
 }
 
+/* Called under mutex_lock */
 static int pai_alloc(struct perf_event *event)
 {
 	int idx = PAI_PMU_IDX(event);

@@ -390,10 +387,12 @@ static int pai_event_init(struct perf_event *event, int idx)
 		}
 	}
 
+	mutex_lock(&pai_reserve_mutex);
 	if (event->cpu >= 0)
 		rc = pai_alloc_cpu(idx, event->cpu);
 	else
 		rc = pai_alloc(event);
+	mutex_unlock(&pai_reserve_mutex);
 	if (rc) {
 		free_page(PAI_SAVE_AREA(event));
 		goto out;

index 534d0320e2aa..a3456a36aaa7 100644
@@ -76,7 +76,6 @@ static __always_inline void pai_kernel_exit(struct pt_regs *regs)
 }
 
 #define PAI_SAVE_AREA(x)	((x)->hw.event_base)
-#define PAI_CPU_MASK(x)		((x)->hw.addr_filters)
 #define PAI_PMU_IDX(x)		((x)->hw.last_tag)
 #define PAI_SWLIST(x)		(&(x)->hw.tp_list)
 

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