1 files changed, 41 insertions, 113 deletions

diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c
index 3d897de89061..632762b57299 100644
--- a/kernel/bpf/percpu_freelist.c
+++ b/kernel/bpf/percpu_freelist.c
@@ -14,11 +14,9 @@ int pcpu_freelist_init(struct pcpu_freelist *s)
 	for_each_possible_cpu(cpu) {
 		struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu);
 
-		raw_spin_lock_init(&head->lock);
+		raw_res_spin_lock_init(&head->lock);
 		head->first = NULL;
 	}
-	raw_spin_lock_init(&s->extralist.lock);
-	s->extralist.first = NULL;
 	return 0;
 }
 
@@ -31,63 +29,42 @@ static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head,
 					   struct pcpu_freelist_node *node)
 {
 	node->next = head->first;
-	head->first = node;
+	WRITE_ONCE(head->first, node);
 }
 
-static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
+static inline bool ___pcpu_freelist_push(struct pcpu_freelist_head *head,
 					 struct pcpu_freelist_node *node)
 {
-	raw_spin_lock(&head->lock);
-	pcpu_freelist_push_node(head, node);
-	raw_spin_unlock(&head->lock);
-}
-
-static inline bool pcpu_freelist_try_push_extra(struct pcpu_freelist *s,
-						struct pcpu_freelist_node *node)
-{
-	if (!raw_spin_trylock(&s->extralist.lock))
+	if (raw_res_spin_lock(&head->lock))
 		return false;
-
-	pcpu_freelist_push_node(&s->extralist, node);
-	raw_spin_unlock(&s->extralist.lock);
+	pcpu_freelist_push_node(head, node);
+	raw_res_spin_unlock(&head->lock);
 	return true;
 }
 
-static inline void ___pcpu_freelist_push_nmi(struct pcpu_freelist *s,
-					     struct pcpu_freelist_node *node)
+void __pcpu_freelist_push(struct pcpu_freelist *s,
+			struct pcpu_freelist_node *node)
 {
-	int cpu, orig_cpu;
+	struct pcpu_freelist_head *head;
+	int cpu;
 
-	orig_cpu = cpu = raw_smp_processor_id();
-	while (1) {
-		struct pcpu_freelist_head *head;
+	if (___pcpu_freelist_push(this_cpu_ptr(s->freelist), node))
+		return;
 
-		head = per_cpu_ptr(s->freelist, cpu);
-		if (raw_spin_trylock(&head->lock)) {
+	while (true) {
+		for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) {
+			if (cpu == raw_smp_processor_id())
+				continue;
+			head = per_cpu_ptr(s->freelist, cpu);
+			if (raw_res_spin_lock(&head->lock))
+				continue;
 			pcpu_freelist_push_node(head, node);
-			raw_spin_unlock(&head->lock);
+			raw_res_spin_unlock(&head->lock);
 			return;
 		}
-		cpu = cpumask_next(cpu, cpu_possible_mask);
-		if (cpu >= nr_cpu_ids)
-			cpu = 0;
-
-		/* cannot lock any per cpu lock, try extralist */
-		if (cpu == orig_cpu &&
-		    pcpu_freelist_try_push_extra(s, node))
-			return;
 	}
 }
 
-void __pcpu_freelist_push(struct pcpu_freelist *s,
-			struct pcpu_freelist_node *node)
-{
-	if (in_nmi())
-		___pcpu_freelist_push_nmi(s, node);
-	else
-		___pcpu_freelist_push(this_cpu_ptr(s->freelist), node);
-}
-
 void pcpu_freelist_push(struct pcpu_freelist *s,
 			struct pcpu_freelist_node *node)
 {
@@ -102,98 +79,49 @@ void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
 			    u32 nr_elems)
 {
 	struct pcpu_freelist_head *head;
-	int i, cpu, pcpu_entries;
+	unsigned int cpu, cpu_idx, i, j, n, m;
 
-	pcpu_entries = nr_elems / num_possible_cpus() + 1;
-	i = 0;
+	n = nr_elems / num_possible_cpus();
+	m = nr_elems % num_possible_cpus();
 
+	cpu_idx = 0;
 	for_each_possible_cpu(cpu) {
-again:
 		head = per_cpu_ptr(s->freelist, cpu);
-		/* No locking required as this is not visible yet. */
-		pcpu_freelist_push_node(head, buf);
-		i++;
-		buf += elem_size;
-		if (i == nr_elems)
-			break;
-		if (i % pcpu_entries)
-			goto again;
+		j = n + (cpu_idx < m ? 1 : 0);
+		for (i = 0; i < j; i++) {
+			/* No locking required as this is not visible yet. */
+			pcpu_freelist_push_node(head, buf);
+			buf += elem_size;
+		}
+		cpu_idx++;
 	}
 }
 
 static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s)
 {
+	struct pcpu_freelist_node *node = NULL;
 	struct pcpu_freelist_head *head;
-	struct pcpu_freelist_node *node;
-	int orig_cpu, cpu;
+	int cpu;
 
-	orig_cpu = cpu = raw_smp_processor_id();
-	while (1) {
+	for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) {
 		head = per_cpu_ptr(s->freelist, cpu);
-		raw_spin_lock(&head->lock);
+		if (!READ_ONCE(head->first))
+			continue;
+		if (raw_res_spin_lock(&head->lock))
+			continue;
 		node = head->first;
 		if (node) {
-			head->first = node->next;
-			raw_spin_unlock(&head->lock);
+			WRITE_ONCE(head->first, node->next);
+			raw_res_spin_unlock(&head->lock);
 			return node;
 		}
-		raw_spin_unlock(&head->lock);
-		cpu = cpumask_next(cpu, cpu_possible_mask);
-		if (cpu >= nr_cpu_ids)
-			cpu = 0;
-		if (cpu == orig_cpu)
-			break;
+		raw_res_spin_unlock(&head->lock);
 	}
-
-	/* per cpu lists are all empty, try extralist */
-	raw_spin_lock(&s->extralist.lock);
-	node = s->extralist.first;
-	if (node)
-		s->extralist.first = node->next;
-	raw_spin_unlock(&s->extralist.lock);
-	return node;
-}
-
-static struct pcpu_freelist_node *
-___pcpu_freelist_pop_nmi(struct pcpu_freelist *s)
-{
-	struct pcpu_freelist_head *head;
-	struct pcpu_freelist_node *node;
-	int orig_cpu, cpu;
-
-	orig_cpu = cpu = raw_smp_processor_id();
-	while (1) {
-		head = per_cpu_ptr(s->freelist, cpu);
-		if (raw_spin_trylock(&head->lock)) {
-			node = head->first;
-			if (node) {
-				head->first = node->next;
-				raw_spin_unlock(&head->lock);
-				return node;
-			}
-			raw_spin_unlock(&head->lock);
-		}
-		cpu = cpumask_next(cpu, cpu_possible_mask);
-		if (cpu >= nr_cpu_ids)
-			cpu = 0;
-		if (cpu == orig_cpu)
-			break;
-	}
-
-	/* cannot pop from per cpu lists, try extralist */
-	if (!raw_spin_trylock(&s->extralist.lock))
-		return NULL;
-	node = s->extralist.first;
-	if (node)
-		s->extralist.first = node->next;
-	raw_spin_unlock(&s->extralist.lock);
 	return node;
 }
 
 struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
 {
-	if (in_nmi())
-		return ___pcpu_freelist_pop_nmi(s);
 	return ___pcpu_freelist_pop(s);
 }