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authorGary Lin <glin@suse.com>2019-02-15 17:27:57 +0800
committerGary Lin <glin@suse.com>2019-02-15 17:28:23 +0800
commit3e3e8289159eb7a11d469d859f22fdd7623900e3 (patch)
treeeb801f881f43dcb0d60522647c400d0ac0f97012
parent885b807a6c73faab7e6e6acf04b89f15e75baa47 (diff)
bpf: fix lockdep false positive in percpu_freelist
(bsc#1083647). suse-commit: a5600bf29f3cb0b688ddb611ff650fe28b2ff146
-rw-r--r--kernel/bpf/hashtab.c4
-rw-r--r--kernel/bpf/percpu_freelist.c41
-rw-r--r--kernel/bpf/percpu_freelist.h4
3 files changed, 35 insertions, 14 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 9e0f35809f6b..762bc8ce40e6 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -650,7 +650,7 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
}
if (htab_is_prealloc(htab)) {
- pcpu_freelist_push(&htab->freelist, &l->fnode);
+ __pcpu_freelist_push(&htab->freelist, &l->fnode);
} else {
atomic_dec(&htab->count);
l->htab = htab;
@@ -712,7 +712,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
} else {
struct pcpu_freelist_node *l;
- l = pcpu_freelist_pop(&htab->freelist);
+ l = __pcpu_freelist_pop(&htab->freelist);
if (!l)
return ERR_PTR(-E2BIG);
l_new = container_of(l, struct htab_elem, fnode);
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c
index 673fa6fe2d73..0c1b4ba9e90e 100644
--- a/kernel/bpf/percpu_freelist.c
+++ b/kernel/bpf/percpu_freelist.c
@@ -28,8 +28,8 @@ void pcpu_freelist_destroy(struct pcpu_freelist *s)
free_percpu(s->freelist);
}
-static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
- struct pcpu_freelist_node *node)
+static inline void ___pcpu_freelist_push(struct pcpu_freelist_head *head,
+ struct pcpu_freelist_node *node)
{
raw_spin_lock(&head->lock);
node->next = head->first;
@@ -37,12 +37,22 @@ static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
raw_spin_unlock(&head->lock);
}
-void pcpu_freelist_push(struct pcpu_freelist *s,
+void __pcpu_freelist_push(struct pcpu_freelist *s,
struct pcpu_freelist_node *node)
{
struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist);
- __pcpu_freelist_push(head, node);
+ ___pcpu_freelist_push(head, node);
+}
+
+void pcpu_freelist_push(struct pcpu_freelist *s,
+ struct pcpu_freelist_node *node)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ __pcpu_freelist_push(s, node);
+ local_irq_restore(flags);
}
void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
@@ -63,7 +73,7 @@ void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
for_each_possible_cpu(cpu) {
again:
head = per_cpu_ptr(s->freelist, cpu);
- __pcpu_freelist_push(head, buf);
+ ___pcpu_freelist_push(head, buf);
i++;
buf += elem_size;
if (i == nr_elems)
@@ -74,14 +84,12 @@ again:
local_irq_restore(flags);
}
-struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
{
struct pcpu_freelist_head *head;
struct pcpu_freelist_node *node;
- unsigned long flags;
int orig_cpu, cpu;
- local_irq_save(flags);
orig_cpu = cpu = raw_smp_processor_id();
while (1) {
head = per_cpu_ptr(s->freelist, cpu);
@@ -89,16 +97,25 @@ struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
node = head->first;
if (node) {
head->first = node->next;
- raw_spin_unlock_irqrestore(&head->lock, flags);
+ 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) {
- local_irq_restore(flags);
+ if (cpu == orig_cpu)
return NULL;
- }
}
}
+
+struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
+{
+ struct pcpu_freelist_node *ret;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ ret = __pcpu_freelist_pop(s);
+ local_irq_restore(flags);
+ return ret;
+}
diff --git a/kernel/bpf/percpu_freelist.h b/kernel/bpf/percpu_freelist.h
index 3049aae8ea1e..c3960118e617 100644
--- a/kernel/bpf/percpu_freelist.h
+++ b/kernel/bpf/percpu_freelist.h
@@ -22,8 +22,12 @@ struct pcpu_freelist_node {
struct pcpu_freelist_node *next;
};
+/* pcpu_freelist_* do spin_lock_irqsave. */
void pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *);
+/* __pcpu_freelist_* do spin_lock only. caller must disable irqs. */
+void __pcpu_freelist_push(struct pcpu_freelist *, struct pcpu_freelist_node *);
+struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *);
void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
u32 nr_elems);
int pcpu_freelist_init(struct pcpu_freelist *);