@@ -25,12 +25,18 @@ void pcpu_freelist_destroy(struct pcpu_f
free_percpu(s->freelist);
}
+static inline void pcpu_freelist_push_node(struct pcpu_freelist_head *head,
+ struct pcpu_freelist_node *node)
+{
+ node->next = head->first;
+ head->first = 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;
- head->first = node;
+ pcpu_freelist_push_node(head, node);
raw_spin_unlock(&head->lock);
}
@@ -56,21 +62,16 @@ void pcpu_freelist_populate(struct pcpu_
u32 nr_elems)
{
struct pcpu_freelist_head *head;
- unsigned long flags;
int i, cpu, pcpu_entries;
pcpu_entries = nr_elems / num_possible_cpus() + 1;
i = 0;
- /* disable irq to workaround lockdep false positive
- * in bpf usage pcpu_freelist_populate() will never race
- * with pcpu_freelist_push()
- */
- local_irq_save(flags);
for_each_possible_cpu(cpu) {
again:
head = per_cpu_ptr(s->freelist, cpu);
- ___pcpu_freelist_push(head, buf);
+ /* No locking required as this is not visible yet. */
+ pcpu_freelist_push_node(head, buf);
i++;
buf += elem_size;
if (i == nr_elems)
@@ -78,7 +79,6 @@ void pcpu_freelist_populate(struct pcpu_
if (i % pcpu_entries)
goto again;
}
- local_irq_restore(flags);
}
struct pcpu_freelist_node *__pcpu_freelist_pop(struct pcpu_freelist *s)
pcpu_freelist_populate() is disabling interrupts and then iterates over the possible CPUs. The reason why this disables interrupts is to silence lockdep because the invoked ___pcpu_freelist_push() takes spin locks. Neither the interrupt disabling nor the locking are required in this function because it's called during initialization and the resulting map is not yet visible to anything. Split out the actual push assignement into an inline, call it from the loop and remove the interrupt disable. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- kernel/bpf/percpu_freelist.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)