diff options
Diffstat (limited to 'kernel/bpf/percpu_freelist.c')
| -rw-r--r-- | kernel/bpf/percpu_freelist.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c index 3d897de89061..00b874c8e889 100644 --- a/kernel/bpf/percpu_freelist.c +++ b/kernel/bpf/percpu_freelist.c @@ -31,7 +31,7 @@ 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, @@ -130,14 +130,17 @@ static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s) orig_cpu = cpu = raw_smp_processor_id(); while (1) { head = per_cpu_ptr(s->freelist, cpu); + if (!READ_ONCE(head->first)) + goto next_cpu; raw_spin_lock(&head->lock); node = head->first; if (node) { - head->first = node->next; + WRITE_ONCE(head->first, node->next); raw_spin_unlock(&head->lock); return node; } raw_spin_unlock(&head->lock); +next_cpu: cpu = cpumask_next(cpu, cpu_possible_mask); if (cpu >= nr_cpu_ids) cpu = 0; @@ -146,10 +149,12 @@ static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s) } /* per cpu lists are all empty, try extralist */ + if (!READ_ONCE(s->extralist.first)) + return NULL; raw_spin_lock(&s->extralist.lock); node = s->extralist.first; if (node) - s->extralist.first = node->next; + WRITE_ONCE(s->extralist.first, node->next); raw_spin_unlock(&s->extralist.lock); return node; } @@ -164,15 +169,18 @@ ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s) orig_cpu = cpu = raw_smp_processor_id(); while (1) { head = per_cpu_ptr(s->freelist, cpu); + if (!READ_ONCE(head->first)) + goto next_cpu; if (raw_spin_trylock(&head->lock)) { node = head->first; if (node) { - head->first = node->next; + WRITE_ONCE(head->first, node->next); raw_spin_unlock(&head->lock); return node; } raw_spin_unlock(&head->lock); } +next_cpu: cpu = cpumask_next(cpu, cpu_possible_mask); if (cpu >= nr_cpu_ids) cpu = 0; @@ -181,11 +189,11 @@ ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s) } /* cannot pop from per cpu lists, try extralist */ - if (!raw_spin_trylock(&s->extralist.lock)) + if (!READ_ONCE(s->extralist.first) || !raw_spin_trylock(&s->extralist.lock)) return NULL; node = s->extralist.first; if (node) - s->extralist.first = node->next; + WRITE_ONCE(s->extralist.first, node->next); raw_spin_unlock(&s->extralist.lock); return node; } |