DEFINE_BPF_STORAGE_CACHE(task_cache);
+DEFINE_PER_CPU(int, bpf_task_storage_busy);
+
+static void bpf_task_storage_lock(void)
+{
+ migrate_disable();
+ __this_cpu_inc(bpf_task_storage_busy);
+}
+
+static void bpf_task_storage_unlock(void)
+{
+ __this_cpu_dec(bpf_task_storage_busy);
+ migrate_enable();
+}
+
+static bool bpf_task_storage_trylock(void)
+{
+ migrate_disable();
+ if (unlikely(__this_cpu_inc_return(bpf_task_storage_busy) != 1)) {
+ __this_cpu_dec(bpf_task_storage_busy);
+ migrate_enable();
+ return false;
+ }
+ return true;
+}
+
static struct bpf_local_storage __rcu **task_storage_ptr(void *owner)
{
struct task_struct *task = owner;
* when unlinking elem from the local_storage->list and
* the map's bucket->list.
*/
+ bpf_task_storage_lock();
raw_spin_lock_irqsave(&local_storage->lock, flags);
hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
/* Always unlink from map before unlinking from
local_storage, selem, false);
}
raw_spin_unlock_irqrestore(&local_storage->lock, flags);
+ bpf_task_storage_unlock();
rcu_read_unlock();
/* free_task_storage should always be true as long as
goto out;
}
+ bpf_task_storage_lock();
sdata = task_storage_lookup(task, map, true);
+ bpf_task_storage_unlock();
put_pid(pid);
return sdata ? sdata->data : NULL;
out:
goto out;
}
+ bpf_task_storage_lock();
sdata = bpf_local_storage_update(
task, (struct bpf_local_storage_map *)map, value, map_flags);
+ bpf_task_storage_unlock();
err = PTR_ERR_OR_ZERO(sdata);
out:
goto out;
}
+ bpf_task_storage_lock();
err = task_storage_delete(task, map);
+ bpf_task_storage_unlock();
out:
put_pid(pid);
return err;
if (!task)
return (unsigned long)NULL;
+ if (!bpf_task_storage_trylock())
+ return (unsigned long)NULL;
+
sdata = task_storage_lookup(task, map, true);
if (sdata)
- return (unsigned long)sdata->data;
+ goto unlock;
/* only allocate new storage, when the task is refcounted */
if (refcount_read(&task->usage) &&
- (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) {
+ (flags & BPF_LOCAL_STORAGE_GET_F_CREATE))
sdata = bpf_local_storage_update(
task, (struct bpf_local_storage_map *)map, value,
BPF_NOEXIST);
- return IS_ERR(sdata) ? (unsigned long)NULL :
- (unsigned long)sdata->data;
- }
- return (unsigned long)NULL;
+unlock:
+ bpf_task_storage_unlock();
+ return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL :
+ (unsigned long)sdata->data;
}
BPF_CALL_2(bpf_task_storage_delete, struct bpf_map *, map, struct task_struct *,
task)
{
+ int ret;
+
if (!task)
return -EINVAL;
+ if (!bpf_task_storage_trylock())
+ return -EBUSY;
+
/* This helper must only be called from places where the lifetime of the task
* is guaranteed. Either by being refcounted or by being protected
* by an RCU read-side critical section.
*/
- return task_storage_delete(task, map);
+ ret = task_storage_delete(task, map);
+ bpf_task_storage_unlock();
+ return ret;
}
static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key)
smap = (struct bpf_local_storage_map *)map;
bpf_local_storage_cache_idx_free(&task_cache, smap->cache_idx);
- bpf_local_storage_map_free(smap);
+ bpf_local_storage_map_free(smap, &bpf_task_storage_busy);
}
static int task_storage_map_btf_id;