From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 24 Feb 2020 15:01:50 +0100
Subject: bpf: Factor out hashtab bucket lock operations
Patch-mainline: v5.7-rc1
Git-commit: d01f9b198ca985b49717d8cd0b1f57806cb1319a
References: bsc#1177028
As a preparation for making the BPF locking RT friendly, factor out the
hash bucket lock operations into inline functions. This allows to do the
necessary RT modification in one place instead of sprinkling it all over
the place. No functional change.
The now unused htab argument of the lock/unlock functions will be used in
the next step which adds PREEMPT_RT support.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145644.420416916@linutronix.de
Acked-by: Gary Lin <glin@suse.com>
---
kernel/bpf/hashtab.c | 69 ++++++++++++++++++++++++++++++++++-----------------
1 file changed, 46 insertions(+), 23 deletions(-)
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -88,6 +88,32 @@ struct htab_elem {
char key[0] __aligned(8);
};
+static void htab_init_buckets(struct bpf_htab *htab)
+{
+ unsigned i;
+
+ for (i = 0; i < htab->n_buckets; i++) {
+ INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
+ raw_spin_lock_init(&htab->buckets[i].lock);
+ }
+}
+
+static inline unsigned long htab_lock_bucket(const struct bpf_htab *htab,
+ struct bucket *b)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&b->lock, flags);
+ return flags;
+}
+
+static inline void htab_unlock_bucket(const struct bpf_htab *htab,
+ struct bucket *b,
+ unsigned long flags)
+{
+ raw_spin_unlock_irqrestore(&b->lock, flags);
+}
+
static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
static bool htab_is_lru(const struct bpf_htab *htab)
@@ -348,8 +374,8 @@ static struct bpf_map *htab_map_alloc(un
bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
struct bpf_htab *htab;
- int err, i;
u64 cost;
+ int err;
htab = kzalloc(sizeof(*htab), GFP_USER);
if (!htab)
@@ -411,10 +437,7 @@ static struct bpf_map *htab_map_alloc(un
else
htab->hashrnd = get_random_int();
- for (i = 0; i < htab->n_buckets; i++) {
- INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
- raw_spin_lock_init(&htab->buckets[i].lock);
- }
+ htab_init_buckets(htab);
if (prealloc) {
err = prealloc_init(htab);
@@ -622,7 +645,7 @@ static bool htab_lru_map_delete_node(voi
b = __select_bucket(htab, tgt_l->hash);
head = &b->head;
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
if (l == tgt_l) {
@@ -630,7 +653,7 @@ static bool htab_lru_map_delete_node(voi
break;
}
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
return l == tgt_l;
}
@@ -896,7 +919,7 @@ static int htab_map_update_elem(struct b
*/
}
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l_old = lookup_elem_raw(head, hash, key, key_size);
@@ -937,7 +960,7 @@ static int htab_map_update_elem(struct b
}
ret = 0;
err:
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
return ret;
}
@@ -975,7 +998,7 @@ static int htab_lru_map_update_elem(stru
return -ENOMEM;
memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size);
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l_old = lookup_elem_raw(head, hash, key, key_size);
@@ -994,7 +1017,7 @@ static int htab_lru_map_update_elem(stru
ret = 0;
err:
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
if (ret)
bpf_lru_push_free(&htab->lru, &l_new->lru_node);
@@ -1029,7 +1052,7 @@ static int __htab_percpu_map_update_elem
b = __select_bucket(htab, hash);
head = &b->head;
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l_old = lookup_elem_raw(head, hash, key, key_size);
@@ -1052,7 +1075,7 @@ static int __htab_percpu_map_update_elem
}
ret = 0;
err:
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
return ret;
}
@@ -1092,7 +1115,7 @@ static int __htab_lru_percpu_map_update_
return -ENOMEM;
}
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l_old = lookup_elem_raw(head, hash, key, key_size);
@@ -1114,7 +1137,7 @@ static int __htab_lru_percpu_map_update_
}
ret = 0;
err:
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
if (l_new)
bpf_lru_push_free(&htab->lru, &l_new->lru_node);
return ret;
@@ -1152,7 +1175,7 @@ static int htab_map_delete_elem(struct b
b = __select_bucket(htab, hash);
head = &b->head;
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l = lookup_elem_raw(head, hash, key, key_size);
@@ -1162,7 +1185,7 @@ static int htab_map_delete_elem(struct b
ret = 0;
}
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
return ret;
}
@@ -1184,7 +1207,7 @@ static int htab_lru_map_delete_elem(stru
b = __select_bucket(htab, hash);
head = &b->head;
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
l = lookup_elem_raw(head, hash, key, key_size);
@@ -1193,7 +1216,7 @@ static int htab_lru_map_delete_elem(stru
ret = 0;
}
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
if (l)
bpf_lru_push_free(&htab->lru, &l->lru_node);
return ret;
@@ -1342,7 +1365,7 @@ again_nocopy:
head = &b->head;
/* do not grab the lock unless need it (bucket_cnt > 0). */
if (locked)
- raw_spin_lock_irqsave(&b->lock, flags);
+ flags = htab_lock_bucket(htab, b);
bucket_cnt = 0;
hlist_nulls_for_each_entry_rcu(l, n, head, hash_node)
@@ -1359,7 +1382,7 @@ again_nocopy:
/* Note that since bucket_cnt > 0 here, it is implicit
* that the locked was grabbed, so release it.
*/
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
rcu_read_unlock();
bpf_enable_instrumentation();
goto after_loop;
@@ -1370,7 +1393,7 @@ again_nocopy:
/* Note that since bucket_cnt > 0 here, it is implicit
* that the locked was grabbed, so release it.
*/
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
rcu_read_unlock();
bpf_enable_instrumentation();
kvfree(keys);
@@ -1423,7 +1446,7 @@ again_nocopy:
dst_val += value_size;
}
- raw_spin_unlock_irqrestore(&b->lock, flags);
+ htab_unlock_bucket(htab, b, flags);
locked = false;
while (node_to_free) {