1 files changed, 49 insertions, 14 deletions

diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index f9274114c88d..fed15cf94dca 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -718,21 +718,12 @@ static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab)
 	       BITS_PER_LONG == 64;
 }
 
-static u32 htab_size_value(const struct bpf_htab *htab, bool percpu)
-{
-	u32 size = htab->map.value_size;
-
-	if (percpu || fd_htab_map_needs_adjust(htab))
-		size = round_up(size, 8);
-	return size;
-}
-
 static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 					 void *value, u32 key_size, u32 hash,
 					 bool percpu, bool onallcpus,
 					 struct htab_elem *old_elem)
 {
-	u32 size = htab_size_value(htab, percpu);
+	u32 size = htab->map.value_size;
 	bool prealloc = htab_is_prealloc(htab);
 	struct htab_elem *l_new, **pl_new;
 	void __percpu *pptr;
@@ -770,10 +761,13 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 			l_new = ERR_PTR(-ENOMEM);
 			goto dec_count;
 		}
+		check_and_init_map_lock(&htab->map,
+					l_new->key + round_up(key_size, 8));
 	}
 
 	memcpy(l_new->key, key, key_size);
 	if (percpu) {
+		size = round_up(size, 8);
 		if (prealloc) {
 			pptr = htab_elem_get_ptr(l_new, key_size);
 		} else {
@@ -791,8 +785,13 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
 
 		if (!prealloc)
 			htab_elem_set_ptr(l_new, key_size, pptr);
-	} else {
+	} else if (fd_htab_map_needs_adjust(htab)) {
+		size = round_up(size, 8);
 		memcpy(l_new->key + round_up(key_size, 8), value, size);
+	} else {
+		copy_map_value(&htab->map,
+			       l_new->key + round_up(key_size, 8),
+			       value);
 	}
 
 	l_new->hash = hash;
@@ -805,11 +804,11 @@ dec_count:
 static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
 		       u64 map_flags)
 {
-	if (l_old && map_flags == BPF_NOEXIST)
+	if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST)
 		/* elem already exists */
 		return -EEXIST;
 
-	if (!l_old && map_flags == BPF_EXIST)
+	if (!l_old && (map_flags & ~BPF_F_LOCK) == BPF_EXIST)
 		/* elem doesn't exist, cannot update it */
 		return -ENOENT;
 
@@ -828,7 +827,7 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 	u32 key_size, hash;
 	int ret;
 
-	if (unlikely(map_flags > BPF_EXIST))
+	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
 		/* unknown flags */
 		return -EINVAL;
 
@@ -841,6 +840,28 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 	b = __select_bucket(htab, hash);
 	head = &b->head;
 
+	if (unlikely(map_flags & BPF_F_LOCK)) {
+		if (unlikely(!map_value_has_spin_lock(map)))
+			return -EINVAL;
+		/* find an element without taking the bucket lock */
+		l_old = lookup_nulls_elem_raw(head, hash, key, key_size,
+					      htab->n_buckets);
+		ret = check_flags(htab, l_old, map_flags);
+		if (ret)
+			return ret;
+		if (l_old) {
+			/* grab the element lock and update value in place */
+			copy_map_value_locked(map,
+					      l_old->key + round_up(key_size, 8),
+					      value, false);
+			return 0;
+		}
+		/* fall through, grab the bucket lock and lookup again.
+		 * 99.9% chance that the element won't be found,
+		 * but second lookup under lock has to be done.
+		 */
+	}
+
 	/* bpf_map_update_elem() can be called in_irq() */
 	raw_spin_lock_irqsave(&b->lock, flags);
 
@@ -850,6 +871,20 @@ static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
 	if (ret)
 		goto err;
 
+	if (unlikely(l_old && (map_flags & BPF_F_LOCK))) {
+		/* first lookup without the bucket lock didn't find the element,
+		 * but second lookup with the bucket lock found it.
+		 * This case is highly unlikely, but has to be dealt with:
+		 * grab the element lock in addition to the bucket lock
+		 * and update element in place
+		 */
+		copy_map_value_locked(map,
+				      l_old->key + round_up(key_size, 8),
+				      value, false);
+		ret = 0;
+		goto err;
+	}
+
 	l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false,
 				l_old);
 	if (IS_ERR(l_new)) {