[-next,3/5] bpf: Remove map_pop_elem callbacks with -EOPNOTSUPP

Commit Message

Xiaomeng Zhang Feb. 17, 2025, 1:41 a.m. UTC

Remove redundant map_pop_elem callbacks with return -EOPNOTSUPP. We can
directly return -EOPNOTSUPP when calling the unimplemented callbacks.

Signed-off-by: Xiaomeng Zhang <[e-mail]>
---
 kernel/bpf/arena.c        | 6 ------
 kernel/bpf/bloom_filter.c | 6 ------
 kernel/bpf/helpers.c      | 5 ++++-
 kernel/bpf/syscall.c      | 5 ++++-
 4 files changed, 8 insertions(+), 14 deletions(-)

Comments

Hou Tao Feb. 17, 2025, 2:31 a.m. UTC | #1

On 2/17/2025 9:41 AM, Xiaomeng Zhang wrote:
> Remove redundant map_pop_elem callbacks with return -EOPNOTSUPP. We can
> directly return -EOPNOTSUPP when calling the unimplemented callbacks.
>
> Signed-off-by: Xiaomeng Zhang <[e-mail]>
> ---
>  kernel/bpf/arena.c        | 6 ------
>  kernel/bpf/bloom_filter.c | 6 ------
>  kernel/bpf/helpers.c      | 5 ++++-
>  kernel/bpf/syscall.c      | 5 ++++-
>  4 files changed, 8 insertions(+), 14 deletions(-)
>

>  BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
>  {
> -	return map->ops->map_pop_elem(map, value);
> +	if (map->ops->map_pop_elem)
> +		return map->ops->map_pop_elem(map, value);
> +	else
> +		return -EOPNOTSUPP;
>  }
>  

Similar with the previous patch, it is unnecessary.
>  const struct bpf_func_proto bpf_map_pop_elem_proto = {
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 79a118ea9270..c6f55283f4ff 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2142,7 +2142,10 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr)
>  	err = -ENOTSUPP;
>  	if (map->map_type == BPF_MAP_TYPE_QUEUE ||
>  	    map->map_type == BPF_MAP_TYPE_STACK) {
> -		err = map->ops->map_pop_elem(map, value);
> +		if (map->ops->map_pop_elem)
> +			err = map->ops->map_pop_elem(map, value);
> +		else
> +			err = -EOPNOTSUPP;

It is also unnecessary.
>  	} else if (map->map_type == BPF_MAP_TYPE_HASH ||
>  		   map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
>  		   map->map_type == BPF_MAP_TYPE_LRU_HASH ||

Patch

diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 7ee98aeccf3c..2c95baa8ece2 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c
@@ -62,11 +62,6 @@  u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena)
 	return arena ? arena->user_vm_start : 0;
 }
 
-static long arena_map_pop_elem(struct bpf_map *map, void *value)
-{
-	return -EOPNOTSUPP;
-}
-
 static long arena_map_delete_elem(struct bpf_map *map, void *value)
 {
 	return -EOPNOTSUPP;
@@ -393,7 +388,6 @@  const struct bpf_map_ops arena_map_ops = {
 	.map_mmap = arena_map_mmap,
 	.map_get_unmapped_area = arena_get_unmapped_area,
 	.map_get_next_key = arena_map_get_next_key,
-	.map_pop_elem = arena_map_pop_elem,
 	.map_lookup_elem = arena_map_lookup_elem,
 	.map_update_elem = arena_map_update_elem,
 	.map_delete_elem = arena_map_delete_elem,
diff --git a/kernel/bpf/bloom_filter.c b/kernel/bpf/bloom_filter.c
index 35e1ddca74d2..d8d4dd7b711d 100644
--- a/kernel/bpf/bloom_filter.c
+++ b/kernel/bpf/bloom_filter.c
@@ -65,11 +65,6 @@  static long bloom_map_push_elem(struct bpf_map *map, void *value, u64 flags)
 	return 0;
 }
 
-static long bloom_map_pop_elem(struct bpf_map *map, void *value)
-{
-	return -EOPNOTSUPP;
-}
-
 static long bloom_map_delete_elem(struct bpf_map *map, void *value)
 {
 	return -EOPNOTSUPP;
@@ -209,7 +204,6 @@  const struct bpf_map_ops bloom_filter_map_ops = {
 	.map_get_next_key = bloom_map_get_next_key,
 	.map_push_elem = bloom_map_push_elem,
 	.map_peek_elem = bloom_map_peek_elem,
-	.map_pop_elem = bloom_map_pop_elem,
 	.map_lookup_elem = bloom_map_lookup_elem,
 	.map_update_elem = bloom_map_update_elem,
 	.map_delete_elem = bloom_map_delete_elem,
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 000409c8308a..cb61c06155c8 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -106,7 +106,10 @@  const struct bpf_func_proto bpf_map_push_elem_proto = {
 
 BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value)
 {
-	return map->ops->map_pop_elem(map, value);
+	if (map->ops->map_pop_elem)
+		return map->ops->map_pop_elem(map, value);
+	else
+		return -EOPNOTSUPP;
 }
 
 const struct bpf_func_proto bpf_map_pop_elem_proto = {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 79a118ea9270..c6f55283f4ff 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2142,7 +2142,10 @@  static int map_lookup_and_delete_elem(union bpf_attr *attr)
 	err = -ENOTSUPP;
 	if (map->map_type == BPF_MAP_TYPE_QUEUE ||
 	    map->map_type == BPF_MAP_TYPE_STACK) {
-		err = map->ops->map_pop_elem(map, value);
+		if (map->ops->map_pop_elem)
+			err = map->ops->map_pop_elem(map, value);
+		else
+			err = -EOPNOTSUPP;
 	} else if (map->map_type == BPF_MAP_TYPE_HASH ||
 		   map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
 		   map->map_type == BPF_MAP_TYPE_LRU_HASH ||