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bpf: split map modification structs
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@lmb @intel-lab-lkp
lmb authored and intel-lab-lkp committed Oct 14, 2021
1 parent 25064d1 commit 3b259b92970a70db700a73212711945e3ca0f9c2
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Showing 2 changed files with 70 additions and 51 deletions.
51 include/uapi/linux/bpf.h
View file
@@ -1294,18 +1294,41 @@ struct bpf_map_create_attr {
*/
};

struct bpf_map_lookup_elem_attr {
__u32 map_fd;
__bpf_md_ptr(const void *, key);
__bpf_md_ptr(void *, value);
__u64 flags;
};

struct bpf_map_update_elem_attr {
__u32 map_fd;
__bpf_md_ptr(const void *, key);
__bpf_md_ptr(void *, value);
__u64 flags;
};

struct bpf_map_delete_elem_attr {
__u32 map_fd;
__bpf_md_ptr(const void *, key);
};

struct bpf_map_get_next_key_attr {
__u32 map_fd;
__bpf_md_ptr(const void *, key);
__bpf_md_ptr(void *, next_key);
};

union bpf_attr {
struct bpf_map_create_attr map_create;

struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
__u32 map_fd;
__aligned_u64 key;
union {
__aligned_u64 value;
__aligned_u64 next_key;
};
__u64 flags;
};
struct bpf_map_lookup_elem_attr map_lookup_elem;

struct bpf_map_update_elem_attr map_update_elem;

struct bpf_map_delete_elem_attr map_delete_elem;

struct bpf_map_get_next_key_attr map_get_next_key;

struct { /* struct used by BPF_MAP_*_BATCH commands */
__aligned_u64 in_batch; /* start batch,
@@ -1524,6 +1547,16 @@ union bpf_attr {
__u32 btf_value_type_id;
__u32 btf_vmlinux_value_type_id;
};

struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
__u32 map_fd;
__aligned_u64 key;
union {
__aligned_u64 value;
__aligned_u64 next_key;
};
__u64 flags;
};
} __attribute__((aligned(8)));

/* The description below is an attempt at providing documentation to eBPF
70 kernel/bpf/syscall.c
View file
@@ -728,6 +728,11 @@ int bpf_get_file_flag(int flags)
__tmp; \
})

#define CHECK_ATTR_TAIL(attr, field) \
(memchr_inv((void *)(attr) + offsetofend(typeof(*attr), field), 0, \
sizeof(*(attr)) - offsetofend(typeof(*attr), field)) != NULL ? -EINVAL : 0)


/* dst and src must have at least "size" number of bytes.
* Return strlen on success and < 0 on error.
*/
@@ -1041,23 +1046,17 @@ static void *___bpf_copy_key(bpfptr_t ukey, u64 key_size)
return NULL;
}

/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags

static int map_lookup_elem(union bpf_attr *attr)
static int map_lookup_elem(struct bpf_map_lookup_elem_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *uvalue = u64_to_user_ptr(attr->value);
int ufd = attr->map_fd;
void __user *ukey = u64_to_user_ptr(attr->key_u64);
void __user *uvalue = u64_to_user_ptr(attr->value_u64);
int ufd = attr->fd;
struct bpf_map *map;
void *key, *value;
u32 value_size;
struct fd f;
int err;

if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM))
return -EINVAL;

if (attr->flags & ~BPF_F_LOCK)
return -EINVAL;

@@ -1108,23 +1107,17 @@ static int map_lookup_elem(union bpf_attr *attr)
return err;
}


#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags

static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
static int map_update_elem(struct bpf_map_update_elem_attr *attr, bpfptr_t uattr)
{
bpfptr_t ukey = make_bpfptr(attr->key, uattr.is_kernel);
bpfptr_t uvalue = make_bpfptr(attr->value, uattr.is_kernel);
int ufd = attr->map_fd;
bpfptr_t ukey = make_bpfptr(attr->key_u64, uattr.is_kernel);
bpfptr_t uvalue = make_bpfptr(attr->value_u64, uattr.is_kernel);
int ufd = attr->fd;
struct bpf_map *map;
void *key, *value;
u32 value_size;
struct fd f;
int err;

if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM))
return -EINVAL;

f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
@@ -1168,20 +1161,15 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
return err;
}

#define BPF_MAP_DELETE_ELEM_LAST_FIELD key

static int map_delete_elem(union bpf_attr *attr)
static int map_delete_elem(struct bpf_map_delete_elem_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
int ufd = attr->map_fd;
void __user *ukey = u64_to_user_ptr(attr->key_u64);
int ufd = attr->fd;
struct bpf_map *map;
struct fd f;
void *key;
int err;

if (CHECK_ATTR(BPF_MAP_DELETE_ELEM))
return -EINVAL;

f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
@@ -1220,22 +1208,16 @@ static int map_delete_elem(union bpf_attr *attr)
return err;
}

/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key

static int map_get_next_key(union bpf_attr *attr)
static int map_get_next_key(struct bpf_map_get_next_key_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *unext_key = u64_to_user_ptr(attr->next_key);
int ufd = attr->map_fd;
void __user *ukey = u64_to_user_ptr(attr->key_u64);
void __user *unext_key = u64_to_user_ptr(attr->next_key_u64);
int ufd = attr->fd;
struct bpf_map *map;
void *key, *next_key;
struct fd f;
int err;

if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY))
return -EINVAL;

f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
@@ -4578,16 +4560,20 @@ static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
err = map_create(ATTR_FIELD(&attr, map_create));
break;
case BPF_MAP_LOOKUP_ELEM:
err = map_lookup_elem(&attr);
err = CHECK_ATTR_TAIL(&attr, map_lookup_elem);
err = err ?: map_lookup_elem(&attr.map_lookup_elem);
break;
case BPF_MAP_UPDATE_ELEM:
err = map_update_elem(&attr, uattr);
err = CHECK_ATTR_TAIL(&attr, map_update_elem);
err = err ?: map_update_elem(&attr.map_update_elem, uattr);
break;
case BPF_MAP_DELETE_ELEM:
err = map_delete_elem(&attr);
err = CHECK_ATTR_TAIL(&attr, map_delete_elem);
err = err ?: map_delete_elem(&attr.map_delete_elem);
break;
case BPF_MAP_GET_NEXT_KEY:
err = map_get_next_key(&attr);
err = CHECK_ATTR_TAIL(&attr, map_get_next_key);
err = err ?: map_get_next_key(&attr.map_get_next_key);
break;
case BPF_MAP_FREEZE:
err = map_freeze(&attr);

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