From: Hou Tao <houtao1@xxxxxxxxxx>
For map with bpf_dynptr-typed key, lookup and update procedures will use
bpf_dynptr_get_size() to get the length of key, and iteration procedure
will use bpf_dynptr_set_size() to set the length of returned key.
The implementation of bpf_dynptr_set_size() is taken from Joanne's patch
"bpf: Add bpf_dynptr_trim and bpf_dynptr_advance". Also add a const
qualifier to dynptr argument of bpf_dynptr_get_size().
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
include/linux/bpf.h | 3 ++-
kernel/bpf/helpers.c | 9 ++++++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index edd43edb27d6..66a18dc67b46 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2660,7 +2660,8 @@ void bpf_dynptr_init(struct bpf_dynptr_kern *ptr, void *data,
enum bpf_dynptr_type type, u32 offset, u32 size);
void bpf_dynptr_set_null(struct bpf_dynptr_kern *ptr);
int bpf_dynptr_check_size(u32 size);
-u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr);
+u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr);
+void bpf_dynptr_set_size(struct bpf_dynptr_kern *ptr, u32 new_size);
#ifdef CONFIG_BPF_LSM
void bpf_cgroup_atype_get(u32 attach_btf_id, int cgroup_atype);
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index b069517a3da0..a9ca2de8f8cd 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1408,11 +1408,18 @@ static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_typ
ptr->size |= type << DYNPTR_TYPE_SHIFT;
}
-u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
+u32 bpf_dynptr_get_size(const struct bpf_dynptr_kern *ptr)
{
return ptr->size & DYNPTR_SIZE_MASK;
}
+void bpf_dynptr_set_size(struct bpf_dynptr_kern *ptr, u32 new_size)
+{
+ u32 metadata = ptr->size & ~DYNPTR_SIZE_MASK;
+
+ ptr->size = new_size | metadata;
+}
+
int bpf_dynptr_check_size(u32 size)
{
return size > DYNPTR_MAX_SIZE ? -E2BIG : 0;
--
2.29.2
