This allows kernel code dealing with dynptrs obtain dynptr's available
size and current (w. proper offset) data pointer.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@xxxxxxxxx>
---
v5:
- fix bpf_dynptr_get_data's incorrect usage of bpf_dynptr_kern's size
spotted by Joanne Koong <joannelkoong@xxxxxxxxx>
v6:
- Simplify bpf_dynptr_get_data's interface and make it inline
suggested by John Fastabend <john.fastabend@xxxxxxxxx>
---
include/linux/bpf.h | 6 ++++++
kernel/bpf/helpers.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 48ae05099f36..e0844f45022f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2631,6 +2631,12 @@ 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);
+
+static inline void *bpf_dynptr_get_data(struct bpf_dynptr_kern *ptr)
+{
+ return ptr->data ? ptr->data + ptr->offset : NULL;
+}
#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 fc08035f14ed..824864ac82d1 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1408,7 +1408,7 @@ static void bpf_dynptr_set_type(struct bpf_dynptr_kern *ptr, enum bpf_dynptr_typ
ptr->size |= type << DYNPTR_TYPE_SHIFT;
}
-static u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
+u32 bpf_dynptr_get_size(struct bpf_dynptr_kern *ptr)
{
return ptr->size & DYNPTR_SIZE_MASK;
}
--
2.37.3
