[bpf-next,v2,10/20] bpf: Introduce bpf_dynptr_user

Commit Message

Hou Tao Jan. 25, 2025, 11:10 a.m. UTC

From: Hou Tao <[e-mail]>

For bpf map with dynptr key support, the userspace application will use
bpf_dynptr_user to represent the bpf_dynptr in the map key and pass it
to bpf syscall. The bpf syscall will copy from bpf_dynptr_user to
construct a corresponding bpf_dynptr_kern object when the map key is an
input argument, and copy to bpf_dynptr_user from a bpf_dynptr_kern
object when the map key is an output argument.

For now the size of bpf_dynptr_user must be the same as bpf_dynptr, but
the last u32 field is not used, so make it a reserved field.

Signed-off-by: Hou Tao <[e-mail]>
---
 include/uapi/linux/bpf.h       | 6 ++++++
 tools/include/uapi/linux/bpf.h | 6 ++++++
 2 files changed, 12 insertions(+)

Patch

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 2acf9b3363717..7d96685513c55 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7335,6 +7335,12 @@  struct bpf_dynptr {
 	__u64 __opaque[2];
 } __attribute__((aligned(8)));
 
+struct bpf_dynptr_user {
+	__bpf_md_ptr(void *, data);
+	__u32 size;
+	__u32 reserved;
+} __attribute__((aligned(8)));
+
 struct bpf_list_head {
 	__u64 __opaque[2];
 } __attribute__((aligned(8)));
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 2acf9b3363717..7d96685513c55 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7335,6 +7335,12 @@  struct bpf_dynptr {
 	__u64 __opaque[2];
 } __attribute__((aligned(8)));
 
+struct bpf_dynptr_user {
+	__bpf_md_ptr(void *, data);
+	__u32 size;
+	__u32 reserved;
+} __attribute__((aligned(8)));
+
 struct bpf_list_head {
 	__u64 __opaque[2];
 } __attribute__((aligned(8)));