Merge branch 'bpf_sk_storage_via_inet_diag'

Martin KaFai Lau says:

====================
The bpf_prog can store specific info to a sk by using bpf_sk_storage.
In other words, a sk can be extended by a bpf_prog.

This series is to support providing bpf_sk_storage data during inet_diag's
dump.  The primary target is the usage like iproute2's "ss".

The first two patches are refactoring works in inet_diag to make
adding bpf_sk_storage support easier.  The next two patches do
the actual work.

Please see individual patch for details.

v2:
- Add commit message for u16 to u32 change in min_dump_alloc in Patch 4 (Song)
- Add comment to explain the !skb->len check in __inet_diag_dump in Patch 4.
- Do the map->map_type check earlier in Patch 3 for readability.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a79743a89815..c536c65256ad 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -902,6 +902,21 @@ void bpf_map_inc_with_uref(struct bpf_map *map)
 }
 EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);
 
+struct bpf_map *bpf_map_get(u32 ufd)
+{
+	struct fd f = fdget(ufd);
+	struct bpf_map *map;
+
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return map;
+
+	bpf_map_inc(map);
+	fdput(f);
+
+	return map;
+}
+
 struct bpf_map *bpf_map_get_with_uref(u32 ufd)
 {
 	struct fd f = fdget(ufd);