[RFC PATCH bpf-next 04/12] bpf: Remove unnecessary prog_list_prog() check

[Martin KaFai Lau <martin.lau@linux.dev>]

From: Martin KaFai Lau <martin.lau@kernel.org>

Both replace_effective_prog() and purge_effective_progs() test
the "!prog_list_prog(pl)" to skip a 'detaching' pl.

When detaching a pl, pl->prog and pl->link are set to NULL in case
the update_effective_progs() failed.

However, replace_effective_prog() is not detaching a pl,
so the case "!prog_list_prog()" will not happen.

In purge_effective_prog(), the pl->prog and pl->link are restored
before calling purge_effective_progs(), so the case "!prog_list_prog()"
will not happen either.

This patch removes them as a prep work for the upcoming work
in attaching struct_ops to cgroup. When attaching a struct_ops
to cgroup, there is a link->map case and the prog_list_prog()
will not consider the link->map. The replace_effective_prog()
and purge_effective_progs() will then incorrectly skip a pl
with struct_ops map attached to it.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 kernel/bpf/cgroup.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 876f6a81a9b6..71591f6dc458 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -946,8 +946,6 @@ static void replace_effective_prog(struct cgroup *cgrp,
 
 			head = &cg->bpf.progs[atype];
 			hlist_for_each_entry(pl, head, node) {
-				if (!prog_list_prog(pl))
-					continue;
 				if (pl->link == link)
 					goto found;
 				pos++;
@@ -1099,8 +1097,6 @@ static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog,
 
 			head = &cg->bpf.progs[atype];
 			hlist_for_each_entry(pl, head, node) {
-				if (!prog_list_prog(pl))
-					continue;
 				if (pl->prog == prog && pl->link == link)
 					goto found;
 				pos++;
-- 
2.53.0-Meta