From 3aac1ead5eb6b76f3d2b8d111e6de1c2de23fb34 Mon Sep 17 00:00:00 2001
From: Toke Høiland-Jørgensen <toke@redhat.com>
Date: Tue, 29 Sep 2020 14:45:50 +0200
Subject: bpf: Move prog->aux->linked_prog and trampoline into bpf_link on
attach
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In preparation for allowing multiple attachments of freplace programs, move
the references to the target program and trampoline into the
bpf_tracing_link structure when that is created. To do this atomically,
introduce a new mutex in prog->aux to protect writing to the two pointers
to target prog and trampoline, and rename the members to make it clear that
they are related.
With this change, it is no longer possible to attach the same tracing
program multiple times (detaching in-between), since the reference from the
tracing program to the target disappears on the first attach. However,
since the next patch will let the caller supply an attach target, that will
also make it possible to attach to the same place multiple times.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/160138355059.48470.2503076992210324984.stgit@toke.dk
---
kernel/bpf/preload/iterators/iterators.bpf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
(limited to 'kernel/bpf/preload/iterators/iterators.bpf.c')
diff --git a/kernel/bpf/preload/iterators/iterators.bpf.c b/kernel/bpf/preload/iterators/iterators.bpf.c
index 5ded550b2ed6..52aa7b38e8b8 100644
--- a/kernel/bpf/preload/iterators/iterators.bpf.c
+++ b/kernel/bpf/preload/iterators/iterators.bpf.c
@@ -42,7 +42,7 @@ struct bpf_prog_aux {
__u32 id;
char name[16];
const char *attach_func_name;
- struct bpf_prog *linked_prog;
+ struct bpf_prog *dst_prog;
struct bpf_func_info *func_info;
struct btf *btf;
};
@@ -108,7 +108,7 @@ int dump_bpf_prog(struct bpf_iter__bpf_prog *ctx)
BPF_SEQ_PRINTF(seq, "%4u %-16s %s %s\n", aux->id,
get_name(aux->btf, aux->func_info[0].type_id, aux->name),
- aux->attach_func_name, aux->linked_prog->aux->name);
+ aux->attach_func_name, aux->dst_prog->aux->name);
return 0;
}
char LICENSE[] SEC("license") = "GPL";
--
cgit