From 59d3656d5bf504f771fc44fdbc7a9a8590795f22 Mon Sep 17 00:00:00 2001
From: Brenden Blanco <bblanco@plumgrid.com>
Date: Tue, 19 Jul 2016 12:16:46 -0700
Subject: [PATCH] bpf: add bpf_prog_add api for bulk prog refcnt
A subsystem may need to store many copies of a bpf program, each
deserving its own reference. Rather than requiring the caller to loop
one by one (with possible mid-loop failure), add a bulk bpf_prog_add
api.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 12 +++++++++---
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c13e92b00bf58..75a5ae6bee074 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -224,6 +224,7 @@ void bpf_register_map_type(struct bpf_map_type_list *tl);
struct bpf_prog *bpf_prog_get(u32 ufd);
struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
+struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i);
struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
void bpf_prog_put(struct bpf_prog *prog);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 96d938a220501..228f962447a50 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -670,14 +670,20 @@ static struct bpf_prog *____bpf_prog_get(struct fd f)
return f.file->private_data;
}
-struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
+struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
{
- if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) {
- atomic_dec(&prog->aux->refcnt);
+ if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {
+ atomic_sub(i, &prog->aux->refcnt);
return ERR_PTR(-EBUSY);
}
return prog;
}
+EXPORT_SYMBOL_GPL(bpf_prog_add);
+
+struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
+{
+ return bpf_prog_add(prog, 1);
+}
static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type)
{
--
2.30.2