Subject: [PATCH 09/18] bpf: Add bpf_ksym_add/del functions

From: Jiri Olsa <[email-masked]>
Date: Sun, 16 Feb 2020 20:29:56 +0100

Adding bpf_ksym_add/del functions as locked version
for __bpf_ksym_add/del. It will be used in following
patches for bpf_trampoline and bpf_dispatcher.

Signed-off-by: Jiri Olsa <[email-masked]>
---
 include/linux/bpf.h |  3 +++
 kernel/bpf/core.c   | 14 ++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 5d6649cdc3df..76934893bccf 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -573,6 +573,9 @@ struct bpf_image {
 #define BPF_IMAGE_SIZE (PAGE_SIZE - sizeof(struct bpf_image))
 bool is_bpf_image_address(unsigned long address);
 void *bpf_image_alloc(void);
+/* Called only from code, so there's no need for stubs. */
+void bpf_ksym_add(struct bpf_ksym *ksym);
+void bpf_ksym_del(struct bpf_ksym *ksym);
 #else
 static inline struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
 {
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index f361cfdf8d9e..739bef60d868 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -655,6 +655,13 @@ static void __bpf_ksym_add(struct bpf_ksym *ksym)
 	latch_tree_insert(&ksym->tnode, &bpf_ksym_tree, &bpf_ksym_tree_ops);
 }
 
+void bpf_ksym_add(struct bpf_ksym *ksym)
+{
+	spin_lock_bh(&bpf_lock);
+	__bpf_ksym_add(ksym);
+	spin_unlock_bh(&bpf_lock);
+}
+
 static void __bpf_ksym_del(struct bpf_ksym *ksym)
 {
 	if (list_empty(&ksym->lnode))
@@ -664,6 +671,13 @@ static void __bpf_ksym_del(struct bpf_ksym *ksym)
 	list_del_rcu(&ksym->lnode);
 }
 
+void bpf_ksym_del(struct bpf_ksym *ksym)
+{
+	spin_lock_bh(&bpf_lock);
+	__bpf_ksym_del(ksym);
+	spin_unlock_bh(&bpf_lock);
+}
+
 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
 {
 	return fp->jited && !bpf_prog_was_classic(fp);
-- 
2.24.1