[PATCH 12/19] bpf: Add bpf_trampoline_alloc function

Jiri Olsa
2021-06-05T11:11:24Z

Factor out the bpf_trampoline_alloc function. It will
be used to allocate trampoline for multi-func programs
in following patches.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/trampoline.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 28a3630c48ee..2755fdcf9fbf 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -58,11 +58,27 @@ void bpf_image_ksym_del(struct bpf_ksym *ksym)
PAGE_SIZE, true, ksym->name);
}

+static struct bpf_trampoline *bpf_trampoline_alloc(void)
+{
+ struct bpf_trampoline *tr;
+ int i;
+
+ tr = kzalloc(sizeof(*tr), GFP_KERNEL);
+ if (!tr)
+ return NULL;
+
+ INIT_HLIST_NODE(&tr->hlist);
+ refcount_set(&tr->refcnt, 1);
+ mutex_init(&tr->mutex);
+ for (i = 0; i < BPF_TRAMP_MAX; i++)
+ INIT_HLIST_HEAD(&tr->progs_hlist[i]);
+ return tr;
+}
+
static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
{
struct bpf_trampoline *tr;
struct hlist_head *head;
- int i;

mutex_lock(&trampoline_mutex);
head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)];
@@ -72,17 +88,11 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
goto out;
}
}
- tr = kzalloc(sizeof(*tr), GFP_KERNEL);
- if (!tr)
- goto out;
-
- tr->key = key;
- INIT_HLIST_NODE(&tr->hlist);
- hlist_add_head(&tr->hlist, head);
- refcount_set(&tr->refcnt, 1);
- mutex_init(&tr->mutex);
- for (i = 0; i < BPF_TRAMP_MAX; i++)
- INIT_HLIST_HEAD(&tr->progs_hlist[i]);
+ tr = bpf_trampoline_alloc();
+ if (tr) {
+ tr->key = key;
+ hlist_add_head(&tr->hlist, head);
+ }
out:
mutex_unlock(&trampoline_mutex);
return tr;
--
2.31.1