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Message-Id: <20220601190218.2494963-2-sdf@google.com>
Date: Wed, 1 Jun 2022 12:02:08 -0700
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
Stanislav Fomichev <sdf@...gle.com>
Subject: [PATCH bpf-next v8 01/11] bpf: add bpf_func_t and trampoline helpers
I'll be adding lsm cgroup specific helpers that grab
trampoline mutex.
No functional changes.
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
include/linux/bpf.h | 11 ++++---
kernel/bpf/trampoline.c | 63 +++++++++++++++++++++--------------------
2 files changed, 38 insertions(+), 36 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 8e6092d0ea95..b0af68b6297b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -53,6 +53,8 @@ typedef u64 (*bpf_callback_t)(u64, u64, u64, u64, u64);
typedef int (*bpf_iter_init_seq_priv_t)(void *private_data,
struct bpf_iter_aux_info *aux);
typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data);
+typedef unsigned int (*bpf_func_t)(const void *,
+ const struct bpf_insn *);
struct bpf_iter_seq_info {
const struct seq_operations *seq_ops;
bpf_iter_init_seq_priv_t init_seq_private;
@@ -863,8 +865,7 @@ struct bpf_dispatcher {
static __always_inline __nocfi unsigned int bpf_dispatcher_nop_func(
const void *ctx,
const struct bpf_insn *insnsi,
- unsigned int (*bpf_func)(const void *,
- const struct bpf_insn *))
+ bpf_func_t bpf_func)
{
return bpf_func(ctx, insnsi);
}
@@ -893,8 +894,7 @@ int arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs);
noinline __nocfi unsigned int bpf_dispatcher_##name##_func( \
const void *ctx, \
const struct bpf_insn *insnsi, \
- unsigned int (*bpf_func)(const void *, \
- const struct bpf_insn *)) \
+ bpf_func_t bpf_func) \
{ \
return bpf_func(ctx, insnsi); \
} \
@@ -905,8 +905,7 @@ int arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs);
unsigned int bpf_dispatcher_##name##_func( \
const void *ctx, \
const struct bpf_insn *insnsi, \
- unsigned int (*bpf_func)(const void *, \
- const struct bpf_insn *)); \
+ bpf_func_t bpf_func); \
extern struct bpf_dispatcher bpf_dispatcher_##name;
#define BPF_DISPATCHER_FUNC(name) bpf_dispatcher_##name##_func
#define BPF_DISPATCHER_PTR(name) (&bpf_dispatcher_##name)
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 93c7675f0c9e..5466e15be61f 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -410,7 +410,7 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog)
}
}
-int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+static int __bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
struct bpf_tramp_link *link_exiting;
@@ -418,44 +418,33 @@ int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline
int cnt = 0, i;
kind = bpf_attach_type_to_tramp(link->link.prog);
- mutex_lock(&tr->mutex);
- if (tr->extension_prog) {
+ if (tr->extension_prog)
/* cannot attach fentry/fexit if extension prog is attached.
* cannot overwrite extension prog either.
*/
- err = -EBUSY;
- goto out;
- }
+ return -EBUSY;
for (i = 0; i < BPF_TRAMP_MAX; i++)
cnt += tr->progs_cnt[i];
if (kind == BPF_TRAMP_REPLACE) {
/* Cannot attach extension if fentry/fexit are in use. */
- if (cnt) {
- err = -EBUSY;
- goto out;
- }
+ if (cnt)
+ return -EBUSY;
tr->extension_prog = link->link.prog;
- err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
- link->link.prog->bpf_func);
- goto out;
- }
- if (cnt >= BPF_MAX_TRAMP_LINKS) {
- err = -E2BIG;
- goto out;
+ return bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
+ link->link.prog->bpf_func);
}
- if (!hlist_unhashed(&link->tramp_hlist)) {
+ if (cnt >= BPF_MAX_TRAMP_LINKS)
+ return -E2BIG;
+ if (!hlist_unhashed(&link->tramp_hlist))
/* prog already linked */
- err = -EBUSY;
- goto out;
- }
+ return -EBUSY;
hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) {
if (link_exiting->link.prog != link->link.prog)
continue;
/* prog already linked */
- err = -EBUSY;
- goto out;
+ return -EBUSY;
}
hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]);
@@ -465,30 +454,44 @@ int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline
hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
}
-out:
+ return err;
+}
+
+int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+ int err;
+
+ mutex_lock(&tr->mutex);
+ err = __bpf_trampoline_link_prog(link, tr);
mutex_unlock(&tr->mutex);
return err;
}
-/* bpf_trampoline_unlink_prog() should never fail. */
-int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+static int __bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
int err;
kind = bpf_attach_type_to_tramp(link->link.prog);
- mutex_lock(&tr->mutex);
if (kind == BPF_TRAMP_REPLACE) {
WARN_ON_ONCE(!tr->extension_prog);
err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP,
tr->extension_prog->bpf_func, NULL);
tr->extension_prog = NULL;
- goto out;
+ return err;
}
hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
- err = bpf_trampoline_update(tr);
-out:
+ return bpf_trampoline_update(tr);
+}
+
+/* bpf_trampoline_unlink_prog() should never fail. */
+int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+ int err;
+
+ mutex_lock(&tr->mutex);
+ err = __bpf_trampoline_unlink_prog(link, tr);
mutex_unlock(&tr->mutex);
return err;
}
--
2.36.1.255.ge46751e96f-goog
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