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From: Stanislav Fomichev <sdf@google.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	Stanislav Fomichev <sdf@google.com>,
	Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf-next v10 01/11] bpf: add bpf_func_t and trampoline helpers
Date: Wed, 22 Jun 2022 09:03:36 -0700	[thread overview]
Message-ID: <20220622160346.967594-2-sdf@google.com> (raw)
In-Reply-To: <20220622160346.967594-1-sdf@google.com>

I'll be adding lsm cgroup specific helpers that grab
trampoline mutex.

No functional changes.

Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.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 d05e1495a06e..d547be9db75f 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -56,6 +56,8 @@ 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;
@@ -879,8 +881,7 @@ 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);
 }
@@ -909,8 +910,7 @@ 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);				\
 	}								\
@@ -921,8 +921,7 @@ 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;
 }
-- 
2.37.0.rc0.104.g0611611a94-goog


  reply	other threads:[~2022-06-22 16:03 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-22 16:03 [PATCH bpf-next v10 00/11] bpf: cgroup_sock lsm flavor Stanislav Fomichev
2022-06-22 16:03 ` Stanislav Fomichev [this message]
2022-06-22 16:03 ` [PATCH bpf-next v10 02/11] bpf: convert cgroup_bpf.progs to hlist Stanislav Fomichev
2022-06-22 16:03 ` [PATCH bpf-next v10 03/11] bpf: per-cgroup lsm flavor Stanislav Fomichev
2022-06-23 22:40   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 04/11] bpf: minimize number of allocated lsm slots per program Stanislav Fomichev
2022-06-23 22:41   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 05/11] bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP Stanislav Fomichev
2022-06-22 16:03 ` [PATCH bpf-next v10 06/11] bpf: expose bpf_{g,s}etsockopt to lsm cgroup Stanislav Fomichev
2022-06-23 22:43   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 07/11] tools/bpf: Sync btf_ids.h to tools Stanislav Fomichev
2022-06-23 22:54   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 08/11] libbpf: add lsm_cgoup_sock type Stanislav Fomichev
2022-06-23 22:54   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 09/11] libbpf: implement bpf_prog_query_opts Stanislav Fomichev
2022-06-23 22:58   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 10/11] bpftool: implement cgroup tree for BPF_LSM_CGROUP Stanislav Fomichev
2022-06-23 22:58   ` Martin KaFai Lau
2022-06-22 16:03 ` [PATCH bpf-next v10 11/11] selftests/bpf: lsm_cgroup functional test Stanislav Fomichev
2022-06-23 22:36   ` Martin KaFai Lau
2022-06-23 23:48     ` Stanislav Fomichev

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