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Message-Id: <20171220041006.25629-4-jakub.kicinski@netronome.com>
Date: Tue, 19 Dec 2017 20:10:01 -0800
From: Jakub Kicinski <jakub.kicinski@...ronome.com>
To: netdev@...r.kernel.org, alexei.starovoitov@...il.com,
daniel@...earbox.net
Cc: ktkhai@...tuozzo.com, oss-drivers@...ronome.com,
Jakub Kicinski <jakub.kicinski@...ronome.com>
Subject: [PATCH bpf-next 3/8] bpf: offload: allow netdev to disappear while verifier is running
To allow verifier instruction callbacks without any extra locking
NETDEV_UNREGISTER notification would wait on a waitqueue for verifier
to finish. This design decision was made when rtnl lock was providing
all the locking. Use the read/write lock instead and remove the
workqueue.
Verifier will now call into the offload code, so dev_ops are moved
to offload structure. Since verifier calls are all under
bpf_prog_is_dev_bound() we no longer need static inline implementations
to please builds with CONFIG_NET=n.
Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@...ronome.com>
Acked-by: Alexei Starovoitov <ast@...nel.org>
---
drivers/net/ethernet/netronome/nfp/bpf/main.h | 2 +-
drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 2 +-
drivers/net/netdevsim/bpf.c | 2 +-
include/linux/bpf.h | 9 +++++--
include/linux/bpf_verifier.h | 16 ++----------
include/linux/netdevice.h | 4 +--
kernel/bpf/offload.c | 30 ++++++++++++-----------
kernel/bpf/verifier.c | 20 ++++++---------
8 files changed, 37 insertions(+), 48 deletions(-)
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index aae1be9ed056..89a9b6393882 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h
@@ -238,7 +238,7 @@ struct nfp_bpf_vnic {
int nfp_bpf_jit(struct nfp_prog *prog);
-extern const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops;
+extern const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops;
struct netdev_bpf;
struct nfp_app;
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
index 9c2608445bd8..d8870c2f11f3 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c
@@ -260,6 +260,6 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx)
return 0;
}
-const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops = {
+const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops = {
.insn_hook = nfp_verify_insn,
};
diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c
index c977fece64a3..e363658405ee 100644
--- a/drivers/net/netdevsim/bpf.c
+++ b/drivers/net/netdevsim/bpf.c
@@ -66,7 +66,7 @@ nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn)
return 0;
}
-static const struct bpf_ext_analyzer_ops nsim_bpf_analyzer_ops = {
+static const struct bpf_prog_offload_ops nsim_bpf_analyzer_ops = {
.insn_hook = nsim_bpf_verify_insn,
};
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 838eee10e979..669549f7e3e8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -17,6 +17,7 @@
#include <linux/numa.h>
#include <linux/wait.h>
+struct bpf_verifier_env;
struct perf_event;
struct bpf_prog;
struct bpf_map;
@@ -184,14 +185,18 @@ struct bpf_verifier_ops {
struct bpf_prog *prog, u32 *target_size);
};
+struct bpf_prog_offload_ops {
+ int (*insn_hook)(struct bpf_verifier_env *env,
+ int insn_idx, int prev_insn_idx);
+};
+
struct bpf_dev_offload {
struct bpf_prog *prog;
struct net_device *netdev;
void *dev_priv;
struct list_head offloads;
bool dev_state;
- bool verifier_running;
- wait_queue_head_t verifier_done;
+ const struct bpf_prog_offload_ops *dev_ops;
};
struct bpf_prog_aux {
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index aaac589e490c..02ede122d35b 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -166,12 +166,6 @@ static inline bool bpf_verifier_log_full(const struct bpf_verifer_log *log)
return log->len_used >= log->len_total - 1;
}
-struct bpf_verifier_env;
-struct bpf_ext_analyzer_ops {
- int (*insn_hook)(struct bpf_verifier_env *env,
- int insn_idx, int prev_insn_idx);
-};
-
#define BPF_MAX_SUBPROGS 256
/* single container for all structs
@@ -185,7 +179,6 @@ struct bpf_verifier_env {
bool strict_alignment; /* perform strict pointer alignment checks */
struct bpf_verifier_state *cur_state; /* current verifier state */
struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
- const struct bpf_ext_analyzer_ops *dev_ops; /* device analyzer ops */
struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
u32 used_map_cnt; /* number of used maps */
u32 id_gen; /* used to generate unique reg IDs */
@@ -205,13 +198,8 @@ static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env)
return cur->frame[cur->curframe]->regs;
}
-#if defined(CONFIG_NET) && defined(CONFIG_BPF_SYSCALL)
int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env);
-#else
-static inline int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)
-{
- return -EOPNOTSUPP;
-}
-#endif
+int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
+ int insn_idx, int prev_insn_idx);
#endif /* _LINUX_BPF_VERIFIER_H */
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index cc4ce7456e38..0a1a4a111546 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -804,7 +804,7 @@ enum bpf_netdev_command {
BPF_OFFLOAD_DESTROY,
};
-struct bpf_ext_analyzer_ops;
+struct bpf_prog_offload_ops;
struct netlink_ext_ack;
struct netdev_bpf {
@@ -826,7 +826,7 @@ struct netdev_bpf {
/* BPF_OFFLOAD_VERIFIER_PREP */
struct {
struct bpf_prog *prog;
- const struct bpf_ext_analyzer_ops *ops; /* callee set */
+ const struct bpf_prog_offload_ops *ops; /* callee set */
} verifier;
/* BPF_OFFLOAD_TRANSLATE, BPF_OFFLOAD_DESTROY */
struct {
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index b88e5ebdc61d..cda2d8350fe1 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -45,7 +45,6 @@ int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
return -ENOMEM;
offload->prog = prog;
- init_waitqueue_head(&offload->verifier_done);
/* Our UNREGISTER notifier will grab bpf_devs_lock, so we are safe
* to assume the netdev doesn't get unregistered as long as we hold
@@ -95,15 +94,28 @@ int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)
if (err)
goto exit_unlock;
- env->dev_ops = data.verifier.ops;
-
+ env->prog->aux->offload->dev_ops = data.verifier.ops;
env->prog->aux->offload->dev_state = true;
- env->prog->aux->offload->verifier_running = true;
exit_unlock:
rtnl_unlock();
return err;
}
+int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
+ int insn_idx, int prev_insn_idx)
+{
+ struct bpf_dev_offload *offload;
+ int ret = -ENODEV;
+
+ down_read(&bpf_devs_lock);
+ offload = env->prog->aux->offload;
+ if (offload->netdev)
+ ret = offload->dev_ops->insn_hook(env, insn_idx, prev_insn_idx);
+ up_read(&bpf_devs_lock);
+
+ return ret;
+}
+
static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
@@ -115,9 +127,6 @@ static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
data.offload.prog = prog;
- if (offload->verifier_running)
- wait_event(offload->verifier_done, !offload->verifier_running);
-
if (offload->dev_state)
WARN_ON(__bpf_offload_ndo(prog, BPF_OFFLOAD_DESTROY, &data));
@@ -130,9 +139,6 @@ void bpf_prog_offload_destroy(struct bpf_prog *prog)
{
struct bpf_dev_offload *offload = prog->aux->offload;
- offload->verifier_running = false;
- wake_up(&offload->verifier_done);
-
rtnl_lock();
down_write(&bpf_devs_lock);
__bpf_prog_offload_destroy(prog);
@@ -144,15 +150,11 @@ void bpf_prog_offload_destroy(struct bpf_prog *prog)
static int bpf_prog_offload_translate(struct bpf_prog *prog)
{
- struct bpf_dev_offload *offload = prog->aux->offload;
struct netdev_bpf data = {};
int ret;
data.offload.prog = prog;
- offload->verifier_running = false;
- wake_up(&offload->verifier_done);
-
rtnl_lock();
ret = __bpf_offload_ndo(prog, BPF_OFFLOAD_TRANSLATE, &data);
rtnl_unlock();
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 48b2901cf483..6b95efad5828 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4341,15 +4341,6 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
return 0;
}
-static int ext_analyzer_insn_hook(struct bpf_verifier_env *env,
- int insn_idx, int prev_insn_idx)
-{
- if (env->dev_ops && env->dev_ops->insn_hook)
- return env->dev_ops->insn_hook(env, insn_idx, prev_insn_idx);
-
- return 0;
-}
-
static int do_check(struct bpf_verifier_env *env)
{
struct bpf_verifier_state *state;
@@ -4431,9 +4422,12 @@ static int do_check(struct bpf_verifier_env *env)
env->allow_ptr_leaks);
}
- err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx);
- if (err)
- return err;
+ if (bpf_prog_is_dev_bound(env->prog->aux)) {
+ err = bpf_prog_offload_verify_insn(env, insn_idx,
+ prev_insn_idx);
+ if (err)
+ return err;
+ }
regs = cur_regs(env);
env->insn_aux_data[insn_idx].seen = true;
@@ -5341,7 +5335,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
env->strict_alignment = true;
- if (env->prog->aux->offload) {
+ if (bpf_prog_is_dev_bound(env->prog->aux)) {
ret = bpf_prog_offload_verifier_prep(env);
if (ret)
goto err_unlock;
--
2.15.1
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