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Message-Id: <20200828193603.335512-3-sdf@google.com>
Date: Fri, 28 Aug 2020 12:35:57 -0700
From: Stanislav Fomichev <sdf@...gle.com>
To: netdev@...r.kernel.org, bpf@...r.kernel.org
Cc: davem@...emloft.net, ast@...nel.org, daniel@...earbox.net,
YiFei Zhu <zhuyifei@...gle.com>,
YiFei Zhu <zhuyifei1999@...il.com>,
Stanislav Fomichev <sdf@...gle.com>
Subject: [PATCH bpf-next v3 2/8] bpf: Add BPF_PROG_BIND_MAP syscall
From: YiFei Zhu <zhuyifei@...gle.com>
This syscall binds a map to a program. -EEXIST if the map is
already bound to the program.
Cc: YiFei Zhu <zhuyifei1999@...il.com>
Signed-off-by: YiFei Zhu <zhuyifei@...gle.com>
Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
---
include/uapi/linux/bpf.h | 7 ++++
kernel/bpf/syscall.c | 65 ++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 7 ++++
3 files changed, 79 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ef7af384f5ee..d232c71c4560 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -124,6 +124,7 @@ enum bpf_cmd {
BPF_ENABLE_STATS,
BPF_ITER_CREATE,
BPF_LINK_DETACH,
+ BPF_PROG_BIND_MAP,
};
enum bpf_map_type {
@@ -650,6 +651,12 @@ union bpf_attr {
__u32 flags;
} iter_create;
+ struct { /* struct used by BPF_PROG_BIND_MAP command */
+ __u32 prog_fd;
+ __u32 map_fd;
+ __u32 flags; /* extra flags */
+ } prog_bind_map;
+
} __attribute__((aligned(8)));
/* The description below is an attempt at providing documentation to eBPF
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c9b8a97fbbdf..8c1fad2826d1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4154,6 +4154,68 @@ static int bpf_iter_create(union bpf_attr *attr)
return err;
}
+#define BPF_PROG_BIND_MAP_LAST_FIELD prog_bind_map.flags
+
+static int bpf_prog_bind_map(union bpf_attr *attr)
+{
+ struct bpf_prog *prog;
+ struct bpf_map *map;
+ struct bpf_map **used_maps_old, **used_maps_new;
+ int i, ret = 0;
+
+ if (CHECK_ATTR(BPF_PROG_BIND_MAP))
+ return -EINVAL;
+
+ if (attr->prog_bind_map.flags)
+ return -EINVAL;
+
+ prog = bpf_prog_get(attr->prog_bind_map.prog_fd);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+
+ map = bpf_map_get(attr->prog_bind_map.map_fd);
+ if (IS_ERR(map)) {
+ ret = PTR_ERR(map);
+ goto out_prog_put;
+ }
+
+ mutex_lock(&prog->aux->used_maps_mutex);
+
+ used_maps_old = prog->aux->used_maps;
+
+ for (i = 0; i < prog->aux->used_map_cnt; i++)
+ if (used_maps_old[i] == map) {
+ ret = -EEXIST;
+ goto out_unlock;
+ }
+
+ used_maps_new = kmalloc_array(prog->aux->used_map_cnt + 1,
+ sizeof(used_maps_new[0]),
+ GFP_KERNEL);
+ if (!used_maps_new) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ memcpy(used_maps_new, used_maps_old,
+ sizeof(used_maps_old[0]) * prog->aux->used_map_cnt);
+ used_maps_new[prog->aux->used_map_cnt] = map;
+
+ prog->aux->used_map_cnt++;
+ prog->aux->used_maps = used_maps_new;
+
+ kfree(used_maps_old);
+
+out_unlock:
+ mutex_unlock(&prog->aux->used_maps_mutex);
+
+ if (ret)
+ bpf_map_put(map);
+out_prog_put:
+ bpf_prog_put(prog);
+ return ret;
+}
+
SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
{
union bpf_attr attr;
@@ -4287,6 +4349,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
case BPF_LINK_DETACH:
err = link_detach(&attr);
break;
+ case BPF_PROG_BIND_MAP:
+ err = bpf_prog_bind_map(&attr);
+ break;
default:
err = -EINVAL;
break;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index ef7af384f5ee..d232c71c4560 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -124,6 +124,7 @@ enum bpf_cmd {
BPF_ENABLE_STATS,
BPF_ITER_CREATE,
BPF_LINK_DETACH,
+ BPF_PROG_BIND_MAP,
};
enum bpf_map_type {
@@ -650,6 +651,12 @@ union bpf_attr {
__u32 flags;
} iter_create;
+ struct { /* struct used by BPF_PROG_BIND_MAP command */
+ __u32 prog_fd;
+ __u32 map_fd;
+ __u32 flags; /* extra flags */
+ } prog_bind_map;
+
} __attribute__((aligned(8)));
/* The description below is an attempt at providing documentation to eBPF
--
2.28.0.402.g5ffc5be6b7-goog
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