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Date:   Tue, 19 Nov 2019 11:30:30 -0800
In-Reply-To: <20191119193036.92831-1-brianvv@google.com>
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References: <20191119193036.92831-1-brianvv@google.com>
Subject: [PATCH v2 bpf-next 3/9] bpf: add generic support for update and
 delete batch ops
From:   Brian Vazquez <brianvv@google.com>
To:     Brian Vazquez <brianvv.kernel@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        "David S . Miller" <davem@davemloft.net>
Cc:     Yonghong Song <yhs@fb.com>, Stanislav Fomichev <sdf@google.com>,
        Petar Penkov <ppenkov@google.com>,
        Willem de Bruijn <willemb@google.com>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, Brian Vazquez <brianvv@google.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

This commit adds generic support for update and delete batch ops that
can be used for almost all the bpf maps. These commands share the same
UAPI attr that lookup and lookup_and_delete batch ops use and the
syscall commands are:

  BPF_MAP_UPDATE_BATCH
  BPF_MAP_DELETE_BATCH

The main difference between update/delete and lookup/lookup_and_delete
batch ops is that for update/delete keys/values must be specified for
userspace and because of that, neither in_batch nor out_batch are used.

Suggested-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h      |  10 ++++
 include/uapi/linux/bpf.h |   2 +
 kernel/bpf/syscall.c     | 126 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 767a823dbac74..96a19e1fd2b5b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -46,6 +46,10 @@ struct bpf_map_ops {
 	int (*map_lookup_and_delete_batch)(struct bpf_map *map,
 					   const union bpf_attr *attr,
 					   union bpf_attr __user *uattr);
+	int (*map_update_batch)(struct bpf_map *map, const union bpf_attr *attr,
+				union bpf_attr __user *uattr);
+	int (*map_delete_batch)(struct bpf_map *map, const union bpf_attr *attr,
+				union bpf_attr __user *uattr);
 
 	/* funcs callable from userspace and from eBPF programs */
 	void *(*map_lookup_elem)(struct bpf_map *map, void *key);
@@ -808,6 +812,12 @@ int  generic_map_lookup_batch(struct bpf_map *map,
 int  generic_map_lookup_and_delete_batch(struct bpf_map *map,
 					 const union bpf_attr *attr,
 					 union bpf_attr __user *uattr);
+int  generic_map_update_batch(struct bpf_map *map,
+			      const union bpf_attr *attr,
+			      union bpf_attr __user *uattr);
+int  generic_map_delete_batch(struct bpf_map *map,
+			      const union bpf_attr *attr,
+			      union bpf_attr __user *uattr);
 
 extern int sysctl_unprivileged_bpf_disabled;
 
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e60b7b7cda61a..0f6ff0c4d79dd 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -109,6 +109,8 @@ enum bpf_cmd {
 	BPF_BTF_GET_NEXT_ID,
 	BPF_MAP_LOOKUP_BATCH,
 	BPF_MAP_LOOKUP_AND_DELETE_BATCH,
+	BPF_MAP_UPDATE_BATCH,
+	BPF_MAP_DELETE_BATCH,
 };
 
 enum bpf_map_type {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d0d3d0e0eaca4..06e1bcf40fb8d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1127,6 +1127,120 @@ static int map_get_next_key(union bpf_attr *attr)
 	return err;
 }
 
+int generic_map_delete_batch(struct bpf_map *map,
+			     const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	void __user *keys = u64_to_user_ptr(attr->batch.keys);
+	int ufd = attr->map_fd;
+	u32 cp, max_count;
+	struct fd f;
+	void *key;
+	int err;
+
+	f = fdget(ufd);
+	if (attr->batch.elem_flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	if ((attr->batch.elem_flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	err = -ENOMEM;
+	for (cp = 0; cp < max_count; cp++) {
+		key = __bpf_copy_key(keys + cp * map->key_size, map->key_size);
+		if (IS_ERR(key)) {
+			err = PTR_ERR(key);
+			break;
+		}
+
+		if (err)
+			break;
+		if (bpf_map_is_dev_bound(map)) {
+			err = bpf_map_offload_delete_elem(map, key);
+			break;
+		}
+
+		preempt_disable();
+		__this_cpu_inc(bpf_prog_active);
+		rcu_read_lock();
+		err = map->ops->map_delete_elem(map, key);
+		rcu_read_unlock();
+		__this_cpu_dec(bpf_prog_active);
+		preempt_enable();
+		maybe_wait_bpf_programs(map);
+		if (err)
+			break;
+	}
+	if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
+		err = -EFAULT;
+err_put:
+	return err;
+}
+int generic_map_update_batch(struct bpf_map *map,
+			     const union bpf_attr *attr,
+			     union bpf_attr __user *uattr)
+{
+	void __user *values = u64_to_user_ptr(attr->batch.values);
+	void __user *keys = u64_to_user_ptr(attr->batch.keys);
+	u32 value_size, cp, max_count;
+	int ufd = attr->map_fd;
+	void *key, *value;
+	struct fd f;
+	int err;
+
+	f = fdget(ufd);
+	if (attr->batch.elem_flags & ~BPF_F_LOCK)
+		return -EINVAL;
+
+	if ((attr->batch.elem_flags & BPF_F_LOCK) &&
+	    !map_value_has_spin_lock(map)) {
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	value_size = bpf_map_value_size(map);
+
+	max_count = attr->batch.count;
+	if (!max_count)
+		return 0;
+
+	err = -ENOMEM;
+	value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
+	if (!value)
+		goto err_put;
+
+	for (cp = 0; cp < max_count; cp++) {
+		key = __bpf_copy_key(keys + cp * map->key_size, map->key_size);
+		if (IS_ERR(key)) {
+			err = PTR_ERR(key);
+			break;
+		}
+		err = -EFAULT;
+		if (copy_from_user(value, values + cp * value_size, value_size))
+			break;
+
+		err = bpf_map_update_value(map, f, key, value,
+					   attr->batch.elem_flags);
+
+		if (err)
+			break;
+	}
+
+	if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp)))
+		err = -EFAULT;
+
+	kfree(value);
+err_put:
+	return err;
+}
+
 static int __generic_map_lookup_batch(struct bpf_map *map,
 				      const union bpf_attr *attr,
 				      union bpf_attr __user *uattr,
@@ -3117,8 +3231,12 @@ static int bpf_map_do_batch(const union bpf_attr *attr,
 
 	if (cmd == BPF_MAP_LOOKUP_BATCH)
 		BPF_DO_BATCH(map->ops->map_lookup_batch);
-	else
+	else if (cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH)
 		BPF_DO_BATCH(map->ops->map_lookup_and_delete_batch);
+	else if (cmd == BPF_MAP_UPDATE_BATCH)
+		BPF_DO_BATCH(map->ops->map_update_batch);
+	else
+		BPF_DO_BATCH(map->ops->map_delete_batch);
 
 err_put:
 	fdput(f);
@@ -3229,6 +3347,12 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
 		err = bpf_map_do_batch(&attr, uattr,
 				       BPF_MAP_LOOKUP_AND_DELETE_BATCH);
 		break;
+	case BPF_MAP_UPDATE_BATCH:
+		err = bpf_map_do_batch(&attr, uattr, BPF_MAP_UPDATE_BATCH);
+		break;
+	case BPF_MAP_DELETE_BATCH:
+		err = bpf_map_do_batch(&attr, uattr, BPF_MAP_DELETE_BATCH);
+		break;
 	default:
 		err = -EINVAL;
 		break;
-- 
2.24.0.432.g9d3f5f5b63-goog