bpf: Refactor bpf_iter_reg to have separate seq_info member

There is no functionality change for this patch.
Struct bpf_iter_reg is used to register a bpf_iter target,
which includes information for both prog_load, link_create
and seq_file creation.

This patch puts fields related seq_file creation into
a different structure. This will be useful for map
elements iterator where one iterator covers different
map types and different map types may have different
seq_ops, init/fini private_data function and
private_data size.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723184109.590030-1-yhs@fb.com

4 files changed, 30 insertions, 14 deletions

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index dd612b80b9fe..5b2387d6aa1f 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -218,8 +218,8 @@ static int iter_release(struct inode *inode, struct file *file)
 	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
 				 target_private);
 
-	if (iter_priv->tinfo->reg_info->fini_seq_private)
-		iter_priv->tinfo->reg_info->fini_seq_private(seq->private);
+	if (iter_priv->tinfo->reg_info->seq_info->fini_seq_private)
+		iter_priv->tinfo->reg_info->seq_info->fini_seq_private(seq->private);
 
 	bpf_prog_put(iter_priv->prog);
 	seq->private = iter_priv;
@@ -433,16 +433,16 @@ static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
 
 	tinfo = link->tinfo;
 	total_priv_dsize = offsetof(struct bpf_iter_priv_data, target_private) +
-			   tinfo->reg_info->seq_priv_size;
-	priv_data = __seq_open_private(file, tinfo->reg_info->seq_ops,
+			   tinfo->reg_info->seq_info->seq_priv_size;
+	priv_data = __seq_open_private(file, tinfo->reg_info->seq_info->seq_ops,
 				       total_priv_dsize);
 	if (!priv_data) {
 		err = -ENOMEM;
 		goto release_prog;
 	}
 
-	if (tinfo->reg_info->init_seq_private) {
-		err = tinfo->reg_info->init_seq_private(priv_data->target_private);
+	if (tinfo->reg_info->seq_info->init_seq_private) {
+		err = tinfo->reg_info->seq_info->init_seq_private(priv_data->target_private);
 		if (err)
 			goto release_seq_file;
 	}
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c
index 5926c76d854e..1a69241fb1e2 100644
--- a/kernel/bpf/map_iter.c
+++ b/kernel/bpf/map_iter.c
@@ -81,17 +81,21 @@ static const struct seq_operations bpf_map_seq_ops = {
 BTF_ID_LIST(btf_bpf_map_id)
 BTF_ID(struct, bpf_map)
 
-static struct bpf_iter_reg bpf_map_reg_info = {
-	.target			= "bpf_map",
+static const struct bpf_iter_seq_info bpf_map_seq_info = {
 	.seq_ops		= &bpf_map_seq_ops,
 	.init_seq_private	= NULL,
 	.fini_seq_private	= NULL,
 	.seq_priv_size		= sizeof(struct bpf_iter_seq_map_info),
+};
+
+static struct bpf_iter_reg bpf_map_reg_info = {
+	.target			= "bpf_map",
 	.ctx_arg_info_size	= 1,
 	.ctx_arg_info		= {
 		{ offsetof(struct bpf_iter__bpf_map, map),
 		  PTR_TO_BTF_ID_OR_NULL },
 	},
+	.seq_info		= &bpf_map_seq_info,
 };
 
 static int __init bpf_map_iter_init(void)
diff --git a/kernel/bpf/prog_iter.c b/kernel/bpf/prog_iter.c
index 6541b577d69f..53a73c841c13 100644
--- a/kernel/bpf/prog_iter.c
+++ b/kernel/bpf/prog_iter.c
@@ -81,17 +81,21 @@ static const struct seq_operations bpf_prog_seq_ops = {
 BTF_ID_LIST(btf_bpf_prog_id)
 BTF_ID(struct, bpf_prog)
 
-static struct bpf_iter_reg bpf_prog_reg_info = {
-	.target			= "bpf_prog",
+static const struct bpf_iter_seq_info bpf_prog_seq_info = {
 	.seq_ops		= &bpf_prog_seq_ops,
 	.init_seq_private	= NULL,
 	.fini_seq_private	= NULL,
 	.seq_priv_size		= sizeof(struct bpf_iter_seq_prog_info),
+};
+
+static struct bpf_iter_reg bpf_prog_reg_info = {
+	.target			= "bpf_prog",
 	.ctx_arg_info_size	= 1,
 	.ctx_arg_info		= {
 		{ offsetof(struct bpf_iter__bpf_prog, prog),
 		  PTR_TO_BTF_ID_OR_NULL },
 	},
+	.seq_info		= &bpf_prog_seq_info,
 };
 
 static int __init bpf_prog_iter_init(void)
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 1039e52ebd8b..6d9cd23869bf 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -319,25 +319,32 @@ BTF_ID_LIST(btf_task_file_ids)
 BTF_ID(struct, task_struct)
 BTF_ID(struct, file)
 
-static struct bpf_iter_reg task_reg_info = {
-	.target			= "task",
+static const struct bpf_iter_seq_info task_seq_info = {
 	.seq_ops		= &task_seq_ops,
 	.init_seq_private	= init_seq_pidns,
 	.fini_seq_private	= fini_seq_pidns,
 	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_info),
+};
+
+static struct bpf_iter_reg task_reg_info = {
+	.target			= "task",
 	.ctx_arg_info_size	= 1,
 	.ctx_arg_info		= {
 		{ offsetof(struct bpf_iter__task, task),
 		  PTR_TO_BTF_ID_OR_NULL },
 	},
+	.seq_info		= &task_seq_info,
 };
 
-static struct bpf_iter_reg task_file_reg_info = {
-	.target			= "task_file",
+static const struct bpf_iter_seq_info task_file_seq_info = {
 	.seq_ops		= &task_file_seq_ops,
 	.init_seq_private	= init_seq_pidns,
 	.fini_seq_private	= fini_seq_pidns,
 	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_file_info),
+};
+
+static struct bpf_iter_reg task_file_reg_info = {
+	.target			= "task_file",
 	.ctx_arg_info_size	= 2,
 	.ctx_arg_info		= {
 		{ offsetof(struct bpf_iter__task_file, task),
@@ -345,6 +352,7 @@ static struct bpf_iter_reg task_file_reg_info = {
 		{ offsetof(struct bpf_iter__task_file, file),
 		  PTR_TO_BTF_ID_OR_NULL },
 	},
+	.seq_info		= &task_file_seq_info,
 };
 
 static int __init task_iter_init(void)