Commit 185da3da authored by Jakob Koschel's avatar Jakob Koschel Committed by Andrii Nakryiko
Browse files

bpf: Replace usage of supported with dedicated list iterator variable 

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use the found variable (existed & supported)
and simply checking if the variable was set, can determine if the
break/goto was hit.

[1] https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/



Signed-off-by: default avatarJakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220331091929.647057-1-jakobkoschel@gmail.com
parent 891663ac

kernel/bpf/bpf_iter.c

+14 −16
Original line number Diff line number Diff line
@@ -330,35 +330,34 @@ static void cache_btf_id(struct bpf_iter_target_info *tinfo, 
bool bpf_iter_prog_supported(struct bpf_prog *prog)

{

	const char *attach_fname = prog->aux->attach_func_name;

	struct bpf_iter_target_info *tinfo = NULL, *iter;

	u32 prog_btf_id = prog->aux->attach_btf_id;

	const char *prefix = BPF_ITER_FUNC_PREFIX;

	struct bpf_iter_target_info *tinfo;

	int prefix_len = strlen(prefix);

	bool supported = false;



	if (strncmp(attach_fname, prefix, prefix_len))

		return false;



	mutex_lock(&targets_mutex);

	list_for_each_entry(tinfo, &targets, list) {

		if (tinfo->btf_id && tinfo->btf_id == prog_btf_id) {

			supported = true;

	list_for_each_entry(iter, &targets, list) {

		if (iter->btf_id && iter->btf_id == prog_btf_id) {

			tinfo = iter;

			break;

		}

		if (!strcmp(attach_fname + prefix_len, tinfo->reg_info->target)) {

			cache_btf_id(tinfo, prog);

			supported = true;

		if (!strcmp(attach_fname + prefix_len, iter->reg_info->target)) {

			cache_btf_id(iter, prog);

			tinfo = iter;

			break;

		}

	}

	mutex_unlock(&targets_mutex);



	if (supported) {

	if (tinfo) {

		prog->aux->ctx_arg_info_size = tinfo->reg_info->ctx_arg_info_size;

		prog->aux->ctx_arg_info = tinfo->reg_info->ctx_arg_info;

	}



	return supported;

	return tinfo != NULL;

}



const struct bpf_func_proto *
@@ -499,12 +498,11 @@ bool bpf_link_is_iter(struct bpf_link *link) 
int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr,

			 struct bpf_prog *prog)

{

	struct bpf_iter_target_info *tinfo = NULL, *iter;

	struct bpf_link_primer link_primer;

	struct bpf_iter_target_info *tinfo;

	union bpf_iter_link_info linfo;

	struct bpf_iter_link *link;

	u32 prog_btf_id, linfo_len;

	bool existed = false;

	bpfptr_t ulinfo;

	int err;
@@ -530,14 +528,14 @@ int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, 


	prog_btf_id = prog->aux->attach_btf_id;

	mutex_lock(&targets_mutex);

	list_for_each_entry(tinfo, &targets, list) {

		if (tinfo->btf_id == prog_btf_id) {

			existed = true;

	list_for_each_entry(iter, &targets, list) {

		if (iter->btf_id == prog_btf_id) {

			tinfo = iter;

			break;

		}

	}

	mutex_unlock(&targets_mutex);

	if (!existed)

	if (!tinfo)

		return -ENOENT;



	link = kzalloc(sizeof(*link), GFP_USER | __GFP_NOWARN);