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authorJakob Koschel <jakobkoschel@gmail.com>2022-03-31 11:19:29 +0200
committerAndrii Nakryiko <andrii@kernel.org>2022-04-03 16:33:36 -0700
commit185da3da9379948ffbe45051b16d526c428fb06e (patch)
treee46c77b38a802b125e37a302a372945c78ba980f /kernel/bpf/bpf_iter.c
parent891663ace74c23321a40f4bae13e45a1803d5e20 (diff)
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: Jakob Koschel <jakobkoschel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220331091929.647057-1-jakobkoschel@gmail.com
Diffstat (limited to 'kernel/bpf/bpf_iter.c')
-rw-r--r--kernel/bpf/bpf_iter.c30
1 files changed, 14 insertions, 16 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 110029ede71e..dea920b3b840 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -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);