diff mbox series

[bpf-next] bpf: Fix a typo in comment for DFS algorithm

Message ID 20221026025941.2621795-1-xukuohai@huaweicloud.com
State New
Headers
Series [bpf-next] bpf: Fix a typo in comment for DFS algorithm |

Commit Message

Xu Kuohai Oct. 26, 2022, 2:59 a.m. UTC 
  From: Xu Kuohai <xukuohai@huawei.com>

There is a typo in comment for DFS algorithm in bpf/verifier.c. The top
element should not be popped until all its neighbors have been checked.
Fix it.

Fixes: 475fb78fbf48 ("bpf: verifier (add branch/goto checks)")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 kernel/bpf/verifier.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Alexei Starovoitov Oct. 26, 2022, 6:32 a.m. UTC | #1 
On Tue, Oct 25, 2022 at 7:42 PM Xu Kuohai <xukuohai@huaweicloud.com> wrote:
>
> From: Xu Kuohai <xukuohai@huawei.com>
>
> There is a typo in comment for DFS algorithm in bpf/verifier.c. The top
> element should not be popped until all its neighbors have been checked.
> Fix it.
>
> Fixes: 475fb78fbf48 ("bpf: verifier (add branch/goto checks)")
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>  kernel/bpf/verifier.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index b83a8d420520..96ba5ea6d1a6 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -10662,7 +10662,7 @@ static int check_return_code(struct bpf_verifier_env *env)
>   * 3      let S be a stack
>   * 4      S.push(v)
>   * 5      while S is not empty
> - * 6            t <- S.pop()
> + * 6            t <- S.top()

Even with this fix the comment is not quite accurate.
I wonder whether we should keep it or delete it completely.
At least please use 'peek' instead of 'top'.
Bagas Sanjaya Oct. 26, 2022, 7:52 a.m. UTC | #2 
On Tue, Oct 25, 2022 at 11:32:55PM -0700, Alexei Starovoitov wrote:
> On Tue, Oct 25, 2022 at 7:42 PM Xu Kuohai <xukuohai@huaweicloud.com> wrote:
> >
> > From: Xu Kuohai <xukuohai@huawei.com>
> >
> > There is a typo in comment for DFS algorithm in bpf/verifier.c. The top
> > element should not be popped until all its neighbors have been checked.
> > Fix it.
> >
> > Fixes: 475fb78fbf48 ("bpf: verifier (add branch/goto checks)")
> > Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> > ---
> >  kernel/bpf/verifier.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index b83a8d420520..96ba5ea6d1a6 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -10662,7 +10662,7 @@ static int check_return_code(struct bpf_verifier_env *env)
> >   * 3      let S be a stack
> >   * 4      S.push(v)
> >   * 5      while S is not empty
> > - * 6            t <- S.pop()
> > + * 6            t <- S.top()
> 
> Even with this fix the comment is not quite accurate.
> I wonder whether we should keep it or delete it completely.
> At least please use 'peek' instead of 'top'.

I think the comment should be in words (like other code comments in the
kernel) instead.
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index b83a8d420520..96ba5ea6d1a6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -10662,7 +10662,7 @@  static int check_return_code(struct bpf_verifier_env *env)
  * 3      let S be a stack
  * 4      S.push(v)
  * 5      while S is not empty
- * 6            t <- S.pop()
+ * 6            t <- S.top()
  * 7            if t is what we're looking for:
  * 8                return t
  * 9            for all edges e in G.adjacentEdges(t) do