[PATCH 2/2] pidns 2/2: rewrite copy_pid_ns()

[PATCH 2/2] pidns 2/2: rewrite copy_pid_ns()

[Alexey Dobriyan]

copy_pid_ns() is a perfect example of a case where unwinding leads to more
code and makes it less clear. Watch the diffstat.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
 kernel/pid_namespace.c |   18 +++---------------
 1 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 495d5de..821722a 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -116,23 +116,11 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
 
 struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
 {
-	struct pid_namespace *new_ns;
-
-	BUG_ON(!old_ns);
-	new_ns = get_pid_ns(old_ns);
 	if (!(flags & CLONE_NEWPID))
-		goto out;
-
-	new_ns = ERR_PTR(-EINVAL);
+		return get_pid_ns(old_ns);
 	if (flags & CLONE_THREAD)
-		goto out_put;
-
-	new_ns = create_pid_namespace(old_ns);
-
-out_put:
-	put_pid_ns(old_ns);
-out:
-	return new_ns;
+		return ERR_PTR(-EINVAL);
+	return create_pid_namespace(old_ns);
 }
 
 void free_pid_ns(struct kref *kref)

Re: [PATCH 2/2] pidns 2/2: rewrite copy_pid_ns()

[Sukadev Bhattiprolu]

Alexey Dobriyan [adobriyan@gmail.com] wrote:
| copy_pid_ns() is a perfect example of a case where unwinding leads to more
| code and makes it less clear. Watch the diffstat.

Yes, its cleaner this way :-)

| 
| Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>

| ---
|  kernel/pid_namespace.c |   18 +++---------------
|  1 files changed, 3 insertions(+), 15 deletions(-)
| 
| diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
| index 495d5de..821722a 100644
| --- a/kernel/pid_namespace.c
| +++ b/kernel/pid_namespace.c
| @@ -116,23 +116,11 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
| 
|  struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
|  {
| -	struct pid_namespace *new_ns;
| -
| -	BUG_ON(!old_ns);
| -	new_ns = get_pid_ns(old_ns);
|  	if (!(flags & CLONE_NEWPID))
| -		goto out;
| -
| -	new_ns = ERR_PTR(-EINVAL);
| +		return get_pid_ns(old_ns);
|  	if (flags & CLONE_THREAD)
| -		goto out_put;
| -
| -	new_ns = create_pid_namespace(old_ns);
| -
| -out_put:
| -	put_pid_ns(old_ns);
| -out:
| -	return new_ns;
| +		return ERR_PTR(-EINVAL);
| +	return create_pid_namespace(old_ns);
|  }
| 
|  void free_pid_ns(struct kref *kref)
| --
| To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
| the body of a message to majordomo@vger.kernel.org
| More majordomo info at  http://vger.kernel.org/majordomo-info.html
| Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 2/2] pidns 2/2: rewrite copy_pid_ns()

[Serge E. Hallyn]

Quoting Alexey Dobriyan (adobriyan@gmail.com):
> copy_pid_ns() is a perfect example of a case where unwinding leads to more
> code and makes it less clear. Watch the diffstat.
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Nice.

Reviewed-by: Serge Hallyn <serue@us.ibm.com>

thanks,
-serge

> ---
>  kernel/pid_namespace.c |   18 +++---------------
>  1 files changed, 3 insertions(+), 15 deletions(-)
> 
> diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
> index 495d5de..821722a 100644
> --- a/kernel/pid_namespace.c
> +++ b/kernel/pid_namespace.c
> @@ -116,23 +116,11 @@ static void destroy_pid_namespace(struct pid_namespace *ns)
> 
>  struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
>  {
> -	struct pid_namespace *new_ns;
> -
> -	BUG_ON(!old_ns);
> -	new_ns = get_pid_ns(old_ns);
>  	if (!(flags & CLONE_NEWPID))
> -		goto out;
> -
> -	new_ns = ERR_PTR(-EINVAL);
> +		return get_pid_ns(old_ns);
>  	if (flags & CLONE_THREAD)
> -		goto out_put;
> -
> -	new_ns = create_pid_namespace(old_ns);
> -
> -out_put:
> -	put_pid_ns(old_ns);
> -out:
> -	return new_ns;
> +		return ERR_PTR(-EINVAL);
> +	return create_pid_namespace(old_ns);
>  }
> 
>  void free_pid_ns(struct kref *kref)
> _______________________________________________
> Containers mailing list
> Containers@lists.linux-foundation.org
> https://lists.linux-foundation.org/mailman/listinfo/containers