linux-kernel - Re: [PATCH v3 -next] binder: simplify the return expression of binder

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Date:   Fri, 2 Oct 2020 16:18:13 +0200
From:   Martijn Coenen <maco@...roid.com>
To:     Liu Shixin <liushixin2@...wei.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christian Brauner <christian@...uner.io>,
        Arve Hjønnevåg <arve@...roid.com>,
        Todd Kjos <tkjos@...roid.com>,
        Joel Fernandes <joel@...lfernandes.org>,
        Hridya Valsaraju <hridya@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        "open list:ANDROID DRIVERS" <devel@...verdev.osuosl.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 -next] binder: simplify the return expression of binder_mmap

Thanks!

On Tue, Sep 29, 2020 at 3:30 AM Liu Shixin <liushixin2@...wei.com> wrote:
>
> Simplify the return expression.
>
> Signed-off-by: Liu Shixin <liushixin2@...wei.com>

Acked-by: Martijn Coenen <maco@...roid.com>

> ---
> v3: Add the change description.
> v2: Get rid of the "ret" and "failure string" variables.
> v1: Simplify the return expression.
> ---
>  drivers/android/binder.c | 18 ++++--------------
>  1 file changed, 4 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 37a505c41dec..49c0700816a5 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -5180,9 +5180,7 @@ static const struct vm_operations_struct binder_vm_ops = {
>
>  static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
>  {
> -       int ret;
>         struct binder_proc *proc = filp->private_data;
> -       const char *failure_string;
>
>         if (proc->tsk != current->group_leader)
>                 return -EINVAL;
> @@ -5194,9 +5192,9 @@ static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
>                      (unsigned long)pgprot_val(vma->vm_page_prot));
>
>         if (vma->vm_flags & FORBIDDEN_MMAP_FLAGS) {
> -               ret = -EPERM;
> -               failure_string = "bad vm_flags";
> -               goto err_bad_arg;
> +               pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
> +                      proc->pid, vma->vm_start, vma->vm_end, "bad vm_flags", -EPERM);
> +               return -EPERM;
>         }
>         vma->vm_flags |= VM_DONTCOPY | VM_MIXEDMAP;
>         vma->vm_flags &= ~VM_MAYWRITE;
> @@ -5204,15 +5202,7 @@ static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
>         vma->vm_ops = &binder_vm_ops;
>         vma->vm_private_data = proc;
>
> -       ret = binder_alloc_mmap_handler(&proc->alloc, vma);
> -       if (ret)
> -               return ret;
> -       return 0;
> -
> -err_bad_arg:
> -       pr_err("%s: %d %lx-%lx %s failed %d\n", __func__,
> -              proc->pid, vma->vm_start, vma->vm_end, failure_string, ret);
> -       return ret;
> +       return binder_alloc_mmap_handler(&proc->alloc, vma);
>  }
>
>  static int binder_open(struct inode *nodp, struct file *filp)
> --
> 2.25.1
>