Re: [PATCH -next] binder: simplify the return expression of binder_mmap

Liu Shixin
2020-09-21T10:42:48Z

On 2020/9/21 16:08, Christian Brauner wrote:

> On Mon, Sep 21, 2020 at 04:24:23PM +0800, Liu Shixin wrote:
>> Simplify the return expression.
>>
>> Signed-off-by: Liu Shixin <liushixin2@huawei.com>
>> ---
> Why not is all I can really say. :) But if this is about simplifying you
> could get rid of the "ret" and "failure string" variables, and the goto
> in that function completely by doing sm like this (__completely
> untested__):

Thanks for your advice. I will modify and test it.

Regards,
Liu Shixin

>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index f936530a19b0..26f4dc81b008 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -5182,9 +5182,7 @@ 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;
> @@ -5196,9 +5194,9 @@ 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;
> @@ -5206,15 +5204,7 @@ 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);
> }
>
> Christian
> .
>