Re: [PATCH v5 3/3] x86/sgx: Remove redundant if conditions in sgx_encl_create

[Tianjia Zhang]

On 2/16/21 4:29 PM, Jarkko Sakkinen wrote:
> On Tue, Feb 16, 2021 at 11:31:33AM +0800, Tianjia Zhang wrote:
> > In this scenario, there is no case where va_page is NULL, and
> > the error has been checked. The if-condition statement here is
> > redundant, so remove the condition detection.
> >
> > Signed-off-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
> > Acked-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > ---
> >   arch/x86/kernel/cpu/sgx/ioctl.c | 7 ++++---
> >   1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> > index 1c6ecf9fbeff..719c21cca569 100644
> > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > @@ -66,9 +66,10 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
> >   	va_page = sgx_encl_grow(encl);
> >   	if (IS_ERR(va_page))
> >   		return PTR_ERR(va_page);
> > -	else if (va_page)
> > -		list_add(&va_page->list, &encl->va_pages);
> > -	/* else the tail page of the VA page list had free slots. */
> > +	if (!va_page)
> > +		return -EIO;
>
> Why this check?

The value of va_page may be a negative error value, it may be NULL, or 
it may be a valid pointer, so check this return value.

Tianjia

> > +
> > +	list_add(&va_page->list, &encl->va_pages);
> >   
> >   	/* The extra page goes to SECS. */
> >   	encl_size = secs->size + PAGE_SIZE;
> > --
> > 2.19.1.3.ge56e4f7
>
> /Jarkko