Re: [PATCH v2] x86/sgx: Remove redundant if conditions in sgx_encl_create

[Tianjia Zhang]

On 1/21/21 1:47 AM, Sean Christopherson wrote:
> On Wed, Jan 20, 2021, 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.
> >
> > Reported-by: Jia Zhang <zhang.jia@xxxxxxxxxxxxxxxxx>
> > Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> > Signed-off-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
> > ---
> >   arch/x86/kernel/cpu/sgx/ioctl.c | 9 ++++++---
> >   1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> > index 1c6ecf9fbeff..efad2fb61c76 100644
> > --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> > @@ -66,9 +66,12 @@ 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 (WARN_ONCE(!va_page,
> > +		      "the tail page of the VA page list had free slots\n"))
>
> IMO it's worth trimming down the message to keep this on a single line.  The
> newline isn't necessary, and this code expects a completely empty list, e.g. it
> can be reworded to something like:
>
> 	if (WARN_ONCE(!va_page, "non-empty VA page list before ECREATE"))

Thanks for your suggestion, I have resubmitted a set of patches.

Best regards,
Tianjia