Re: [bp:tip-x86-sgx 11/25] arch/x86/kernel/cpu/sgx/encl.h:45:19: warning: variable 'encl' set but not used

[Jarkko Sakkinen <jarkko@kernel.org>]

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On Wed, Nov 18, 2020 at 11:42:54AM +0100, Borislav Petkov wrote:
> On Wed, Nov 18, 2020 at 11:23:55AM +0800, kernel test robot wrote:
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git tip-x86-sgx
> > head:   56e2d0eff4f8db87cf77d9c8481041878177c680
> > commit: 4b634f57cac2e1d28cfa0ca961e561362fc3f957 [11/25] x86/sgx: Add an SGX misc driver interface
> > config: x86_64-allyesconfig (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> > reproduce (this is a W=1 build):
> >         # https://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git/commit/?id=4b634f57cac2e1d28cfa0ca961e561362fc3f957
> >         git remote add bp https://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git
> >         git fetch --no-tags bp tip-x86-sgx
> >         git checkout 4b634f57cac2e1d28cfa0ca961e561362fc3f957
> >         # save the attached .config to linux build tree
> >         make W=1 ARCH=x86_64 
> > 
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@intel.com>
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >    In file included from arch/x86/kernel/cpu/sgx/driver.c:11:
> >    arch/x86/kernel/cpu/sgx/encl.h: In function 'sgx_encl_find':
> > >> arch/x86/kernel/cpu/sgx/encl.h:45:19: warning: variable 'encl' set but not used [-Wunused-but-set-variable]
> >       45 |  struct sgx_encl *encl;
> >          |                   ^~~~
> > 
> > vim +/encl +45 arch/x86/kernel/cpu/sgx/encl.h
> > 
> >     40	
> >     41	static inline int sgx_encl_find(struct mm_struct *mm, unsigned long addr,
> >     42					struct vm_area_struct **vma)
> >     43	{
> >     44		struct vm_area_struct *result;
> >   > 45		struct sgx_encl *encl;
> >     46	
> >     47		result = find_vma(mm, addr);
> >     48		if (!result || result->vm_ops != &sgx_vm_ops || addr < result->vm_start)
> >     49			return -EINVAL;
> >     50	
> >     51		encl = result->vm_private_data;
> 
> Looks like that encl needs to go, judging by:
> 
> * Do not check !vm_private_data in sgx_encl_find(), as the enclave is
>   created at VFS open.
> 
> in patch 11.
> 
> Jarkko?

Yes, it is useless.

> -- 
> Regards/Gruss,
>     Boris.
> 
> SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 36809, AG Nürnberg
 

 /Jarkko