Re: [PATCH v2] gpu: drm: gma500: Change return type to vm_fault_t

[kbuild test robot]

Hi Souptick,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm/drm-next]
[also build test WARNING on v4.17-rc6]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:    
https://github.com/0day-ci/linux/commits/Souptick-Joarder/gpu-drm-gma500-Change-return-type-to-vm_fault_t/20180526-084629
base:   git://people.freedesktop.org/~airlied/linux.git drm-next
config: x86_64-randconfig-x013-201820 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/gpu//drm/gma500/framebuffer.c: In function 'psbfb_vm_fault':
>> drivers/gpu//drm/gma500/framebuffer.c:143:9: warning: 'ret' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]
     return ret;
            ^~~

vim +/ret +143 drivers/gpu//drm/gma500/framebuffer.c

   113  
   114  static vm_fault_t psbfb_vm_fault(struct vm_fault *vmf)
   115  {
   116          struct vm_area_struct *vma = vmf->vma;
   117          struct psb_framebuffer *psbfb = vma->vm_private_data;
   118          struct drm_device *dev = psbfb->base.dev;
   119          struct drm_psb_private *dev_priv = dev->dev_private;
   120          int page_num;
   121          int i;
   122          unsigned long address;
   123          vm_fault_t ret;
   124          unsigned long pfn;
   125          unsigned long phys_addr = (unsigned long)dev_priv->stolen_base +
   126                                    psbfb->gtt->offset;
   127  
   128          page_num = vma_pages(vma);
   129          address = vmf->address - (vmf->pgoff << PAGE_SHIFT);
   130  
   131          vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
   132  
   133          for (i = 0; i < page_num; i++) {
   134                  pfn = (phys_addr >> PAGE_SHIFT);
   135  
   136                  ret = vmf_insert_mixed(vma, address,
   137                                  __pfn_to_pfn_t(pfn, PFN_DEV));
   138                  if (unlikely(ret & VM_FAULT_ERROR))
   139                          break;
   140                  address += PAGE_SIZE;
   141                  phys_addr += PAGE_SIZE;
   142          }
 > 143          return ret;
   144  }
   145  

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0-DAY kernel test infrastructure                Open Source Technology Center
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