[PATCH] drm/i915: Check input parameter for NULL

[kernel test robot]

Hi Yongzhi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on drm-intel/for-linux-next]
[also build test ERROR on v5.17-rc5 next-20220217]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Yongzhi-Liu/drm-i915-Check-input-parameter-for-NULL/20220221-225508
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: i386-randconfig-a004-20220221 (https://download.01.org/0day-ci/archive/20220222/202202220935.3r4emO4y-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/c54be425a38b3f4cb82c5badecf6b343f9e24a90
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Yongzhi-Liu/drm-i915-Check-input-parameter-for-NULL/20220221-225508
        git checkout c54be425a38b3f4cb82c5badecf6b343f9e24a90
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>

All errors (new ones prefixed by >>):

   drivers/gpu/drm/i915/gem/i915_gem_phys.c: In function 'i915_gem_object_put_pages_phys':
>> drivers/gpu/drm/i915/gem/i915_gem_phys.c:100:2: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
     100 |  dma_addr_t dma = sg_dma_address(pages->sgl);
         |  ^~~~~~~~~~
   cc1: all warnings being treated as errors


vim +100 drivers/gpu/drm/i915/gem/i915_gem_phys.c

f033428db28bdf Chris Wilson      2019-05-28   93  
a61170975718d5 Maarten Lankhorst 2021-03-23   94  void
f033428db28bdf Chris Wilson      2019-05-28   95  i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
f033428db28bdf Chris Wilson      2019-05-28   96  			       struct sg_table *pages)
f033428db28bdf Chris Wilson      2019-05-28   97  {
c54be425a38b3f Yongzhi Liu       2022-02-21   98  	if (!pages)
c54be425a38b3f Yongzhi Liu       2022-02-21   99  		return;
c6790dc22312f5 Chris Wilson      2020-02-02 @100  	dma_addr_t dma = sg_dma_address(pages->sgl);
c6790dc22312f5 Chris Wilson      2020-02-02  101  	void *vaddr = sg_page(pages->sgl);
c6790dc22312f5 Chris Wilson      2020-02-02  102  
f033428db28bdf Chris Wilson      2019-05-28  103  	__i915_gem_object_release_shmem(obj, pages, false);
f033428db28bdf Chris Wilson      2019-05-28  104  
f033428db28bdf Chris Wilson      2019-05-28  105  	if (obj->mm.dirty) {
f033428db28bdf Chris Wilson      2019-05-28  106  		struct address_space *mapping = obj->base.filp->f_mapping;
c6790dc22312f5 Chris Wilson      2020-02-02  107  		void *src = vaddr;
f033428db28bdf Chris Wilson      2019-05-28  108  		int i;
f033428db28bdf Chris Wilson      2019-05-28  109  
f033428db28bdf Chris Wilson      2019-05-28  110  		for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
f033428db28bdf Chris Wilson      2019-05-28  111  			struct page *page;
f033428db28bdf Chris Wilson      2019-05-28  112  			char *dst;
f033428db28bdf Chris Wilson      2019-05-28  113  
f033428db28bdf Chris Wilson      2019-05-28  114  			page = shmem_read_mapping_page(mapping, i);
f033428db28bdf Chris Wilson      2019-05-28  115  			if (IS_ERR(page))
f033428db28bdf Chris Wilson      2019-05-28  116  				continue;
f033428db28bdf Chris Wilson      2019-05-28  117  
f033428db28bdf Chris Wilson      2019-05-28  118  			dst = kmap_atomic(page);
c6790dc22312f5 Chris Wilson      2020-02-02  119  			drm_clflush_virt_range(src, PAGE_SIZE);
c6790dc22312f5 Chris Wilson      2020-02-02  120  			memcpy(dst, src, PAGE_SIZE);
f033428db28bdf Chris Wilson      2019-05-28  121  			kunmap_atomic(dst);
f033428db28bdf Chris Wilson      2019-05-28  122  
f033428db28bdf Chris Wilson      2019-05-28  123  			set_page_dirty(page);
f033428db28bdf Chris Wilson      2019-05-28  124  			if (obj->mm.madv == I915_MADV_WILLNEED)
f033428db28bdf Chris Wilson      2019-05-28  125  				mark_page_accessed(page);
f033428db28bdf Chris Wilson      2019-05-28  126  			put_page(page);
c6790dc22312f5 Chris Wilson      2020-02-02  127  
c6790dc22312f5 Chris Wilson      2020-02-02  128  			src += PAGE_SIZE;
f033428db28bdf Chris Wilson      2019-05-28  129  		}
f033428db28bdf Chris Wilson      2019-05-28  130  		obj->mm.dirty = false;
f033428db28bdf Chris Wilson      2019-05-28  131  	}
f033428db28bdf Chris Wilson      2019-05-28  132  
f033428db28bdf Chris Wilson      2019-05-28  133  	sg_free_table(pages);
f033428db28bdf Chris Wilson      2019-05-28  134  	kfree(pages);
f033428db28bdf Chris Wilson      2019-05-28  135  
8ff5446a7ca47c Thomas Zimmermann 2021-01-28  136  	dma_free_coherent(obj->base.dev->dev,
c6790dc22312f5 Chris Wilson      2020-02-02  137  			  roundup_pow_of_two(obj->base.size),
c6790dc22312f5 Chris Wilson      2020-02-02  138  			  vaddr, dma);
f033428db28bdf Chris Wilson      2019-05-28  139  }
f033428db28bdf Chris Wilson      2019-05-28  140  

---
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