Hi Kees,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.4-rc1 next-20191002]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Kees-Cook/dma-mapping-Lift-address-space-checks-out-of-debug-code/20191003-060622
config: i386-randconfig-c004-201939 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-13) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/bug.h:83:0,
                    from include/linux/bug.h:5,
                    from include/linux/debug_locks.h:7,
                    from include/linux/lockdep.h:28,
                    from include/linux/spinlock_types.h:18,
                    from include/linux/mutex.h:16,
                    from include/linux/kernfs.h:12,
                    from include/linux/sysfs.h:16,
                    from include/linux/kobject.h:20,
                    from include/linux/of.h:17,
                    from include/linux/irqdomain.h:35,
                    from include/linux/acpi.h:13,
                    from drivers/gpu/drm/i915/i915_drv.c:30:
   include/linux/dma-mapping.h: In function 'dma_map_single_attrs':
>> include/linux/dma-mapping.h:588:3: error: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t {aka unsigned int}' [-Werror=format=]
      "%s %s: driver maps %lu bytes from %s area\n",
      ^
   include/asm-generic/bug.h:92:17: note: in definition of macro '__WARN_printf'
      __warn_printk(arg);     \
                    ^~~
   include/asm-generic/bug.h:155:3: note: in expansion of macro 'WARN'
      WARN(1, format);    \
      ^~~~
   include/linux/dma-mapping.h:587:2: note: in expansion of macro 'WARN_ONCE'
     WARN_ONCE(is_vmalloc_addr(ptr) || !virt_addr_valid(ptr),
     ^~~~~~~~~
   cc1: all warnings being treated as errors

vim +588 include/linux/dma-mapping.h

   582	
   583	static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
   584			size_t size, enum dma_data_direction dir, unsigned long attrs)
   585	{
   586		/* DMA must never operate on stack or other remappable places. */
   587		WARN_ONCE(is_vmalloc_addr(ptr) || !virt_addr_valid(ptr),
 > 588			"%s %s: driver maps %lu bytes from %s area\n",
   589			dev ? dev_driver_string(dev) : "unknown driver",
   590			dev ? dev_name(dev) : "unknown device", size,
   591			is_vmalloc_addr(ptr) ? "vmalloc" : "invalid");
   592	
   593		return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr),
   594				size, dir, attrs);
   595	}
   596	

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