Hi Claire,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.11-rc6 next-20210125]
[cannot apply to swiotlb/linux-next robh/for-next xen-tip/linux-next]
[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/Claire-Chang/Restricted-DMA/20210209-142608
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 61556703b610a104de324e4f061dc6cf7b218b46
config: arm-allyesconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/a766e1949e37b6b82605062e9ef9dd109d2ee940
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Claire-Chang/Restricted-DMA/20210209-142608
        git checkout a766e1949e37b6b82605062e9ef9dd109d2ee940
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 

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

All errors (new ones prefixed by >>):

   In file included from include/asm-generic/memory_model.h:5,
                    from arch/arm/include/asm/memory.h:403,
                    from arch/arm/include/asm/page.h:160,
                    from arch/arm/include/asm/thread_info.h:14,
                    from include/linux/thread_info.h:56,
                    from include/asm-generic/current.h:5,
                    from ./arch/arm/include/generated/asm/current.h:1,
                    from include/linux/sched.h:12,
                    from include/linux/ratelimit.h:6,
                    from include/linux/dev_printk.h:16,
                    from include/linux/device.h:15,
                    from include/linux/dma-mapping.h:7,
                    from include/linux/dma-direct.h:9,
                    from kernel/dma/swiotlb.c:24:
   kernel/dma/swiotlb.c: In function 'rmem_swiotlb_device_init':
>> kernel/dma/swiotlb.c:811:32: error: 'reme' undeclared (first use in this function)
     811 |   unsigned long pfn = PHYS_PFN(reme->base);
         |                                ^~~~
   include/linux/pfn.h:22:39: note: in definition of macro 'PHYS_PFN'
      22 | #define PHYS_PFN(x) ((unsigned long)((x) >> PAGE_SHIFT))
         |                                       ^
   kernel/dma/swiotlb.c:811:32: note: each undeclared identifier is reported only once for each function it appears in
     811 |   unsigned long pfn = PHYS_PFN(reme->base);
         |                                ^~~~
   include/linux/pfn.h:22:39: note: in definition of macro 'PHYS_PFN'
      22 | #define PHYS_PFN(x) ((unsigned long)((x) >> PAGE_SHIFT))
         |                                       ^
   kernel/dma/swiotlb.c:811:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
     811 |   unsigned long pfn = PHYS_PFN(reme->base);
         |   ^~~~~~~~


vim +/reme +811 kernel/dma/swiotlb.c

   791	
   792	#ifdef CONFIG_DMA_RESTRICTED_POOL
   793	static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
   794					    struct device *dev)
   795	{
   796		struct swiotlb *swiotlb = rmem->priv;
   797		int ret;
   798	
   799		if (dev->dev_swiotlb)
   800			return -EBUSY;
   801	
   802		/* Since multiple devices can share the same pool, the private data,
   803		 * swiotlb struct, will be initialized by the first device attached
   804		 * to it.
   805		 */
   806		if (!swiotlb) {
   807			swiotlb = kzalloc(sizeof(*swiotlb), GFP_KERNEL);
   808			if (!swiotlb)
   809				return -ENOMEM;
   810	#ifdef CONFIG_ARM
 > 811			unsigned long pfn = PHYS_PFN(reme->base);
   812	
   813			if (!PageHighMem(pfn_to_page(pfn))) {
   814				ret = -EINVAL;
   815				goto cleanup;
   816			}
   817	#endif /* CONFIG_ARM */
   818	
   819			ret = swiotlb_init_tlb_pool(swiotlb, rmem->base, rmem->size);
   820			if (ret)
   821				goto cleanup;
   822	
   823			rmem->priv = swiotlb;
   824		}
   825	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org