Re: [PATCH v3 2/3] dma-mapping: replace zone_dma_bits by zone_dma_limit

[kernel test robot <lkp@xxxxxxxxx>]

Hi Baruch,

kernel test robot noticed the following build warnings:

[auto build test WARNING on arm64/for-next/core]
[also build test WARNING on powerpc/next powerpc/fixes s390/features linus/master v6.11-rc1 next-20240729]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Baruch-Siach/dma-mapping-improve-DMA-zone-selection/20240729-211018
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
patch link:    https://lore.kernel.org/r/053fa4806a2c63efcde80caca473a8b670a2701c.1722249878.git.baruch%40tkos.co.il
patch subject: [PATCH v3 2/3] dma-mapping: replace zone_dma_bits by zone_dma_limit
config: arm-allnoconfig (https://download.01.org/0day-ci/archive/20240730/202407300338.oaUo6jtB-lkp@xxxxxxxxx/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project ccae7b461be339e717d02f99ac857cf0bc7d17fc)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240730/202407300338.oaUo6jtB-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407300338.oaUo6jtB-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

   In file included from kernel/dma/direct.c:7:
   In file included from include/linux/memblock.h:12:
   In file included from include/linux/mm.h:2253:
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> kernel/dma/direct.c:23:46: warning: implicit conversion from 'unsigned long long' to 'phys_addr_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Wconstant-conversion]
      23 | phys_addr_t zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
         |             ~~~~~~~~~~~~~~                   ^~~~~~~~~~~~~~~~
   include/linux/dma-mapping.h:77:40: note: expanded from macro 'DMA_BIT_MASK'
      77 | #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
         |                                        ^~~~~
   2 warnings generated.


vim +23 kernel/dma/direct.c

   > 7	#include <linux/memblock.h>
     8	#include <linux/export.h>
     9	#include <linux/mm.h>
    10	#include <linux/dma-map-ops.h>
    11	#include <linux/scatterlist.h>
    12	#include <linux/pfn.h>
    13	#include <linux/vmalloc.h>
    14	#include <linux/set_memory.h>
    15	#include <linux/slab.h>
    16	#include "direct.h"
    17	
    18	/*
    19	 * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use
    20	 * it for entirely different regions. In that case the arch code needs to
    21	 * override the variable below for dma-direct to work properly.
    22	 */
  > 23	phys_addr_t zone_dma_limit __ro_after_init = DMA_BIT_MASK(24);
    24	

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