[akpm-mm:mm-new 59/142] mm/vmalloc.c:3590:23: warning: unused variable 'start'

[kernel test robot <lkp@intel.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
head:   88cefc306c43b58d9bb65c9e96e284306710d961
commit: 80c453511b6ee1af0e4db83c3db0020215c4eaf0 [59/142] mm/vmalloc: map contiguous pages in batches for vmap() if possible
config: csky-allnoconfig (https://download.01.org/0day-ci/archive/20260629/202606291606.9h8aGniQ-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 16.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260629/202606291606.9h8aGniQ-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202606291606.9h8aGniQ-lkp@intel.com/

All warnings (new ones prefixed by >>):

   mm/vmalloc.c: In function 'vmap_batched':
>> mm/vmalloc.c:3590:23: warning: unused variable 'start' [-Wunused-variable]
    3590 |         unsigned long start = addr, map_addr = addr;
         |                       ^~~~~


vim +/start +3590 mm/vmalloc.c

  3584	
  3585	static int vmap_batched(unsigned long addr, unsigned long end,
  3586			pgprot_t prot, struct page **pages)
  3587	{
  3588		unsigned int count = (end - addr) >> PAGE_SHIFT;
  3589		unsigned int prev_shift = 0, idx = 0;
> 3590		unsigned long start = addr, map_addr = addr;
  3591		int err;
  3592	
  3593		err = kmsan_vmap_pages_range_noflush(addr, end, prot, pages,
  3594							PAGE_SHIFT, GFP_KERNEL);
  3595		if (err)
  3596			goto out;
  3597	
  3598		for (unsigned int i = 0; i < count; ) {
  3599			unsigned int shift = PAGE_SHIFT +
  3600				get_vmap_batch_order(pages, prot, count - i, i);
  3601	
  3602			if (!i)
  3603				prev_shift = shift;
  3604	
  3605			if (shift != prev_shift) {
  3606				err = vmap_pages_range_noflush_walk(map_addr, addr,
  3607						prot, pages + idx, prev_shift);
  3608				if (err)
  3609					goto out;
  3610				prev_shift = shift;
  3611				map_addr = addr;
  3612				idx = i;
  3613			}
  3614	
  3615			/*
  3616			 * Once small pages are encountered, the remaining pages
  3617			 * are likely small as well.
  3618			 */
  3619			if (shift == PAGE_SHIFT)
  3620				break;
  3621	
  3622			addr += 1UL << shift;
  3623			i += 1U << (shift - PAGE_SHIFT);
  3624		}
  3625	
  3626		/* Remaining */
  3627		if (map_addr < end)
  3628			err = vmap_pages_range_noflush_walk(map_addr, end,
  3629					prot, pages + idx, prev_shift);
  3630	
  3631	out:
  3632		flush_cache_vmap(start, end);
  3633		return err;
  3634	}
  3635	

--
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