[android-common:android15-6.6 0/1] drivers/iommu/io-pgtable-arm-common.c:139:5: warning: no previous prototype for '__arm_lpae_map'

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

tree:   https://android.googlesource.com/kernel/common android15-6.6
head:   3b6fab0ff24f7108c71a4d9c12567455cb2a5a81
commit: cf616fc76f2555d91fc88a543badc8a051f749c9 [0/1] BACKPORT: FROMLIST: iommu/io-pgtable-arm: Split the page table driver
config: i386-buildonly-randconfig-2004-20250811 (https://download.01.org/0day-ci/archive/20250811/202508111939.iW8PecqM-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250811/202508111939.iW8PecqM-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/202508111939.iW8PecqM-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/iommu/io-pgtable-arm-common.c:139:5: warning: no previous prototype for '__arm_lpae_map' [-Wmissing-prototypes]
     139 | int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
         |     ^~~~~~~~~~~~~~


vim +/__arm_lpae_map +139 drivers/iommu/io-pgtable-arm-common.c

   138	
 > 139	int __arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
   140			   phys_addr_t paddr, size_t size, size_t pgcount,
   141			   arm_lpae_iopte prot, int lvl, arm_lpae_iopte *ptep,
   142			   gfp_t gfp, size_t *mapped)
   143	{
   144		arm_lpae_iopte *cptep, pte;
   145		size_t block_size = ARM_LPAE_BLOCK_SIZE(lvl, data);
   146		size_t tblsz = ARM_LPAE_GRANULE(data);
   147		struct io_pgtable_cfg *cfg = &data->iop.cfg;
   148		int ret = 0, num_entries, max_entries, map_idx_start;
   149	
   150		/* Find our entry at the current level */
   151		map_idx_start = ARM_LPAE_LVL_IDX(iova, lvl, data);
   152		ptep += map_idx_start;
   153	
   154		/* If we can install a leaf entry at this level, then do so */
   155		if (size == block_size) {
   156			max_entries = ARM_LPAE_PTES_PER_TABLE(data) - map_idx_start;
   157			num_entries = min_t(int, pgcount, max_entries);
   158			ret = arm_lpae_init_pte(data, iova, paddr, prot, lvl, num_entries, ptep);
   159			if (!ret)
   160				*mapped += num_entries * size;
   161	
   162			return ret;
   163		}
   164	
   165		/* We can't allocate tables at the final level */
   166		if (WARN_ON(lvl >= ARM_LPAE_MAX_LEVELS - 1))
   167			return -EINVAL;
   168	
   169		/* Grab a pointer to the next level */
   170		pte = READ_ONCE(*ptep);
   171		if (!pte) {
   172			cptep = __arm_lpae_alloc_pages(tblsz, gfp, cfg);
   173			if (!cptep)
   174				return -ENOMEM;
   175	
   176			pte = arm_lpae_install_table(cptep, ptep, 0, data);
   177			if (pte)
   178				__arm_lpae_free_pages(cptep, tblsz, cfg);
   179		} else if (!cfg->coherent_walk && !(pte & ARM_LPAE_PTE_SW_SYNC)) {
   180			__arm_lpae_sync_pte(ptep, 1, cfg);
   181		}
   182	
   183		if (pte && !iopte_leaf(pte, lvl, data->iop.fmt)) {
   184			cptep = iopte_deref(pte, data);
   185		} else if (pte) {
   186			/* We require an unmap first */
   187			WARN_ON(!selftest_running);
   188			return -EEXIST;
   189		}
   190	
   191		/* Rinse, repeat */
   192		return __arm_lpae_map(data, iova, paddr, size, pgcount, prot, lvl + 1,
   193				      cptep, gfp, mapped);
   194	}
   195	

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