[rppt:kho/v4 10/13] kernel/kexec_handover.c:104: warning: Function parameter or struct member 'mem' not described in 'kho_return_mem'

[rppt:kho/v4 10/13] kernel/kexec_handover.c:104: warning: Function parameter or struct member 'mem' not described in 'kho_return_mem'

[kernel test robot]

Hi Alexander,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git kho/v4
head:   a75b813f58b0bc19b2c4b06bd62afc87f02dcb43
commit: 4a0ee0e000d8043b5fea97eb1716f4eda837f9b6 [10/13] arm64: Add KHO support
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20250205/202502051237.fgLGQZuN-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250205/202502051237.fgLGQZuN-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/202502051237.fgLGQZuN-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/kexec_handover.c:104: warning: Function parameter or struct member 'mem' not described in 'kho_return_mem'
>> kernel/kexec_handover.c:142: warning: Function parameter or struct member 'mem' not described in 'kho_claim_mem'


vim +104 kernel/kexec_handover.c

076599f0959a3c Alexander Graf 2024-01-17   94  
076599f0959a3c Alexander Graf 2024-01-17   95  /**
076599f0959a3c Alexander Graf 2024-01-17   96   * kho_return_mem - Notify the kernel that initially reserved memory is no
076599f0959a3c Alexander Graf 2024-01-17   97   * longer needed.
076599f0959a3c Alexander Graf 2024-01-17   98   * @mem - memory range that was preserved during kexec handover
076599f0959a3c Alexander Graf 2024-01-17   99   *
076599f0959a3c Alexander Graf 2024-01-17  100   * When the last consumer of a page returns their memory, kho returns the page
076599f0959a3c Alexander Graf 2024-01-17  101   * to the buddy allocator as free page.
076599f0959a3c Alexander Graf 2024-01-17  102   */
076599f0959a3c Alexander Graf 2024-01-17  103  void kho_return_mem(const struct kho_mem *mem)
076599f0959a3c Alexander Graf 2024-01-17 @104  {
076599f0959a3c Alexander Graf 2024-01-17  105  	uint64_t start_pfn, end_pfn, pfn;
076599f0959a3c Alexander Graf 2024-01-17  106  
076599f0959a3c Alexander Graf 2024-01-17  107  	start_pfn = PFN_DOWN(mem->addr);
076599f0959a3c Alexander Graf 2024-01-17  108  	end_pfn = PFN_UP(mem->addr + mem->size);
076599f0959a3c Alexander Graf 2024-01-17  109  
076599f0959a3c Alexander Graf 2024-01-17  110  	for (pfn = start_pfn; pfn < end_pfn; pfn++)
076599f0959a3c Alexander Graf 2024-01-17  111  		kho_return_pfn(pfn);
076599f0959a3c Alexander Graf 2024-01-17  112  }
076599f0959a3c Alexander Graf 2024-01-17  113  EXPORT_SYMBOL_GPL(kho_return_mem);
076599f0959a3c Alexander Graf 2024-01-17  114  
076599f0959a3c Alexander Graf 2024-01-17  115  static int kho_claim_pfn(ulong pfn)
076599f0959a3c Alexander Graf 2024-01-17  116  {
076599f0959a3c Alexander Graf 2024-01-17  117  	struct page *page = pfn_to_online_page(pfn);
076599f0959a3c Alexander Graf 2024-01-17  118  
076599f0959a3c Alexander Graf 2024-01-17  119  	if (!page)
076599f0959a3c Alexander Graf 2024-01-17  120  		return -ENOMEM;
076599f0959a3c Alexander Graf 2024-01-17  121  
076599f0959a3c Alexander Graf 2024-01-17  122  	/* almost as free_reserved_page(), just don't free the page */
076599f0959a3c Alexander Graf 2024-01-17  123  	ClearPageReserved(page);
076599f0959a3c Alexander Graf 2024-01-17  124  	init_page_count(page);
076599f0959a3c Alexander Graf 2024-01-17  125  	adjust_managed_page_count(page, 1);
076599f0959a3c Alexander Graf 2024-01-17  126  
076599f0959a3c Alexander Graf 2024-01-17  127  	return 0;
076599f0959a3c Alexander Graf 2024-01-17  128  }
076599f0959a3c Alexander Graf 2024-01-17  129  
076599f0959a3c Alexander Graf 2024-01-17  130  /**
076599f0959a3c Alexander Graf 2024-01-17  131   * kho_claim_mem - Notify the kernel that a handed over memory range is now
076599f0959a3c Alexander Graf 2024-01-17  132   * in use
076599f0959a3c Alexander Graf 2024-01-17  133   * @mem - memory range that was preserved during kexec handover
076599f0959a3c Alexander Graf 2024-01-17  134   *
076599f0959a3c Alexander Graf 2024-01-17  135   * A kernel subsystem preserved that range during handover and it is going
076599f0959a3c Alexander Graf 2024-01-17  136   * to reuse this range after kexec. The pages in the range are treated as
076599f0959a3c Alexander Graf 2024-01-17  137   * allocated, but not %PG_reserved.
076599f0959a3c Alexander Graf 2024-01-17  138   *
076599f0959a3c Alexander Graf 2024-01-17  139   * Return: virtual address of the preserved memory range
076599f0959a3c Alexander Graf 2024-01-17  140   */
076599f0959a3c Alexander Graf 2024-01-17  141  void *kho_claim_mem(const struct kho_mem *mem)
076599f0959a3c Alexander Graf 2024-01-17 @142  {
076599f0959a3c Alexander Graf 2024-01-17  143  	u64 start_pfn, end_pfn, pfn;
076599f0959a3c Alexander Graf 2024-01-17  144  	void *va = __va(mem->addr);
076599f0959a3c Alexander Graf 2024-01-17  145  
076599f0959a3c Alexander Graf 2024-01-17  146  	start_pfn = PFN_DOWN(mem->addr);
076599f0959a3c Alexander Graf 2024-01-17  147  	end_pfn = PFN_UP(mem->addr + mem->size);
076599f0959a3c Alexander Graf 2024-01-17  148  
076599f0959a3c Alexander Graf 2024-01-17  149  	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
076599f0959a3c Alexander Graf 2024-01-17  150  		int err = kho_claim_pfn(pfn);
076599f0959a3c Alexander Graf 2024-01-17  151  
076599f0959a3c Alexander Graf 2024-01-17  152  		if (err)
076599f0959a3c Alexander Graf 2024-01-17  153  			return NULL;
076599f0959a3c Alexander Graf 2024-01-17  154  	}
076599f0959a3c Alexander Graf 2024-01-17  155  
076599f0959a3c Alexander Graf 2024-01-17  156  	return va;
076599f0959a3c Alexander Graf 2024-01-17  157  }
076599f0959a3c Alexander Graf 2024-01-17  158  EXPORT_SYMBOL_GPL(kho_claim_mem);
076599f0959a3c Alexander Graf 2024-01-17  159  

:::::: The code at line 104 was first introduced by commit
:::::: 076599f0959a3cd16a8d2a95e552f6f83607ef9a kexec: Add KHO parsing support

:::::: TO: Alexander Graf <graf@amazon.com>
:::::: CC: Mike Rapoport <rppt@kernel.org>

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