linux-kernel - Re: [PATCH] PM: hibernate: don't store zero pages in the image file.

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Message-ID: <202301140607.LS1zOH2d-lkp@intel.com>
Date:   Sat, 14 Jan 2023 07:06:08 +0800
From:   kernel test robot <lkp@...el.com>
To:     Brian Geffon <bgeffon@...gle.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     oe-kbuild-all@...ts.linux.dev, Pavel Machek <pavel@....cz>,
        Len Brown <len.brown@...el.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Brian Geffon <bgeffon@...gle.com>
Subject: Re: [PATCH] PM: hibernate: don't store zero pages in the image file.

Hi Brian,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on pavel-leds/for-next]
[also build test WARNING on linus/master v6.2-rc3]
[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/Brian-Geffon/PM-hibernate-don-t-store-zero-pages-in-the-image-file/20230114-033229
base:   git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds.git for-next
patch link:    https://lore.kernel.org/r/20230113193006.1320379-1-bgeffon%40google.com
patch subject: [PATCH] PM: hibernate: don't store zero pages in the image file.
config: mips-allmodconfig
compiler: mips-linux-gcc (GCC) 12.1.0
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/intel-lab-lkp/linux/commit/658520c74070e600d934d02aada9e2b8838248cf
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Brian-Geffon/PM-hibernate-don-t-store-zero-pages-in-the-image-file/20230114-033229
        git checkout 658520c74070e600d934d02aada9e2b8838248cf
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash kernel/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

   kernel/power/snapshot.c: In function 'unpack_orig_pfns':
>> kernel/power/snapshot.c:2307:16: warning: variable 'zero' set but not used [-Wunused-but-set-variable]
    2307 |         int j, zero;
         |                ^~~~


vim +/zero +2307 kernel/power/snapshot.c

  2293	
  2294	/**
  2295	 * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
  2296	 * @bm: Memory bitmap.
  2297	 * @buf: Area of memory containing the PFNs.
  2298	 * @zero_bm: Memory bitmap which will be populated with the PFNs of zero pages.
  2299	 *
  2300	 * For each element of the array pointed to by @buf (1 page at a time), set the
  2301	 * corresponding bit in @bm. If the page was originally populated with only
  2302	 * zeros then a corresponding bit will also be set in @zero_bm.
  2303	 */
  2304	static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm,
  2305			struct memory_bitmap *zero_bm)
  2306	{
> 2307		int j, zero;
  2308		unsigned long decoded_pfn;
  2309	
  2310		for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
  2311			if (unlikely(buf[j] == BM_END_OF_MAP))
  2312				break;
  2313	
  2314			zero = !!(buf[j] & ENCODED_PFN_ZERO_FLAG);
  2315			decoded_pfn = buf[j] & ENCODED_PFN_MASK;
  2316			if (pfn_valid(decoded_pfn) && memory_bm_pfn_present(bm, decoded_pfn)) {
  2317				memory_bm_set_bit(bm, decoded_pfn);
  2318			} else {
  2319				if (!pfn_valid(decoded_pfn))
  2320					pr_err(FW_BUG "Memory map mismatch at 0x%llx after hibernation\n",
  2321					       (unsigned long long)PFN_PHYS(decoded_pfn));
  2322				return -EFAULT;
  2323			}
  2324		}
  2325	
  2326		return 0;
  2327	}
  2328	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

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