Re: [PATCH 06/11] md-bitmap: refactor md_bitmap_init_from_disk

Song Liu
2023-06-16T06:54:05Z

On Thu, Jun 15, 2023 at 3:01 PM kernel test robot <lkp@intel.com> wrote:
>
> Hi Christoph,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on song-md/md-next]
> [also build test WARNING on device-mapper-dm/for-next linus/master v6.4-rc6 next-20230615]
> [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/Christoph-Hellwig/md-bitmap-initialize-variables-at-declaration-time-in-md_bitmap_file_unmap/20230615-154928
> base: git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next
> patch link: https://lore.kernel.org/r/20230615064840.629492-7-hch%40lst.de
> patch subject: [PATCH 06/11] md-bitmap: refactor md_bitmap_init_from_disk
> config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20230616/202306160552.smw0qbmb-lkp@intel.com/config)
> compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a)
> reproduce (this is a W=1 build):
> mkdir -p ~/bin
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> git remote add song-md git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git
> git fetch song-md md-next
> git checkout song-md/md-next
> b4 shazam https://lore.kernel.org/r/20230615064840.629492-7-hch@lst.de
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/md/
>
> 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/202306160552.smw0qbmb-lkp@intel.com/

I fixed this one, and applied the set to md-next.

Thanks,
Song

>
> All warnings (new ones prefixed by >>):
>
> >> drivers/md/md-bitmap.c:1107:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> if (file && i_size_read(file->f_mapping->host) < store->bytes) {
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/md/md-bitmap.c:1198:9: note: uninitialized use occurs here
> return ret;
> ^~~
> drivers/md/md-bitmap.c:1107:2: note: remove the 'if' if its condition is always false
> if (file && i_size_read(file->f_mapping->host) < store->bytes) {
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/md/md-bitmap.c:1090:9: note: initialize the variable 'ret' to silence this warning
> int ret;
> ^
> = 0
> 1 warning generated.
>
>
> vim +1107 drivers/md/md-bitmap.c
>
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1068
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1069 /*
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1070 * Initialize the in-memory bitmap from the on-disk bitmap and set up the memory
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1071 * mapping of the bitmap file.
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1072 *
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1073 * Special case: If there's no bitmap file, or if the bitmap file had been
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1074 * previously kicked from the array, we mark all the bits as 1's in order to
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1075 * cause a full resync.
> 6a07997fc34ac1 drivers/md/bitmap.c NeilBrown 2005-09-09 1076 *
> 6a07997fc34ac1 drivers/md/bitmap.c NeilBrown 2005-09-09 1077 * We ignore all bits for sectors that end earlier than 'start'.
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1078 * This is used when reading an out-of-date bitmap.
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1079 */
> e64e4018d57271 drivers/md/md-bitmap.c Andy Shevchenko 2018-08-01 1080 static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1081 {
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1082 bool outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1083 struct mddev *mddev = bitmap->mddev;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1084 unsigned long chunks = bitmap->counts.chunks;
> 1ec885cdd01a9a drivers/md/bitmap.c NeilBrown 2012-05-22 1085 struct bitmap_storage *store = &bitmap->storage;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1086 struct file *file = store->file;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1087 unsigned long node_offset = 0;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1088 unsigned long bit_cnt = 0;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1089 unsigned long i;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1090 int ret;
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1091
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1092 if (!file && !mddev->bitmap_info.offset) {
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1093 /* No permanent bitmap - fill with '1s'. */
> 1ec885cdd01a9a drivers/md/bitmap.c NeilBrown 2012-05-22 1094 store->filemap = NULL;
> 1ec885cdd01a9a drivers/md/bitmap.c NeilBrown 2012-05-22 1095 store->file_pages = 0;
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1096 for (i = 0; i < chunks ; i++) {
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1097 /* if the disk bit is set, set the memory bit */
> 40cffcc0e8f9f6 drivers/md/bitmap.c NeilBrown 2012-05-22 1098 int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1099 >= start);
> e64e4018d57271 drivers/md/md-bitmap.c Andy Shevchenko 2018-08-01 1100 md_bitmap_set_memory_bits(bitmap,
> 40cffcc0e8f9f6 drivers/md/bitmap.c NeilBrown 2012-05-22 1101 (sector_t)i << bitmap->counts.chunkshift,
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1102 needed);
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1103 }
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1104 return 0;
> ef99bf480de9bd drivers/md/bitmap.c NeilBrown 2012-05-22 1105 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1106
> d1244cb062750b drivers/md/bitmap.c NeilBrown 2012-05-22 @1107 if (file && i_size_read(file->f_mapping->host) < store->bytes) {
> ec0cc226854a79 drivers/md/bitmap.c NeilBrown 2016-11-02 1108 pr_warn("%s: bitmap file too short %lu < %lu\n",
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1109 bmname(bitmap),
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1110 (unsigned long) i_size_read(file->f_mapping->host),
> d1244cb062750b drivers/md/bitmap.c NeilBrown 2012-05-22 1111 store->bytes);
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1112 goto err;
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1113 }
> bc7f77de2cd817 drivers/md/bitmap.c NeilBrown 2005-06-21 1114
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1115 if (mddev_is_clustered(mddev))
> b97e92574c0bf3 drivers/md/bitmap.c Goldwyn Rodrigues 2014-06-06 1116 node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
> b97e92574c0bf3 drivers/md/bitmap.c Goldwyn Rodrigues 2014-06-06 1117
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1118 for (i = 0; i < store->file_pages; i++) {
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1119 struct page *page = store->filemap[i];
> d785a06a0b9d0c drivers/md/bitmap.c NeilBrown 2006-06-26 1120 int count;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1121
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1122 /* unmap the old page, we're done with it */
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1123 if (i == store->file_pages - 1)
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1124 count = store->bytes - i * PAGE_SIZE;
> d785a06a0b9d0c drivers/md/bitmap.c NeilBrown 2006-06-26 1125 else
> d785a06a0b9d0c drivers/md/bitmap.c NeilBrown 2006-06-26 1126 count = PAGE_SIZE;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1127
> 27581e5ae01f77 drivers/md/bitmap.c NeilBrown 2012-05-22 1128 if (file)
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1129 ret = read_file_page(file, i, bitmap, count, page);
> 27581e5ae01f77 drivers/md/bitmap.c NeilBrown 2012-05-22 1130 else
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1131 ret = read_sb_page(mddev, mddev->bitmap_info.offset,
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1132 page, i + node_offset, count);
> 27581e5ae01f77 drivers/md/bitmap.c NeilBrown 2012-05-22 1133 if (ret)
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1134 goto err;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1135 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1136
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1137 if (outofdate) {
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1138 pr_warn("%s: bitmap file is out of date, doing full recovery\n",
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1139 bmname(bitmap));
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1140
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1141 for (i = 0; i < store->file_pages; i++) {
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1142 struct page *page = store->filemap[i];
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1143 unsigned long offset = 0;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1144 void *paddr;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1145
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1146 if (i == 0 && !mddev->bitmap_info.external)
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1147 offset = sizeof(bitmap_super_t);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1148
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1149 /*
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1150 * If the bitmap is out of date, dirty the whole page
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1151 * and write it out
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1152 */
> b2f46e68825648 drivers/md/bitmap.c Cong Wang 2011-11-28 1153 paddr = kmap_atomic(page);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1154 memset(paddr + offset, 0xff, PAGE_SIZE - offset);
> b2f46e68825648 drivers/md/bitmap.c Cong Wang 2011-11-28 1155 kunmap_atomic(paddr);
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1156
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1157 write_page(bitmap, page, 1);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1158 if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags)) {
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1159 ret = -EIO;
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1160 goto err;
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1161 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1162 }
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1163 }
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1164
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1165 for (i = 0; i < chunks; i++) {
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1166 struct page *page = filemap_get_page(&bitmap->storage, i);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1167 unsigned long bit = file_page_offset(&bitmap->storage, i);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1168 void *paddr;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1169 bool was_set;
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1170
> b2f46e68825648 drivers/md/bitmap.c Cong Wang 2011-11-28 1171 paddr = kmap_atomic(page);
> b405fe91e50c60 drivers/md/bitmap.c NeilBrown 2012-05-22 1172 if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1173 was_set = test_bit(bit, paddr);
> bd926c63b7a684 drivers/md/bitmap.c NeilBrown 2005-11-08 1174 else
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1175 was_set = test_bit_le(bit, paddr);
> b2f46e68825648 drivers/md/bitmap.c Cong Wang 2011-11-28 1176 kunmap_atomic(paddr);
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1177
> 5479b6ae3886b9 drivers/md/md-bitmap.c Christoph Hellwig 2023-06-15 1178 if (was_set) {
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1179 /* if the disk bit is set, set the memory bit */
> 40cffcc0e8f9f6 drivers/md/bitmap.c NeilBrown 2012-05-22 1180 int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
> db305e507d5544 drivers/md/bitmap.c NeilBrown 2009-05-07 1181 >= start);
> e64e4018d57271 drivers/md/md-bitmap.c Andy Shevchenko 2018-08-01 1182 md_bitmap_set_memory_bits(bitmap,
> 40cffcc0e8f9f6 drivers/md/bitmap.c NeilBrown 2012-05-22 1183 (sector_t)i << bitmap->counts.chunkshift,
> db305e507d5544 drivers/md/bitmap.c NeilBrown 2009-05-07 1184 needed);
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1185 bit_cnt++;
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1186 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1187 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1188
> ec0cc226854a79 drivers/md/bitmap.c NeilBrown 2016-11-02 1189 pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
> 1ec885cdd01a9a drivers/md/bitmap.c NeilBrown 2012-05-22 1190 bmname(bitmap), store->file_pages,
> d1244cb062750b drivers/md/bitmap.c NeilBrown 2012-05-22 1191 bit_cnt, chunks);
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1192
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1193 return 0;
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1194
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1195 err:
> ec0cc226854a79 drivers/md/bitmap.c NeilBrown 2016-11-02 1196 pr_warn("%s: bitmap initialisation failed: %d\n",
> 4ad1366376bfef drivers/md/bitmap.c NeilBrown 2007-07-17 1197 bmname(bitmap), ret);
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1198 return ret;
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1199 }
> 32a7627cf3a353 drivers/md/bitmap.c NeilBrown 2005-06-21 1200
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki