Hi Sergei, Thank you for the patch! Yet something to improve: [auto build test ERROR on lwn/docs-next] [also build test ERROR on linus/master v5.11-rc7 next-20210125] [cannot apply to dm/for-next block/for-next] [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] url: https://github.com/0day-ci/linux/commits/Sergei-Shtepa/block-layer-interp... base: git://git.lwn.net/linux-2.6 docs-next config: x86_64-rhel-8.3 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/2dbb264e739c9f95b90e4ea2a0cdb5d87... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sergei-Shtepa/block-layer-interposer/20210209-223704 git checkout 2dbb264e739c9f95b90e4ea2a0cdb5d874628746 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Note: the linux-review/Sergei-Shtepa/block-layer-interposer/20210209-223704 HEAD a0be3a113742b603fe383ca9a97978f9815a8283 builds fine. It only hurts bisectibility. All errors (new ones prefixed by >>): drivers/md/dm.c: In function 'open_table_device': 1108 | td->dm_dev.non_exclusive = non_exclusive; | ^ drivers/md/dm.c: In function 'dm_get_table_device': 1157 | if ((r = open_table_device(td, dev, md))) { | ^~~~~~~~~~~~~~~~~ drivers/md/dm.c:1079:12: note: declared here 1079 | static int open_table_device(struct table_device *td, dev_t dev, | ^~~~~~~~~~~~~~~~~ vim +1108 drivers/md/dm.c 1075 1076 /* 1077 * Open a table device so we can use it as a map destination. 1078 */ 1079 static int open_table_device(struct table_device *td, dev_t dev, 1080 struct mapped_device *md, bool non_exclusive) 1081 { 1082 struct block_device *bdev; 1083 int ret; 1084 1085 BUG_ON(td->dm_dev.bdev); 1086 1087 if (non_exclusive) 1088 bdev = blkdev_get_by_dev(dev, td->dm_dev.mode, NULL); 1089 else 1090 bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _dm_claim_ptr); 1091 1092 if (IS_ERR(bdev)) { 1093 ret = PTR_ERR(bdev); 1094 if (ret != -EBUSY) 1095 return ret; 1096 } 1097 1098 if (!non_exclusive) { 1099 ret = bd_link_disk_holder(bdev, dm_disk(md)); 1100 if (ret) { 1101 blkdev_put(bdev, td->dm_dev.mode); 1102 return ret; 1103 } 1104 } 1105 1106 td->dm_dev.bdev = bdev; 1107 td->dm_dev.dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 1109 return 0; 1110 } 1111 1112 /* 1113 * Close a table device that we've been using. 1114 */ 1115 static void close_table_device(struct table_device *td, struct mapped_device *md) 1116 { 1117 if (!td->dm_dev.bdev) 1118 return; 1119 1120 bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md)); 1121 blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL); 1122 put_dax(td->dm_dev.dax_dev); 1123 td->dm_dev.bdev = NULL; 1124 td->dm_dev.dax_dev = NULL; 1125 } 1126 1127 static struct table_device *find_table_device(struct list_head *l, dev_t dev, 1128 fmode_t mode) 1129 { 1130 struct table_device *td; 1131 1132 list_for_each_entry(td, l, list) 1133 if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode) 1134 return td; 1135 1136 return NULL; 1137 } 1138 1139 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, 1140 struct dm_dev **result) 1141 { 1142 int r; 1143 struct table_device *td; 1144 1145 mutex_lock(&md->table_devices_lock); 1146 td = find_table_device(&md->table_devices, dev, mode); 1147 if (!td) { 1148 td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id); 1149 if (!td) { 1150 mutex_unlock(&md->table_devices_lock); 1151 return -ENOMEM; 1152 } 1153 1154 td->dm_dev.mode = mode; 1155 td->dm_dev.bdev = NULL; 1156 1158 mutex_unlock(&md->table_devices_lock); 1159 kfree(td); 1160 return r; 1161 } 1162 1163 format_dev_t(td->dm_dev.name, dev); 1164 1165 refcount_set(&td->count, 1); 1166 list_add(&td->list, &md->table_devices); 1167 } else { 1168 refcount_inc(&td->count); 1169 } 1170 mutex_unlock(&md->table_devices_lock); 1171 1172 *result = &td->dm_dev; 1173 return 0; 1174 } 1175 EXPORT_SYMBOL_GPL(dm_get_table_device); 1176 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org