[PATCH v2] block: limit the extract size to align queue limit
kernel test robot
lkp at intel.com
Fri Nov 10 02:59:19 PST 2023
Hi,
kernel test robot noticed the following build warnings:
[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on hch-configfs/for-next linus/master v6.6 next-20231110]
[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/ed-tsai-mediatek-com/block-limit-the-extract-size-to-align-queue-limit/20231110-142205
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link: https://lore.kernel.org/r/20231110051950.21972-1-ed.tsai%40mediatek.com
patch subject: [PATCH v2] block: limit the extract size to align queue limit
config: arc-randconfig-002-20231110 (https://download.01.org/0day-ci/archive/20231110/202311101853.9N398fyj-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231110/202311101853.9N398fyj-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311101853.9N398fyj-lkp@intel.com/
All warnings (new ones prefixed by >>):
block/bio.c: In function '__bio_iov_iter_get_pages':
>> block/bio.c:1261:29: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
1261 | max - bio->bi_iter.bi_size & (max - 1) : max;
| ~~~~^~~~~~~~~~~~~~~~~~~~~~
vim +1261 block/bio.c
1214
1215 /**
1216 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio
1217 * @bio: bio to add pages to
1218 * @iter: iov iterator describing the region to be mapped
1219 *
1220 * Extracts pages from *iter and appends them to @bio's bvec array. The pages
1221 * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag.
1222 * For a multi-segment *iter, this function only adds pages from the next
1223 * non-empty segment of the iov iterator.
1224 */
1225 static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
1226 {
1227 iov_iter_extraction_t extraction_flags = 0;
1228 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;
1229 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;
1230 struct block_device *bdev = bio->bi_bdev;
1231 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;
1232 struct page **pages = (struct page **)bv;
1233 ssize_t max_extract = UINT_MAX - bio->bi_iter.bi_size;
1234 ssize_t size, left;
1235 unsigned len, i = 0;
1236 size_t offset;
1237 int ret = 0;
1238
1239 /*
1240 * Move page array up in the allocated memory for the bio vecs as far as
1241 * possible so that we can start filling biovecs from the beginning
1242 * without overwriting the temporary page array.
1243 */
1244 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);
1245 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);
1246
1247 if (bdev && blk_queue_pci_p2pdma(bdev->bd_disk->queue))
1248 extraction_flags |= ITER_ALLOW_P2PDMA;
1249
1250 /*
1251 * Each segment in the iov is required to be a block size multiple.
1252 * However, we may not be able to get the entire segment if it spans
1253 * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the
1254 * result to ensure the bio's total size is correct. The remainder of
1255 * the iov data will be picked up in the next bio iteration.
1256 */
1257 if (bdev && bio_op(bio) != REQ_OP_ZONE_APPEND) {
1258 unsigned int max = queue_max_bytes(bdev_get_queue(bdev));
1259
1260 max_extract = bio->bi_iter.bi_size ?
> 1261 max - bio->bi_iter.bi_size & (max - 1) : max;
1262 }
1263 size = iov_iter_extract_pages(iter, &pages, max_extract,
1264 nr_pages, extraction_flags, &offset);
1265 if (unlikely(size <= 0))
1266 return size ? size : -EFAULT;
1267
1268 nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
1269
1270 if (bdev) {
1271 size_t trim = size & (bdev_logical_block_size(bdev) - 1);
1272 iov_iter_revert(iter, trim);
1273 size -= trim;
1274 }
1275
1276 if (unlikely(!size)) {
1277 ret = -EFAULT;
1278 goto out;
1279 }
1280
1281 for (left = size, i = 0; left > 0; left -= len, i++) {
1282 struct page *page = pages[i];
1283
1284 len = min_t(size_t, PAGE_SIZE - offset, left);
1285 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
1286 ret = bio_iov_add_zone_append_page(bio, page, len,
1287 offset);
1288 if (ret)
1289 break;
1290 } else
1291 bio_iov_add_page(bio, page, len, offset);
1292
1293 offset = 0;
1294 }
1295
1296 iov_iter_revert(iter, left);
1297 out:
1298 while (i < nr_pages)
1299 bio_release_page(bio, pages[i++]);
1300
1301 return ret;
1302 }
1303
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
More information about the Linux-mediatek
mailing list