Hello Jon Derrick,
The patch 10172f200b67: "md: Fix types in sb writer" from Feb 24,
2023, leads to the following Smatch static checker warning:
drivers/md/md-bitmap.c:265 __write_sb_page()
warn: unsigned 'offset' is never less than zero.
drivers/md/md-bitmap.c
234 static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
235 struct page *page)
236 {
237 struct block_device *bdev;
238 struct mddev *mddev = bitmap->mddev;
239 struct bitmap_storage *store = &bitmap->storage;
240 sector_t offset = mddev->bitmap_info.offset;
^^^^^^^^
offset used to be llof_t which is s64.
241 sector_t ps, sboff, doff;
242 unsigned int size = PAGE_SIZE;
243 unsigned int opt_size = PAGE_SIZE;
244
245 bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
246 if (page->index == store->file_pages - 1) {
247 unsigned int last_page_size = store->bytes & (PAGE_SIZE - 1);
248
249 if (last_page_size == 0)
250 last_page_size = PAGE_SIZE;
251 size = roundup(last_page_size, bdev_logical_block_size(bdev));
252 opt_size = optimal_io_size(bdev, last_page_size, size);
253 }
254
255 ps = page->index * PAGE_SIZE / SECTOR_SIZE;
256 sboff = rdev->sb_start + offset;
257 doff = rdev->data_offset;
258
259 /* Just make sure we aren't corrupting data or metadata */
260 if (mddev->external) {
261 /* Bitmap could be anywhere. */
262 if (sboff + ps > doff &&
263 sboff < (doff + mddev->dev_sectors + PAGE_SIZE / SECTOR_SIZE))
264 return -EINVAL;
--> 265 } else if (offset < 0) {
^^^^^^^^^^
Now that it's a sector_t this is impossible.
266 /* DATA BITMAP METADATA */
267 size = bitmap_io_size(size, opt_size, offset + ps, 0);
268 if (size == 0)
269 /* bitmap runs in to metadata */
270 return -EINVAL;
271
272 if (doff + mddev->dev_sectors > sboff)
273 /* data runs in to bitmap */
274 return -EINVAL;
275 } else if (rdev->sb_start < rdev->data_offset) {
276 /* METADATA BITMAP DATA */
277 size = bitmap_io_size(size, opt_size, sboff + ps, doff);
278 if (size == 0)
279 /* bitmap runs in to data */
280 return -EINVAL;
281 } else {
282 /* DATA METADATA BITMAP - no problems */
283 }
284
285 md_super_write(mddev, rdev, sboff + ps, (int) size, page);
286 return 0;
287 }
regards,
dan carpenter
