> 2025年3月8日 18:25，Dan Carpenter <dan.carpenter@xxxxxxxxxx> 写道：
>
> Hello Coly Li,
>
> Commit 3ea3354cb9f0 ("badblocks: improve badblocks_check() for
> multiple ranges handling") from Aug 12, 2023 (linux-next), leads to
> the following Smatch static checker warning:
>
> block/badblocks.c:1251 _badblocks_check()
> warn: unsigned 'sectors' is never less than zero.
>
> block/badblocks.c
> 1186 static int _badblocks_check(struct badblocks *bb, sector_t s, sector_t sectors,
> ^^^^^^^^^^^^^^^^
> sector_t is u64.
Hi Dan,
Thank you for the notice.
>
> 1187 sector_t *first_bad, sector_t *bad_sectors)
> 1188 {
> 1189 int prev = -1, hint = -1, set = 0;
> 1190 struct badblocks_context bad;
> 1191 int unacked_badblocks = 0;
> 1192 int acked_badblocks = 0;
> 1193 u64 *p = bb->page;
> 1194 int len, rv;
> 1195
> 1196 re_check:
> 1197 bad.start = s;
> 1198 bad.len = sectors;
> 1199
> 1200 if (badblocks_empty(bb)) {
> 1201 len = sectors;
> 1202 goto update_sectors;
> 1203 }
> 1204
> 1205 prev = prev_badblocks(bb, &bad, hint);
> 1206
> 1207 /* start after all badblocks */
> 1208 if ((prev >= 0) &&
> 1209 ((prev + 1) >= bb->count) && !overlap_front(bb, prev, &bad)) {
> 1210 len = sectors;
> 1211 goto update_sectors;
> 1212 }
> 1213
> 1214 /* Overlapped with front badblocks record */
> 1215 if ((prev >= 0) && overlap_front(bb, prev, &bad)) {
> 1216 if (BB_ACK(p[prev]))
> 1217 acked_badblocks++;
> 1218 else
> 1219 unacked_badblocks++;
> 1220
> 1221 if (BB_END(p[prev]) >= (s + sectors))
> 1222 len = sectors;
> 1223 else
> 1224 len = BB_END(p[prev]) - s;
> 1225
> 1226 if (set == 0) {
> 1227 *first_bad = BB_OFFSET(p[prev]);
> 1228 *bad_sectors = BB_LEN(p[prev]);
> 1229 set = 1;
> 1230 }
> 1231 goto update_sectors;
> 1232 }
> 1233
> 1234 /* Not front overlap, but behind overlap */
> 1235 if ((prev + 1) < bb->count && overlap_behind(bb, &bad, prev + 1)) {
> 1236 len = BB_OFFSET(p[prev + 1]) - bad.start;
> 1237 hint = prev + 1;
> 1238 goto update_sectors;
> 1239 }
> 1240
> 1241 /* not cover any badblocks range in the table */
> 1242 len = sectors;
> 1243
> 1244 update_sectors:
> 1245 s += len;
> 1246 sectors -= len;
> ^^^^^^^^^^^^^^
> Subtraction.
>
> 1247
> 1248 if (sectors > 0)
> 1249 goto re_check;
> 1250
> --> 1251 WARN_ON(sectors < 0);
> ^^^^^^^^^^^
>
Yes you are right, this is totally unnecessary and no sense. Let me fix it.
Thank you again !
Coly Li
> 1252
> 1253 if (unacked_badblocks > 0)
> 1254 rv = -1;
> 1255 else if (acked_badblocks > 0)
> 1256 rv = 1;
> 1257 else
> 1258 rv = 0;
> 1259
> 1260 return rv;
> 1261 }
>
> regards,
> dan carpenter
>
