[ This code is half a decade old so probably removing the dead code is
fine? - dan ]
Hello Mikulas Patocka,
The patch fd2ed4d25270: "dm: add statistics support" from Aug 16,
2013, leads to the following static checker warning:
drivers/md/dm-stats.c:371 dm_stats_create()
warn: dead code because of 's->id == ((~0 >> 1))' and 'tmp_s->id < s->id'
drivers/md/dm-stats.c
361 mutex_lock(&stats->mutex);
362 s->id = 0;
363 list_for_each(l, &stats->list) {
364 tmp_s = container_of(l, struct dm_stat, list_entry);
365 if (WARN_ON(tmp_s->id < s->id)) {
^^^^^^^^^^^^^^^^^
This condition means that s->id can't be INT_MAX.
366 r = -EINVAL;
367 goto out_unlock_resume;
368 }
369 if (tmp_s->id > s->id)
370 break;
371 if (unlikely(s->id == INT_MAX)) {
^^^^^^^^^^^^^^^^
So we can probably remove this dead code? Was something else intended?
372 r = -ENFILE;
373 goto out_unlock_resume;
374 }
375 s->id++;
376 }
377 ret_id = s->id;
378 list_add_tail_rcu(&s->list_entry, l);
379 mutex_unlock(&stats->mutex);
380
381 resume_callback(md);
382
383 return ret_id;
384
385 out_unlock_resume:
386 mutex_unlock(&stats->mutex);
387 resume_callback(md);
388 out:
389 dm_stat_free(&s->rcu_head);
390 return r;
391 }
regards,
dan carpenter
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