Re-checking the faulty flag here brings no value.
The comment about "risk" refers to the risk that the device could
be in the process of being removed by ->hot_remove_disk().
However providing that the ->nr_pending count is incremented inside
an rcu_read_locked() region, there is no risk of that happening.
This is because the rdev pointer (in the personalities array) is set
to NULL before synchronize_rcu(), and ->nr_pending is tested
afterwards. If the rcu_read_locked region happens before the
synchronize_rcu(), the test will see that nr_pending has been incremented.
If it happens afterwards, the rdev pointer will be NULL so there is nothing
to increment.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
if (!rdev)
goto retry;
atomic_inc(&rdev->nr_pending);
- if (test_bit(Faulty, &rdev->flags)) {
- /* cannot risk returning a device that failed
- * before we inc'ed nr_pending
- */
- rdev_dec_pending(rdev, conf->mddev);
- goto retry;
- }
sectors = best_good_sectors;
if (conf->mirrors[best_disk].next_seq_sect != this_sector)
raid10_find_phys(conf, r10_bio);
rcu_read_lock();
-retry:
sectors = r10_bio->sectors;
best_slot = -1;
best_rdev = NULL;
if (slot >= 0) {
atomic_inc(&rdev->nr_pending);
- if (test_bit(Faulty, &rdev->flags)) {
- /* Cannot risk returning a device that failed
- * before we inc'ed nr_pending
- */
- rdev_dec_pending(rdev, conf->mddev);
- goto retry;
- }
r10_bio->read_slot = slot;
} else
rdev = NULL;