Messages in this thread | | | Subject | Re: [PATCH -next 2/3] md/raid10: convert resync_lock to use seqlock | From | Yu Kuai <> | Date | Sat, 3 Sep 2022 14:07:03 +0800 |
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Hi,
在 2022/09/03 1:03, Logan Gunthorpe 写道: > > > > On 2022-09-02 02:14, Yu Kuai wrote: >> Can you try the following patch? I'm running mdadm tests myself and I >> didn't see any problems yet. > > Yes, that patch seems to fix the issue. > > However, may I suggest we do this without trying to introduce new > helpers into wait.h? I suspect that could result in a fair amount of > bike shedding and delay. wait_event_cmd() is often used in situations > where a specific lock type doesn't have a helper.
Yes, that sounds good. > > My stab at it is in a diff below which also fixes the bug. > > I'd also recommend somebody clean up that nasty condition in > wait_barrier(). Put it into an appropriately named function > with some comments. As is, it is pretty much unreadable.
Now we're at it, I can take a look.
Thanks, Kuai > > Logan > > -- > > > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c > index 0e3229ee1ebc..ae297bc870bd 100644 > --- a/drivers/md/raid10.c > +++ b/drivers/md/raid10.c > @@ -934,22 +934,26 @@ static void flush_pending_writes(struct r10conf *conf) > * lower_barrier when the particular background IO completes. > */ > > +#define wait_event_barrier_cmd(conf, cond, cmd) \ > + wait_event_cmd((conf)->wait_barrier, cond, \ > + write_sequnlock_irq(&(conf)->resync_lock); cmd, \ > + write_seqlock_irq(&(conf)->resync_lock)) > +#define wait_event_barrier(conf, cond) wait_event_barrier_cmd(conf, cond, ) > + > static void raise_barrier(struct r10conf *conf, int force) > { > write_seqlock_irq(&conf->resync_lock); > BUG_ON(force && !conf->barrier); > > /* Wait until no block IO is waiting (unless 'force') */ > - wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, > - conf->resync_lock.lock); > + wait_event_barrier(conf, force || !conf->nr_waiting); > > /* block any new IO from starting */ > WRITE_ONCE(conf->barrier, conf->barrier + 1); > > /* Now wait for all pending IO to complete */ > - wait_event_lock_irq(conf->wait_barrier, > - !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH, > - conf->resync_lock.lock); > + wait_event_barrier(conf, !atomic_read(&conf->nr_pending) && > + conf->barrier < RESYNC_DEPTH); > > write_sequnlock_irq(&conf->resync_lock); > } > @@ -1007,20 +1011,19 @@ static bool wait_barrier(struct r10conf *conf, bool nowait) > ret = false; > } else { > raid10_log(conf->mddev, "wait barrier"); > - wait_event_lock_irq(conf->wait_barrier, > - !conf->barrier || > - (atomic_read(&conf->nr_pending) && > - bio_list && > - (!bio_list_empty(&bio_list[0]) || > - !bio_list_empty(&bio_list[1]))) || > + wait_event_barrier(conf, > + !conf->barrier || > + (atomic_read(&conf->nr_pending) && > + bio_list && > + (!bio_list_empty(&bio_list[0]) || > + !bio_list_empty(&bio_list[1]))) || > /* move on if recovery thread is > * blocked by us > */ > - (conf->mddev->thread->tsk == current && > - test_bit(MD_RECOVERY_RUNNING, > - &conf->mddev->recovery) && > - conf->nr_queued > 0), > - conf->resync_lock.lock); > + (conf->mddev->thread->tsk == current && > + test_bit(MD_RECOVERY_RUNNING, > + &conf->mddev->recovery) && > + conf->nr_queued > 0)); > } > conf->nr_waiting--; > if (!conf->nr_waiting) > @@ -1058,10 +1061,9 @@ static void freeze_array(struct r10conf *conf, int extra) > conf->array_freeze_pending++; > WRITE_ONCE(conf->barrier, conf->barrier + 1); > conf->nr_waiting++; > - wait_event_lock_irq_cmd(conf->wait_barrier, > - atomic_read(&conf->nr_pending) == conf->nr_queued+extra, > - conf->resync_lock.lock, > - flush_pending_writes(conf)); > + wait_event_barrier_cmd(conf, > + atomic_read(&conf->nr_pending) == conf->nr_queued+extra, > + flush_pending_writes(conf)); > > conf->array_freeze_pending--; > write_sequnlock_irq(&conf->resync_lock); > . >
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