Messages in this thread | | | Date | Tue, 25 Apr 2006 16:07:31 +0800 | From | Coywolf Qi Hunt <> | Subject | Re: [patch 1/2] raid6_end_write_request() spinlock fix |
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On Tue, Apr 25, 2006 at 04:50:10PM +1000, Neil Brown wrote: > On Tuesday April 25, qiyong@fc-cn.com wrote: > > On Tue, Apr 25, 2006 at 03:13:49PM +1000, Neil Brown wrote: > > > On Tuesday April 25, qiyong@fc-cn.com wrote: > > > > Hello, > > > > > > > > Reduce the raid6_end_write_request() spinlock window. > > > > > > Andrew: please don't include these in -mm. This one and the > > > corresponding raid5 are wrong, and I'm not sure yet the unplug_device > > > changes. > > > > I am sure with the unplug_device. Just look follow the path... > > > > What path? There are probably several. If I follow the path, will I > see the same things as you see? Who knows, because you haven't > bothered to tell us what you see.
There are only two places where handle_list is possibly re-filled: __release_stripe() and raidX_activate_delayed(). So raidXd should only wakeup after these two points.
> > > > > Yes. Let's fix the error(). In any case, the current code is broken. (see raid5/6_end_read_request) > > What will I see in raidX_end_read_request. Surely it isn't that hard > to write a few more sentences?
You should see md_error() in raidX_end_read_request isn't in any spinlocks.
> conf->working_disks isn't atomic_t and so decrementing without a > spinlock isn't safe. So lets just leave it all inside a spinlock.
test_and_set_bit(Faulty, &rdev->flags) protects it as well imho. It can be enter only once.
> > Also I have a vague memory that clearing In_sync before Faulty is > important, but I'm not certain of that.
Maybe, but seems not apply here.
> > Remember: the code is there for a reason. It might not be a good > reason, and the code could well be wrong. But it would be worth your > effort trying to find out what the reason is before blithely changing > it (as I discovered recently with a change I suggested to > invalidate_mapping_pages).
Thanks :) -- Coywolf Qi Hunt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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