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From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "Jens Axboe" <axboe@kernel.dk>,
	linux-block@vger.kernel.org, "Nilay Shroff" <nilay@linux.ibm.com>,
	"Shinichiro Kawasaki" <shinichiro.kawasaki@wdc.com>,
	"Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Subject: Re: [PATCH V3 15/20] block: fail to show/store elevator sysfs attribute if elevator is dying
Date: Wed, 30 Apr 2025 09:07:18 +0800	[thread overview]
Message-ID: <aBF3xsCL6QP5WnR_@fedora> (raw)
In-Reply-To: <20250425183614.GA26393@lst.de>

On Fri, Apr 25, 2025 at 08:36:14PM +0200, Christoph Hellwig wrote:
> On Thu, Apr 24, 2025 at 11:21:38PM +0800, Ming Lei wrote:
> > +	if (test_bit(ELEVATOR_FLAG_DYING, &e->flags))
> > +		error = -ENODEV;
> > +	else
> > +		error = e->type ? entry->show(e, page) : -ENOENT;
> 
> Weird style mix, I'd expand the check for ->type to a proper else
> if here as well.  But how can e->type actually be NULL here to start
> with?

You are right, e->type can't be NULL, which is assigned in its allocation,
never get cleared.


Thanks,
Ming


  reply	other threads:[~2025-04-30  1:07 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-24 15:21 [PATCH V3 00/20] block: unify elevator changing and fix lockdep warning Ming Lei
2025-04-24 15:21 ` [PATCH V3 01/20] block: move blk_mq_add_queue_tag_set() after blk_mq_map_swqueue() Ming Lei
2025-04-24 15:21 ` [PATCH V3 02/20] block: move ELEVATOR_FLAG_DISABLE_WBT a request queue flag Ming Lei
2025-04-25 14:29   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 03/20] block: don't call freeze queue in elevator_switch() and elevator_disable() Ming Lei
2025-04-25 14:29   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 04/20] block: use q->elevator with ->elevator_lock held in elv_iosched_show() Ming Lei
2025-04-25  6:08   ` Hannes Reinecke
2025-04-25 10:53   ` Nilay Shroff
2025-04-25 14:29   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 05/20] block: add two helpers for registering/un-registering sched debugfs Ming Lei
2025-04-24 15:21 ` [PATCH V3 06/20] block: move sched debugfs register into elvevator_register_queue Ming Lei
2025-04-24 15:21 ` [PATCH V3 07/20] block: prevent adding/deleting disk during updating nr_hw_queues Ming Lei
2025-04-25  6:33   ` Hannes Reinecke
2025-04-25 11:37   ` Nilay Shroff
2025-04-25 14:33   ` Christoph Hellwig
2025-04-25 16:46   ` kernel test robot
2025-04-24 15:21 ` [PATCH V3 08/20] block: don't allow to switch elevator if updating nr_hw_queues is in-progress Ming Lei
2025-04-25  6:33   ` Hannes Reinecke
2025-04-25 12:48   ` Nilay Shroff
2025-04-27  2:27     ` Ming Lei
2025-04-28 16:17       ` Nilay Shroff
2025-04-29  2:43         ` Ming Lei
2025-04-29 10:22           ` Nilay Shroff
2025-04-30  0:54             ` Ming Lei
2025-04-24 15:21 ` [PATCH V3 09/20] block: simplify elevator reattachment for updating nr_hw_queues Ming Lei
2025-04-25  6:34   ` Hannes Reinecke
2025-04-25 18:12   ` Christoph Hellwig
2025-04-29  9:51     ` Ming Lei
2025-04-24 15:21 ` [PATCH V3 10/20] block: move blk_unregister_queue() & device_del() after freeze wait Ming Lei
2025-04-25  6:35   ` Hannes Reinecke
2025-04-25 12:50   ` Nilay Shroff
2025-04-25 14:34   ` Christoph Hellwig
2025-04-28 11:51     ` Ming Lei
2025-04-24 15:21 ` [PATCH V3 11/20] block: move queue freezing & elevator_lock into elevator_change() Ming Lei
2025-04-25  6:36   ` Hannes Reinecke
2025-04-25 12:54   ` Nilay Shroff
2025-04-25 14:35   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 12/20] block: add `struct elv_change_ctx` for unifying elevator change Ming Lei
2025-04-25  6:38   ` Hannes Reinecke
2025-04-25 18:23   ` Christoph Hellwig
2025-04-29 15:45     ` Ming Lei
2025-04-24 15:21 ` [PATCH V3 13/20] block: " Ming Lei
2025-04-25  6:39   ` Hannes Reinecke
2025-04-25 13:03   ` Nilay Shroff
2025-04-30  0:46     ` Ming Lei
2025-04-25 18:30   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 14/20] block: pass elevator_queue to elv_register_queue & unregister_queue Ming Lei
2025-04-25  6:40   ` Hannes Reinecke
2025-04-24 15:21 ` [PATCH V3 15/20] block: fail to show/store elevator sysfs attribute if elevator is dying Ming Lei
2025-04-25  6:45   ` Hannes Reinecke
2025-04-25 18:36   ` Christoph Hellwig
2025-04-30  1:07     ` Ming Lei [this message]
2025-04-24 15:21 ` [PATCH V3 16/20] block: move elv_register[unregister]_queue out of elevator_lock Ming Lei
2025-04-25  6:46   ` Hannes Reinecke
2025-04-25 13:05   ` Nilay Shroff
2025-04-25 18:37   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 17/20] block: move debugfs/sysfs register out of freezing queue Ming Lei
2025-04-25  6:47   ` Hannes Reinecke
2025-04-25 18:38   ` Christoph Hellwig
2025-04-28 11:28     ` Ming Lei
2025-04-24 15:21 ` [PATCH V3 18/20] block: remove several ->elevator_lock Ming Lei
2025-04-25  6:48   ` Hannes Reinecke
2025-04-25 18:38   ` Christoph Hellwig
2025-04-24 15:21 ` [PATCH V3 19/20] block: move hctx cpuhp add/del out of queue freezing Ming Lei
2025-04-25  6:49   ` Hannes Reinecke
2025-04-24 15:21 ` [PATCH V3 20/20] block: move wbt_enable_default() out of queue freezing from sched ->exit() Ming Lei
2025-04-25 13:10   ` Nilay Shroff
2025-04-29 10:59   ` Nilay Shroff
2025-04-29 12:00 ` [PATCH V3 00/20] block: unify elevator changing and fix lockdep warning Stefan Haberland
2025-04-29 12:11   ` Ming Lei

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