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From: Christoph Hellwig <hch@lst.de>
To: Caleb Sander <csander@purestorage.com>
Cc: Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org,
	Uday Shankar <ushankar@purestorage.com>
Subject: Re: [PATCH] nvme: fix (S)RCU protection of nvme_ns_head list (alternate)
Date: Tue, 29 Nov 2022 09:39:05 +0100	[thread overview]
Message-ID: <20221129083905.GA25314@lst.de> (raw)
In-Reply-To: <20221124002432.3715594-1-csander@purestorage.com>

On Wed, Nov 23, 2022 at 05:24:32PM -0700, Caleb Sander wrote:
> +++ b/drivers/nvme/host/multipath.c
> @@ -175,10 +175,12 @@ void nvme_mpath_revalidate_paths(struct nvme_ns *ns)
>  	sector_t capacity = get_capacity(head->disk);
>  	int node;
>  
> +	rcu_read_lock();
>  	list_for_each_entry_rcu(ns, &head->list, siblings) {
>  		if (capacity != get_capacity(ns->disk))
>  			clear_bit(NVME_NS_READY, &ns->flags);
>  	}
> +	rcu_read_unlock();

I can't see how protection iteraction of the same list once with
SRCU and once with RCU can work in practice.


  parent reply	other threads:[~2022-11-29  8:39 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-18 23:27 [PATCH] nvme: fix SRCU protection of nvme_ns_head list Caleb Sander
2022-11-20 11:24 ` Sagi Grimberg
2022-11-21  7:40   ` Christoph Hellwig
2022-11-21  9:43     ` Sagi Grimberg
2022-11-21 14:57       ` Paul E. McKenney
2022-11-21 17:48     ` Caleb Sander
2022-11-21 17:59       ` Paul E. McKenney
2022-11-21 19:58         ` Caleb Sander
2022-11-22  0:25           ` Paul E. McKenney
2022-11-22 10:06           ` Sagi Grimberg
2022-11-22 12:14             ` Christoph Hellwig
2022-11-22 15:08               ` Sagi Grimberg
2022-11-24  0:12                 ` Caleb Sander
2022-11-24  3:08                   ` Chao Leng
2022-11-24 14:17                   ` Sagi Grimberg
2022-12-01 21:27                 ` Caleb Sander
2022-12-01 23:18                   ` Paul E. McKenney
2022-11-24  0:24 ` [PATCH] nvme: fix (S)RCU protection of nvme_ns_head list (alternate) Caleb Sander
2022-11-24 14:19   ` Sagi Grimberg
2022-11-29  8:39   ` Christoph Hellwig [this message]
2022-11-30  8:25     ` Sagi Grimberg
2022-11-30  8:35       ` Christoph Hellwig
2022-11-30  8:40         ` Sagi Grimberg
2022-12-01 21:17           ` Caleb Sander
2022-12-02  1:21             ` Chao Leng

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