From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
Keith Busch <keith.busch@wdc.com>,
Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 2/3] nvme: add 'queue_if_no_path' semantics
Date: Mon, 5 Oct 2020 13:29:16 +0200 [thread overview]
Message-ID: <20201005112916.GB26872@lst.de> (raw)
In-Reply-To: <20201005094256.49358-3-hare@suse.de>
On Mon, Oct 05, 2020 at 11:42:55AM +0200, Hannes Reinecke wrote:
> Instead of reverting the handling of the 'last' path for all
> setups we should be restricting it to the non-fabrics case.
> So add a 'queue_if_no_path' flag which will switch to the
> current behaviour; disabling this flag will revert to the
> original (pre-fabrics) behaviour.
> And set this flag per default for fabrics.
>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
> drivers/nvme/host/core.c | 7 ++++++-
> drivers/nvme/host/multipath.c | 4 ++++
> drivers/nvme/host/nvme.h | 1 +
> 3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index af950d58c562..79b88b4c448f 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -474,8 +474,11 @@ static void nvme_free_ns_head(struct kref *ref)
> struct nvme_ns_head *head =
> container_of(ref, struct nvme_ns_head, ref);
>
> - if (head->disk)
> + if (head->disk) {
> + if (test_bit(NVME_NSHEAD_QUEUE_IF_NO_PATH, &head->flags))
> + nvme_mpath_remove_disk(head);
> put_disk(head->disk);
> + }
This needs to be in a helper in multipath.c so that it an compile fine
for the non-multipath case.
> @@ -3686,6 +3689,8 @@ static struct nvme_ns_head *nvme_alloc_ns_head(struct nvme_ctrl *ctrl,
> head->subsys = ctrl->subsys;
> head->ns_id = nsid;
> head->ids = *ids;
> + if (ctrl->ops->flags & NVME_F_FABRICS)
> + set_bit(NVME_NSHEAD_QUEUE_IF_NO_PATH, &head->flags);
This needs a comment at very least. In fact I'm not sure we should
mess with defaults here.
How will this bit get set for the non-fabrics case?
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next prev parent reply other threads:[~2020-10-05 11:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 9:42 [RFC PATCHv2 0/3] nvme: queue_if_no_path functionality Hannes Reinecke
2020-10-05 9:42 ` [PATCH 1/3] nvme-mpath: delete disk after last connection Hannes Reinecke
2020-10-05 11:27 ` Christoph Hellwig
2020-10-05 9:42 ` [PATCH 2/3] nvme: add 'queue_if_no_path' semantics Hannes Reinecke
2020-10-05 11:29 ` Christoph Hellwig [this message]
2020-10-05 9:42 ` [PATCH 3/3] nvme: add 'queue_if_no_path' sysfs attribute Hannes Reinecke
2020-10-05 11:31 ` Christoph Hellwig
2020-10-05 11:38 ` Christoph Hellwig
2020-10-05 11:56 ` Hannes Reinecke
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