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From: Hannes Reinecke <hare@suse.de>
To: Bart Van Assche <Bart.VanAssche@wdc.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "hch@lst.de" <hch@lst.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"keith.busch@intel.com" <keith.busch@intel.com>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"hare@suse.com" <hare@suse.com>,
	"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH 2/5] nvme: register ns_id attributes as default sysfs groups
Date: Tue, 14 Aug 2018 17:39:20 +0200	[thread overview]
Message-ID: <e4c9ba55-ad92-dcb2-1126-38e5ea4c0a13@suse.de> (raw)
In-Reply-To: <5a4aab8b5f509d8090ad10107b01d11285fe1528.camel@wdc.com>

On 08/14/2018 05:20 PM, Bart Van Assche wrote:
> On Tue, 2018-08-14 at 09:33 +0200, Hannes Reinecke wrote:
>> +const struct attribute_group *nvme_ns_id_attr_groups[] = {
>> +	&nvme_ns_id_attr_group,
>> +	NULL, /* Will be filled in by lightnvm if present */
>> +	NULL,
>> +};
> [ ... ]
>> -void nvme_nvm_unregister_sysfs(struct nvme_ns *ns)
>> -{
>> -	struct nvm_dev *ndev = ns->ndev;
>> -	struct nvm_geo *geo = &ndev->geo;
>> +		return;
>>  
>>  	switch (geo->major_ver_id) {
>>  	case 1:
>> -		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
>> -					&nvm_dev_attr_group_12);
>> +		nvme_ns_id_attr_groups[1] = &nvm_dev_attr_group_12;
>>  		break;
>>  	case 2:
>> -		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
>> -					&nvm_dev_attr_group_20);
>> +		nvme_ns_id_attr_groups[1] = &nvm_dev_attr_group_20;
> 
> This patch introduces a really ugly dependency between the NVMe core code and
> the lightnvm code, namely that the lightnvm code has to know at which position
> in the nvme_ns_id_attr_groups it can fill in its attribute group pointer. Have
> you considered to make nvme_nvm_register_sysfs() return an attribute group
> pointer such that the nvme_ns_id_attr_groups can be changed from a global into
> a static array?
> 
Wouldn't help much, as the 'nvme_ns_id_attr_groups' needs to be a global
pointer anyway as it's references from drivers/nvme/host/core.c and
drivers/nvme/host/multipath.c.

While I have considered having nvme_nvm_register_sysfs() returning a
pointer I would then have to remove the 'static' declaration from the
nvm_dev_attr_group_12/20.
Which I didn't really like, either.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

  reply	other threads:[~2018-08-14 15:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-14  7:33 [PATCHv2 0/5] genhd: register default groups with device_add_disk() Hannes Reinecke
2018-08-14  7:33 ` [PATCH 1/5] block: genhd: add 'groups' argument to device_add_disk Hannes Reinecke
2018-08-14 15:17   ` Bart Van Assche
2018-08-14  7:33 ` [PATCH 2/5] nvme: register ns_id attributes as default sysfs groups Hannes Reinecke
2018-08-14  9:03   ` Javier González
2018-08-14  9:59   ` Matias Bjørling
2018-08-14 15:20   ` Bart Van Assche
2018-08-14 15:39     ` Hannes Reinecke [this message]
2018-08-14 15:44       ` Bart Van Assche
2018-08-17  7:00         ` hch
2018-08-17  7:53           ` Hannes Reinecke
2018-08-17 20:04           ` Bart Van Assche
2018-08-17 22:47             ` Sagi Grimberg
2018-08-20  6:34             ` Hannes Reinecke
2018-08-14 21:53   ` kbuild test robot
2018-08-14 21:53   ` [RFC PATCH] nvme: nvme_ns_id_attr_group can be static kbuild test robot
2018-08-17  6:55   ` [PATCH 2/5] nvme: register ns_id attributes as default sysfs groups Christoph Hellwig
2018-08-14  7:33 ` [PATCH 3/5] aoe: use device_add_disk_with_groups() Hannes Reinecke
2018-08-14 15:21   ` Bart Van Assche
2018-08-17  6:53   ` Christoph Hellwig
2018-08-14  7:33 ` [PATCH 4/5] zram: register default groups with device_add_disk() Hannes Reinecke
2018-08-14 15:23   ` Bart Van Assche
2018-08-14  7:33 ` [PATCH 5/5] virtio-blk: modernize sysfs attribute creation Hannes Reinecke
2018-08-14 15:24   ` Bart Van Assche

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