Re: [PATCH v7 01/12] mtd: core: always create master device

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: "Usyskin, Alexander" <alexander.usyskin@intel.com>
Cc: "Richard Weinberger" <richard@nod.at>,
	"Vignesh Raghavendra" <vigneshr@ti.com>,
	"De Marchi, Lucas" <lucas.demarchi@intel.com>,
	"Thomas Hellström" <thomas.hellstrom@linux.intel.com>,
	"Vivi, Rodrigo" <rodrigo.vivi@intel.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Tvrtko Ursulin" <tursulin@ursulin.net>,
	"Poosa, Karthik" <karthik.poosa@intel.com>,
	"Abliyev, Reuven" <reuven.abliyev@intel.com>,
	"Weil, Oren jer" <oren.jer.weil@intel.com>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 01/12] mtd: core: always create master device
Date: Wed, 09 Apr 2025 11:59:57 +0200	[thread overview]
Message-ID: <87zfgpejtu.fsf@bootlin.com> (raw)
In-Reply-To: <CY5PR11MB63661044DCB37577A12B5DF9EDAA2@CY5PR11MB6366.namprd11.prod.outlook.com> (Alexander Usyskin's message of "Mon, 7 Apr 2025 12:47:07 +0000")

Hello,

> The mtd_master is completely different class to avoid mtd tree disturbances.
> It is real kernel device object, I'm not sure how we can do 'link to'
> magic here.

Maybe we can add that later if someone needs.

> About MTD_PARTITIONED_MASTER - we can treat it as another partition and 
> create master device plus whole device partition as it's child with all other
> partitions as children of master device.
> For unpartitioned device this mean that we create master device and partition
> regardless of MTD_PARTITIONED_MASTER flag.

I am not sure I follow you. I am proposing to create the mtd_master
device in all cases. I believe this is the future-proof approach. Can
you make this change?

Regarding the hierarchy, I indeed agree with what you propose:
mtd_master parent of whole partition device (if any) parent of
partitions.

Thanks,
Miquèl