Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 11 Nov 2020 08:57:54 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Denis Efremov <efremov@linux.com>,
        "David S. Miller" <davem@davemloft.net>,
        Song Liu <song@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>,
        Finn Thain <fthain@telegraphics.com.au>,
        Michael Schmitz <schmitzmic@gmail.com>,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-ide@vger.kernel.org, linux-raid@vger.kernel.org,
        linux-scsi@vger.kernel.org, linux-m68k@lists.linux-m68k.org
Subject: Re: simplify gendisk lookup and remove struct block_device aliases
 v4
Message-ID: <20201111075754.GA23010@lst.de>
References: <20201029145841.144173-1-hch@lst.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201029145841.144173-1-hch@lst.de>
User-Agent: Mutt/1.5.17 (2007-11-01)
Precedence: bulk

Jens, can you take a look and possibly pick this series up?

On Thu, Oct 29, 2020 at 03:58:23PM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> this series removes the annoying struct block_device aliases, which can
> happen for a bunch of old floppy drivers (and z2ram).  In that case
> multiple struct block device instances for different dev_t's can point
> to the same gendisk, without being partitions.  The cause for that
> is the probe/get callback registered through blk_register_regions.
> 
> This series removes blk_register_region entirely, splitting it it into
> a simple xarray lookup of registered gendisks, and a probe callback
> stored in the major_names array that can be used for modprobe overrides
> or creating devices on demands when no gendisk is found.  The old
> remapping is gone entirely, and instead the 4 remaining drivers just
> register a gendisk for each operating mode.  In case of the two drivers
> that have lots of aliases that is done on-demand using the new probe
> callback, while for the other two I simply register all at probe time
> to keep things simple.
> 
> Note that the m68k drivers are compile tested only.
> 
> Changes since v3:
>  - keep kobj_map for char dev lookup for now, as the testbot found
>    some very strange and unexplained regressions, so I'll get back to
>    this later separately
>  - fix a commit message typo
> 
> Changes since v2:
>  - fix a wrong variable passed to ERR_PTR in the floppy driver
>  - slightly adjust the del_gendisk cleanups to prepare for the next
>    series touching this area
> 
> Changes since v1:
>  - add back a missing kobject_put in the cdev code
>  - improve the xarray delete loops
---end quoted text---