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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: simplify gendisk lookup and remove struct block_device aliases v3
Date: Thu,  3 Sep 2020 10:01:00 +0200	[thread overview]
Message-ID: <20200903080119.441674-1-hch@lst.de> (raw)

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 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

Diffstat:
 b/block/genhd.c           |  183 +++++++--------
 b/drivers/base/Makefile   |    2 
 b/drivers/block/amiflop.c |   98 ++++----
 b/drivers/block/ataflop.c |  135 +++++++----
 b/drivers/block/brd.c     |   39 ---
 b/drivers/block/floppy.c  |  154 ++++++++----
 b/drivers/block/loop.c    |   30 --
 b/drivers/block/swim.c    |   17 -
 b/drivers/block/z2ram.c   |  547 ++++++++++++++++++++++------------------------
 b/drivers/ide/ide-probe.c |   66 -----
 b/drivers/ide/ide-tape.c  |    2 
 b/drivers/md/md.c         |   21 -
 b/drivers/scsi/sd.c       |   19 -
 b/fs/char_dev.c           |   94 +++----
 b/fs/dcache.c             |    1 
 b/fs/internal.h           |    5 
 b/include/linux/genhd.h   |   12 -
 b/include/linux/ide.h     |    3 
 drivers/base/map.c        |  154 ------------
 include/linux/kobj_map.h  |   20 -
 20 files changed, 686 insertions(+), 916 deletions(-)

             reply	other threads:[~2020-09-03  8:01 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03  8:01 Christoph Hellwig [this message]
2020-09-03  8:01 ` [PATCH 01/19] char_dev: replace cdev_map with an xarray Christoph Hellwig
2020-09-04 10:16   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 02/19] block: merge drivers/base/map.c into block/genhd.c Christoph Hellwig
2020-09-04 10:17   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 03/19] block: cleanup del_gendisk a bit Christoph Hellwig
2020-09-04 10:18   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 04/19] block: split block_class_lock Christoph Hellwig
2020-09-04 10:19   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 05/19] block: rework requesting modules for unclaimed devices Christoph Hellwig
2020-09-04 10:20   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 06/19] block: add an optional probe callback to major_names Christoph Hellwig
2020-09-04 10:20   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 07/19] ide: remove ide_{,un}register_region Christoph Hellwig
2020-09-03  8:01 ` [PATCH 08/19] swim: don't call blk_register_region Christoph Hellwig
2020-09-04 10:21   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 09/19] sd: use __register_blkdev to avoid a modprobe for an unregistered dev_t Christoph Hellwig
2020-09-04 10:22   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 10/19] brd: use __register_blkdev to allocate devices on demand Christoph Hellwig
2020-09-04 10:23   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 11/19] loop: " Christoph Hellwig
2020-09-04 10:24   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 12/19] md: " Christoph Hellwig
2020-09-04 10:25   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 13/19] ide: switch to __register_blkdev for command set probing Christoph Hellwig
2020-09-04 10:26   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 14/19] floppy: use a separate gendisk for each media format Christoph Hellwig
2020-09-04  9:59   ` Denis Efremov
2020-09-04 10:28   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 15/19] amiflop: use separate gendisks for Amiga vs MS-DOS mode Christoph Hellwig
2020-09-04 10:28   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 16/19] ataflop: use a separate gendisk for each media format Christoph Hellwig
2020-09-03  8:14   ` John Paul Adrian Glaubitz
2020-09-04 10:29   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 17/19] z2ram: reindent Christoph Hellwig
2020-09-04 10:29   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 18/19] z2ram: use separate gendisk for the different modes Christoph Hellwig
2020-09-04 10:30   ` Hannes Reinecke
2020-09-03  8:01 ` [PATCH 19/19] block: switch gendisk lookup to a simple xarray Christoph Hellwig
2020-09-04 10:30   ` Hannes Reinecke

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