cleanup and simplify the gendisk flags

cleanup and simplify the gendisk flags

[Christoph Hellwig]

Ho Jens,

the gendisk flags have been a complete mess for a while.  This series
tries to untangle them as much as easily possible.

Diffstat:
 block/bdev.c                       |    5 --
 block/blk.h                        |    1 
 block/genhd.c                      |   41 +++++++----------
 block/ioctl.c                      |   31 ++-----------
 block/partitions/core.c            |   24 ++++------
 drivers/block/amiflop.c            |    1 
 drivers/block/ataflop.c            |    1 
 drivers/block/brd.c                |    1 
 drivers/block/drbd/drbd_main.c     |    1 
 drivers/block/floppy.c             |    1 
 drivers/block/loop.c               |    9 +--
 drivers/block/n64cart.c            |    2 
 drivers/block/null_blk/main.c      |    1 
 drivers/block/paride/pcd.c         |    3 -
 drivers/block/paride/pf.c          |    1 
 drivers/block/pktcdvd.c            |    2 
 drivers/block/ps3vram.c            |    1 
 drivers/block/rbd.c                |    6 --
 drivers/block/sunvdc.c             |   17 +++----
 drivers/block/swim.c               |    1 
 drivers/block/swim3.c              |    2 
 drivers/block/virtio_blk.c         |    1 
 drivers/block/xen-blkback/xenbus.c |    2 
 drivers/block/xen-blkfront.c       |   26 ++++-------
 drivers/block/z2ram.c              |    1 
 drivers/block/zram/zram_drv.c      |    1 
 drivers/cdrom/gdrom.c              |    1 
 drivers/md/dm.c                    |    1 
 drivers/md/md.c                    |    5 --
 drivers/mmc/core/block.c           |    4 -
 drivers/mtd/ubi/block.c            |    1 
 drivers/scsi/sd.c                  |    1 
 drivers/scsi/sr.c                  |    6 +-
 include/linux/genhd.h              |   85 +++++++++----------------------------
 34 files changed, 104 insertions(+), 183 deletions(-)

[PATCH 01/14] block: move GENHD_FL_NATIVE_CAPACITY to disk->state

[Christoph Hellwig]

The flag to indicate an unlocked native capacity is dynamic state,
not a driver capability flag, so move it to disk->state.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c | 15 ++++++---------
 include/linux/genhd.h   |  8 +-------
 2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 334b72ef1d73f..520292fee9339 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -527,18 +527,15 @@ int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
 
 static bool disk_unlock_native_capacity(struct gendisk *disk)
 {
-	const struct block_device_operations *bdops = disk->fops;
-
-	if (bdops->unlock_native_capacity &&
-	    !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
-		printk(KERN_CONT "enabling native capacity\n");
-		bdops->unlock_native_capacity(disk);
-		disk->flags |= GENHD_FL_NATIVE_CAPACITY;
-		return true;
-	} else {
+	if (!disk->fops->unlock_native_capacity ||
+	    test_and_set_bit(GD_NATIVE_CAPACITY, &disk->state)) {
 		printk(KERN_CONT "truncated\n");
 		return false;
 	}
+
+	printk(KERN_CONT "enabling native capacity\n");
+	disk->fops->unlock_native_capacity(disk);
+	return true;
 }
 
 void blk_drop_partitions(struct gendisk *disk)
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 74c4102631130..e490a71e5e9dd 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -60,12 +60,6 @@ struct partition_meta_info {
  * (``BLOCK_EXT_MAJOR``).
  * This affects the maximum number of partitions.
  *
- * ``GENHD_FL_NATIVE_CAPACITY`` (0x0080): based on information in the
- * partition table, the device's capacity has been extended to its
- * native capacity; i.e. the device has hidden capacity used by one
- * of the partitions (this is a flag used so that native capacity is
- * only ever unlocked once).
- *
  * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
  * blocked whenever a writer holds an exclusive lock.
  *
@@ -86,7 +80,6 @@ struct partition_meta_info {
 #define GENHD_FL_CD				0x0008
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
-#define GENHD_FL_NATIVE_CAPACITY		0x0080
 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	0x0100
 #define GENHD_FL_NO_PART_SCAN			0x0200
 #define GENHD_FL_HIDDEN				0x0400
@@ -140,6 +133,7 @@ struct gendisk {
 #define GD_NEED_PART_SCAN		0
 #define GD_READ_ONLY			1
 #define GD_DEAD				2
+#define GD_NATIVE_CAPACITY		3
 
 	struct mutex open_mutex;	/* open/close mutex */
 	unsigned open_partitions;	/* number of open partitions */
-- 
2.30.2

[PATCH 02/14] block: move GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE to disk->event_flags

[Christoph Hellwig]

GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE is all about the event reporting
mechanism, so move it to the event_flags field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bdev.c               | 2 +-
 drivers/block/paride/pcd.c | 2 +-
 drivers/scsi/sr.c          | 5 +++--
 include/linux/genhd.h      | 6 ++----
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index b4dab2fb6a746..cf29c6508bff2 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -837,7 +837,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 		 * used in blkdev_get/put().
 		 */
 		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
-		    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
+		    (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
 			bdev->bd_write_holder = true;
 			unblock_events = false;
 		}
diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index f6b1d63e96e1b..430ee8004a514 100644
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -928,8 +928,8 @@ static int pcd_init_unit(struct pcd_unit *cd, bool autoprobe, int port,
 	disk->minors = 1;
 	strcpy(disk->disk_name, cd->name);	/* umm... */
 	disk->fops = &pcd_bdops;
-	disk->flags = GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
+	disk->event_flags = DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
 
 	if (!pi_init(cd->pi, autoprobe, port, mode, unit, protocol, delay,
 			pcd_buffer, PI_PCD, verbose, cd->name)) {
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 8e4af111c0787..be445dc35f2c7 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -684,9 +684,10 @@ static int sr_probe(struct device *dev)
 	disk->minors = 1;
 	sprintf(disk->disk_name, "sr%d", minor);
 	disk->fops = &sr_bdops;
-	disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
+	disk->flags = GENHD_FL_CD;
 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
-	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT;
+	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT |
+				DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
 
 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
 
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index e490a71e5e9dd..c1136ff3c91fa 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -60,9 +60,6 @@ struct partition_meta_info {
  * (``BLOCK_EXT_MAJOR``).
  * This affects the maximum number of partitions.
  *
- * ``GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE`` (0x0100): event polling is
- * blocked whenever a writer holds an exclusive lock.
- *
  * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
  * Used for loop devices in their default settings and some MMC
  * devices.
@@ -80,7 +77,6 @@ struct partition_meta_info {
 #define GENHD_FL_CD				0x0008
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
-#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE	0x0100
 #define GENHD_FL_NO_PART_SCAN			0x0200
 #define GENHD_FL_HIDDEN				0x0400
 
@@ -94,6 +90,8 @@ enum {
 	DISK_EVENT_FLAG_POLL			= 1 << 0,
 	/* Forward events to udev */
 	DISK_EVENT_FLAG_UEVENT			= 1 << 1,
+	/* Block event polling when open for exclusive write */
+	DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE	= 1 << 2,
 };
 
 struct disk_events;
-- 
2.30.2

[PATCH 03/14] block: remove GENHD_FL_CD

[Christoph Hellwig]

GENHD_FL_CD marks a gendisk as a vaguely CD-ROM like device.
Besides being used internally inside of sunvdc.c an xen-blkfront it
is used by xen-blkback as a hint to claim a device exported to a
guest is a CD-ROM like device.  Just check for disk->cdi instead
which is the right indicator for "real" CD-ROM or DVD drivers.  This
will miss the paravirtualized guest drivers, but those make little
sense to report anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/sunvdc.c             | 17 +++++++++--------
 drivers/block/xen-blkback/xenbus.c |  2 +-
 drivers/block/xen-blkfront.c       | 26 +++++++++++---------------
 drivers/scsi/sr.c                  |  1 -
 include/linux/genhd.h              |  5 -----
 5 files changed, 21 insertions(+), 30 deletions(-)

diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 6f45a53f7cbf5..2157936de623c 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -143,8 +143,8 @@ static int vdc_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 static int vdc_ioctl(struct block_device *bdev, fmode_t mode,
 		     unsigned command, unsigned long argument)
 {
+	struct vdc_port *port = bdev->bd_disk->private_data;
 	int i;
-	struct gendisk *disk;
 
 	switch (command) {
 	case CDROMMULTISESSION:
@@ -155,12 +155,15 @@ static int vdc_ioctl(struct block_device *bdev, fmode_t mode,
 		return 0;
 
 	case CDROM_GET_CAPABILITY:
-		disk = bdev->bd_disk;
-
-		if (bdev->bd_disk && (disk->flags & GENHD_FL_CD))
+		if (!vdc_version_supported(port, 1, 1))
+			return -EINVAL;
+		switch (port->vdisk_mtype) {
+		case VD_MEDIA_TYPE_CD:
+		case VD_MEDIA_TYPE_DVD:
 			return 0;
-		return -EINVAL;
-
+		default:
+			return -EINVAL;
+		}
 	default:
 		pr_debug(PFX "ioctl %08x not supported\n", command);
 		return -EINVAL;
@@ -854,14 +857,12 @@ static int probe_disk(struct vdc_port *port)
 		switch (port->vdisk_mtype) {
 		case VD_MEDIA_TYPE_CD:
 			pr_info(PFX "Virtual CDROM %s\n", port->disk_name);
-			g->flags |= GENHD_FL_CD;
 			g->flags |= GENHD_FL_REMOVABLE;
 			set_disk_ro(g, 1);
 			break;
 
 		case VD_MEDIA_TYPE_DVD:
 			pr_info(PFX "Virtual DVD %s\n", port->disk_name);
-			g->flags |= GENHD_FL_CD;
 			g->flags |= GENHD_FL_REMOVABLE;
 			set_disk_ro(g, 1);
 			break;
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 914587aabca0c..62125fd4af4a7 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -510,7 +510,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	}
 	vbd->size = vbd_sz(vbd);
 
-	if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
+	if (cdrom || disk_to_cdi(vbd->bdev->bd_disk))
 		vbd->type |= VDISK_CDROM;
 	if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
 		vbd->type |= VDISK_REMOVABLE;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8e3983e456f3c..700c765a759a1 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -198,6 +198,7 @@ struct blkfront_info
 	struct gendisk *gd;
 	u16 sector_size;
 	unsigned int physical_sector_size;
+	unsigned long vdisk_info;
 	int vdevice;
 	blkif_vdev_t handle;
 	enum blkif_state connected;
@@ -505,6 +506,7 @@ static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
 static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
 		       unsigned command, unsigned long argument)
 {
+	struct blkfront_info *info = bdev->bd_disk->private_data;
 	int i;
 
 	switch (command) {
@@ -514,9 +516,9 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
 				return -EFAULT;
 		return 0;
 	case CDROM_GET_CAPABILITY:
-		if (bdev->bd_disk->flags & GENHD_FL_CD)
-			return 0;
-		return -EINVAL;
+		if (!(info->vdisk_info & VDISK_CDROM))
+			return -EINVAL;
+		return 0;
 	default:
 		return -EINVAL;
 	}
@@ -1057,9 +1059,8 @@ static char *encode_disk_name(char *ptr, unsigned int n)
 }
 
 static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
-			       struct blkfront_info *info,
-			       u16 vdisk_info, u16 sector_size,
-			       unsigned int physical_sector_size)
+		struct blkfront_info *info, u16 sector_size,
+		unsigned int physical_sector_size)
 {
 	struct gendisk *gd;
 	int nr_minors = 1;
@@ -1157,15 +1158,11 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 
 	xlvbd_flush(info);
 
-	if (vdisk_info & VDISK_READONLY)
+	if (info->vdisk_info & VDISK_READONLY)
 		set_disk_ro(gd, 1);
-
-	if (vdisk_info & VDISK_REMOVABLE)
+	if (info->vdisk_info & VDISK_REMOVABLE)
 		gd->flags |= GENHD_FL_REMOVABLE;
 
-	if (vdisk_info & VDISK_CDROM)
-		gd->flags |= GENHD_FL_CD;
-
 	return 0;
 
 out_free_tag_set:
@@ -2304,7 +2301,6 @@ static void blkfront_connect(struct blkfront_info *info)
 	unsigned long long sectors;
 	unsigned long sector_size;
 	unsigned int physical_sector_size;
-	unsigned int binfo;
 	int err, i;
 	struct blkfront_ring_info *rinfo;
 
@@ -2342,7 +2338,7 @@ static void blkfront_connect(struct blkfront_info *info)
 
 	err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
 			    "sectors", "%llu", &sectors,
-			    "info", "%u", &binfo,
+			    "info", "%u", &info->vdisk_info,
 			    "sector-size", "%lu", &sector_size,
 			    NULL);
 	if (err) {
@@ -2371,7 +2367,7 @@ static void blkfront_connect(struct blkfront_info *info)
 		}
 	}
 
-	err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
+	err = xlvbd_alloc_gendisk(sectors, info, sector_size,
 				  physical_sector_size);
 	if (err) {
 		xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index be445dc35f2c7..6646797a7756e 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -684,7 +684,6 @@ static int sr_probe(struct device *dev)
 	disk->minors = 1;
 	sprintf(disk->disk_name, "sr%d", minor);
 	disk->fops = &sr_bdops;
-	disk->flags = GENHD_FL_CD;
 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
 	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT |
 				DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c1136ff3c91fa..74518c576fbb9 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -46,10 +46,6 @@ struct partition_meta_info {
  * Must not be set for devices which are removed entirely when the
  * media is removed.
  *
- * ``GENHD_FL_CD`` (0x0008): the block device is a CD-ROM-style
- * device.
- * Affects responses to the ``CDROM_GET_CAPABILITY`` ioctl.
- *
  * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
  * partition information in ``/proc/partitions`` or in the output of
  * printk_all_partitions().
@@ -74,7 +70,6 @@ struct partition_meta_info {
 #define GENHD_FL_REMOVABLE			0x0001
 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
-#define GENHD_FL_CD				0x0008
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
 #define GENHD_FL_NO_PART_SCAN			0x0200
-- 
2.30.2

[PATCH 04/14] block: remove a dead check in show_partition

[Christoph Hellwig]

disk_max_parts never returns 0 given that ->minors for devices not using
the extended dev_t must be non-zero, and disk_max_parts always returns
DISK_MAX_PARTS for the latter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index c5392cc24d37e..b1c0f62505bf0 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -814,9 +814,7 @@ static int show_partition(struct seq_file *seqf, void *v)
 	struct block_device *part;
 	unsigned long idx;
 
-	/* Don't show non-partitionable removeable devices or empty devices */
-	if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
-				   (sgp->flags & GENHD_FL_REMOVABLE)))
+	if (!get_capacity(sgp))
 		return 0;
 	if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 		return 0;
-- 
2.30.2

[PATCH 05/14] block: merge disk_scan_partitions and blkdev_reread_part

[Christoph Hellwig]

Unify the functionality that implements a partition rescan for a
gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk.h   |  1 +
 block/genhd.c | 19 ++++++++++++-------
 block/ioctl.c | 31 +++++--------------------------
 3 files changed, 18 insertions(+), 33 deletions(-)

diff --git a/block/blk.h b/block/blk.h
index 296e3010f8d65..cb436dd017ae8 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -449,6 +449,7 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		unsigned int max_sectors, bool *same_page);
 
 struct request_queue *blk_alloc_queue(int node_id);
+int disk_scan_partitions(struct gendisk *disk, fmode_t mode);
 
 int disk_alloc_events(struct gendisk *disk);
 void disk_add_events(struct gendisk *disk);
diff --git a/block/genhd.c b/block/genhd.c
index b1c0f62505bf0..0cf3d30429e14 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -372,17 +372,21 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action)
 }
 EXPORT_SYMBOL_GPL(disk_uevent);
 
-static void disk_scan_partitions(struct gendisk *disk)
+int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 {
 	struct block_device *bdev;
 
-	if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
-		return;
+	if (!disk_part_scan_enabled(disk))
+		return -EINVAL;
+	if (disk->open_partitions)
+		return -EBUSY;
 
 	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
-	if (!IS_ERR(bdev))
-		blkdev_put(bdev, FMODE_READ);
+	bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
+	blkdev_put(bdev, mode);
+	return 0;
 }
 
 /**
@@ -509,7 +513,8 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 			goto out_unregister_bdi;
 
 		bdev_add(disk->part0, ddev->devt);
-		disk_scan_partitions(disk);
+		if (get_capacity(disk))
+			disk_scan_partitions(disk, FMODE_READ);
 
 		/*
 		 * Announce the disk and partitions after all partitions are
diff --git a/block/ioctl.c b/block/ioctl.c
index 0a1d10ac2e1a5..4a86340133e46 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -82,31 +82,6 @@ static int compat_blkpg_ioctl(struct block_device *bdev,
 }
 #endif
 
-static int blkdev_reread_part(struct block_device *bdev, fmode_t mode)
-{
-	struct block_device *tmp;
-
-	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev_is_partition(bdev))
-		return -EINVAL;
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-	if (bdev->bd_disk->open_partitions)
-		return -EBUSY;
-
-	/*
-	 * Reopen the device to revalidate the driver state and force a
-	 * partition rescan.
-	 */
-	mode &= ~FMODE_EXCL;
-	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
-
-	tmp = blkdev_get_by_dev(bdev->bd_dev, mode, NULL);
-	if (IS_ERR(tmp))
-		return PTR_ERR(tmp);
-	blkdev_put(tmp, mode);
-	return 0;
-}
-
 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 		unsigned long arg, unsigned long flags)
 {
@@ -522,7 +497,11 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 		bdev->bd_disk->bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 		return 0;
 	case BLKRRPART:
-		return blkdev_reread_part(bdev, mode);
+		if (!capable(CAP_SYS_ADMIN))
+			return -EACCES;
+		if (bdev_is_partition(bdev))
+			return -EINVAL;
+		return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL);
 	case BLKTRACESTART:
 	case BLKTRACESTOP:
 	case BLKTRACETEARDOWN:
-- 
2.30.2

[PATCH 06/14] block: rename GENHD_FL_NO_PART_SCAN to GENHD_FL_NO_PART

[Christoph Hellwig]

The GENHD_FL_NO_PART_SCAN controls more than just partitions canning,
so rename it to GENHD_FL_NO_PART.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c            |  2 +-
 drivers/block/loop.c     |  8 ++++----
 drivers/block/n64cart.c  |  2 +-
 drivers/mmc/core/block.c |  4 ++--
 include/linux/genhd.h    | 13 ++++++-------
 5 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 0cf3d30429e14..b37925ed1d7e9 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -500,7 +500,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 		 * and don't bother scanning for partitions either.
 		 */
 		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
-		disk->flags |= GENHD_FL_NO_PART_SCAN;
+		disk->flags |= GENHD_FL_NO_PART;
 	} else {
 		ret = bdi_register(disk->bdi, "%u:%u",
 				   disk->major, disk->first_minor);
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a154cab6cd989..7219d98c6fb8a 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1061,7 +1061,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
 	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
 	if (partscan)
-		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
+		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
 
 	loop_global_unlock(lo, is_loop);
 	if (partscan)
@@ -1191,7 +1191,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 	mutex_lock(&lo->lo_mutex);
 	lo->lo_flags = 0;
 	if (!part_shift)
-		lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
+		lo->lo_disk->flags |= GENHD_FL_NO_PART;
 	lo->lo_state = Lo_unbound;
 	mutex_unlock(&lo->lo_mutex);
 
@@ -1301,7 +1301,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 
 	if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
 	     !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
-		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
+		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
 		partscan = true;
 	}
 out_unlock:
@@ -2032,7 +2032,7 @@ static int loop_add(int i)
 	 * userspace tools. Parameters like this in general should be avoided.
 	 */
 	if (!part_shift)
-		disk->flags |= GENHD_FL_NO_PART_SCAN;
+		disk->flags |= GENHD_FL_NO_PART;
 	disk->flags |= GENHD_FL_EXT_DEVT;
 	atomic_set(&lo->lo_refcnt, 0);
 	mutex_init(&lo->lo_mutex);
diff --git a/drivers/block/n64cart.c b/drivers/block/n64cart.c
index 78282f01f5813..4db9a8c244af5 100644
--- a/drivers/block/n64cart.c
+++ b/drivers/block/n64cart.c
@@ -136,7 +136,7 @@ static int __init n64cart_probe(struct platform_device *pdev)
 		goto out;
 
 	disk->first_minor = 0;
-	disk->flags = GENHD_FL_NO_PART_SCAN;
+	disk->flags = GENHD_FL_NO_PART;
 	disk->fops = &n64cart_fops;
 	disk->private_data = &pdev->dev;
 	strcpy(disk->disk_name, "n64cart");
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 90e1bcd03b46c..a71b3512c877a 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2397,8 +2397,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	set_disk_ro(md->disk, md->read_only || default_ro);
 	md->disk->flags = GENHD_FL_EXT_DEVT;
 	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
-		md->disk->flags |= GENHD_FL_NO_PART_SCAN
-				   | GENHD_FL_SUPPRESS_PARTITION_INFO;
+		md->disk->flags |= GENHD_FL_NO_PART |
+				   GENHD_FL_SUPPRESS_PARTITION_INFO;
 
 	/*
 	 * As discussed on lkml, GENHD_FL_REMOVABLE should:
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 74518c576fbb9..0b9be3df94898 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -56,15 +56,15 @@ struct partition_meta_info {
  * (``BLOCK_EXT_MAJOR``).
  * This affects the maximum number of partitions.
  *
- * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
- * Used for loop devices in their default settings and some MMC
- * devices.
+ * ``GENHD_FL_NO_PART`` (0x0200): partition support is disabled.
+ * The kernel will not scan for partitions from add_disk, and users
+ * can't add partitions manually.
  *
  * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
  * doesn't produce events, doesn't appear in sysfs, and doesn't have
  * an associated ``bdev``.
  * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
- * ``GENHD_FL_NO_PART_SCAN``.
+ * ``GENHD_FL_NO_PART``.
  * Used for multipath devices.
  */
 #define GENHD_FL_REMOVABLE			0x0001
@@ -72,7 +72,7 @@ struct partition_meta_info {
 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
 #define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
-#define GENHD_FL_NO_PART_SCAN			0x0200
+#define GENHD_FL_NO_PART			0x0200
 #define GENHD_FL_HIDDEN				0x0400
 
 enum {
@@ -180,8 +180,7 @@ static inline int disk_max_parts(struct gendisk *disk)
 
 static inline bool disk_part_scan_enabled(struct gendisk *disk)
 {
-	return disk_max_parts(disk) > 1 &&
-		!(disk->flags & GENHD_FL_NO_PART_SCAN);
+	return disk_max_parts(disk) > 1 && !(disk->flags & GENHD_FL_NO_PART);
 }
 
 static inline dev_t disk_devt(struct gendisk *disk)
-- 
2.30.2

[PATCH 07/14] block: remove the GENHD_FL_HIDDEN check in blkdev_get_no_open

[Christoph Hellwig]

Hidden gendisks never hash the block device inode, so this can't happen.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bdev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index cf29c6508bff2..ae063041f2910 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -753,8 +753,7 @@ struct block_device *blkdev_get_no_open(dev_t dev)
 
 	if (!bdev)
 		return NULL;
-	if ((bdev->bd_disk->flags & GENHD_FL_HIDDEN) ||
-	    !try_module_get(bdev->bd_disk->fops->owner)) {
+	if (!try_module_get(bdev->bd_disk->fops->owner)) {
 		put_device(&bdev->bd_device);
 		return NULL;
 	}
-- 
2.30.2

[PATCH 08/14] null_blk: don't suppress partitioning information

[Christoph Hellwig]

This manually reverts commit 27290b469051 ("null_blk: suppress invalid
partition info").  The message in that commit log can't appearch as
the flag is never checked during probing, and there is no good reason
to treat null_blk special in /proc/partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/null_blk/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 323af5c9c8026..eb17def1f265e 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1850,7 +1850,7 @@ static int null_gendisk_register(struct nullb *nullb)
 
 	set_capacity(disk, size);
 
-	disk->flags |= GENHD_FL_EXT_DEVT | GENHD_FL_SUPPRESS_PARTITION_INFO;
+	disk->flags |= GENHD_FL_EXT_DEVT;
 	disk->major		= null_major;
 	disk->first_minor	= nullb->index;
 	disk->minors		= 1;
-- 
2.30.2

[PATCH 09/14] mmc: don't set GENHD_FL_SUPPRESS_PARTITION_INFO

[Christoph Hellwig]

This manually reverts 07b652cdbec3 ("mmc: card: Don't show eMMC RPMB and
BOOT areas in /proc/partitions").  Based on the commit description that
change was purely cosmetic.  mmc is the last driver that sets this
flag and thus prevents it from being removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/mmc/core/block.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index a71b3512c877a..2dd93d49d822c 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2397,8 +2397,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	set_disk_ro(md->disk, md->read_only || default_ro);
 	md->disk->flags = GENHD_FL_EXT_DEVT;
 	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
-		md->disk->flags |= GENHD_FL_NO_PART |
-				   GENHD_FL_SUPPRESS_PARTITION_INFO;
+		md->disk->flags |= GENHD_FL_NO_PART;
 
 	/*
 	 * As discussed on lkml, GENHD_FL_REMOVABLE should:
-- 
2.30.2

[PATCH 10/14] block: remove GENHD_FL_SUPPRESS_PARTITION_INFO

[Christoph Hellwig]

This flag is not set directly anywhere and only inherited from
GENHD_FL_HIDDEN.  Just check for GENHD_FL_HIDDEN instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c         | 11 +++--------
 include/linux/genhd.h |  9 +--------
 2 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index b37925ed1d7e9..09abd41249fd4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -496,10 +496,8 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 
 	if (disk->flags & GENHD_FL_HIDDEN) {
 		/*
-		 * Don't let hidden disks show up in /proc/partitions,
-		 * and don't bother scanning for partitions either.
+		 * Don't bother scanning for partitions.
 		 */
-		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 		disk->flags |= GENHD_FL_NO_PART;
 	} else {
 		ret = bdi_register(disk->bdi, "%u:%u",
@@ -725,8 +723,7 @@ void __init printk_all_partitions(void)
 		 * Don't show empty devices or things that have been
 		 * suppressed
 		 */
-		if (get_capacity(disk) == 0 ||
-		    (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
+		if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_HIDDEN))
 			continue;
 
 		/*
@@ -819,9 +816,7 @@ static int show_partition(struct seq_file *seqf, void *v)
 	struct block_device *part;
 	unsigned long idx;
 
-	if (!get_capacity(sgp))
-		return 0;
-	if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
+	if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))
 		return 0;
 
 	rcu_read_lock();
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 0b9be3df94898..64a2f33ae9ea4 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -46,11 +46,6 @@ struct partition_meta_info {
  * Must not be set for devices which are removed entirely when the
  * media is removed.
  *
- * ``GENHD_FL_SUPPRESS_PARTITION_INFO`` (0x0020): don't include
- * partition information in ``/proc/partitions`` or in the output of
- * printk_all_partitions().
- * Used for the null block device and some MMC devices.
- *
  * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
  * dynamic ``dev_t``, i.e. it wants extended device numbers
  * (``BLOCK_EXT_MAJOR``).
@@ -63,14 +58,12 @@ struct partition_meta_info {
  * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
  * doesn't produce events, doesn't appear in sysfs, and doesn't have
  * an associated ``bdev``.
- * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
- * ``GENHD_FL_NO_PART``.
+ * Implies ``GENHD_FL_NO_PART``.
  * Used for multipath devices.
  */
 #define GENHD_FL_REMOVABLE			0x0001
 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
-#define GENHD_FL_SUPPRESS_PARTITION_INFO	0x0020
 #define GENHD_FL_EXT_DEVT			0x0040
 #define GENHD_FL_NO_PART			0x0200
 #define GENHD_FL_HIDDEN				0x0400
-- 
2.30.2

[PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Christoph Hellwig]

All modern drivers can support extra partitions using the extended
dev_t.  In fact except for the ioctl method drivers never even see
partitions in normal operation.

So remove the GENHD_FL_EXT_DEVT and allow extra partitions for all
block devices that do support partitions, and require those that
do not support partitions to explicit disallow them using
GENHD_FL_NO_PART.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c                  |  6 +++---
 block/partitions/core.c        |  9 ++++-----
 drivers/block/amiflop.c        |  1 +
 drivers/block/ataflop.c        |  1 +
 drivers/block/brd.c            |  1 -
 drivers/block/drbd/drbd_main.c |  1 +
 drivers/block/floppy.c         |  1 +
 drivers/block/loop.c           |  1 -
 drivers/block/null_blk/main.c  |  1 -
 drivers/block/paride/pcd.c     |  1 +
 drivers/block/paride/pf.c      |  1 +
 drivers/block/pktcdvd.c        |  2 +-
 drivers/block/ps3vram.c        |  1 +
 drivers/block/rbd.c            |  6 ++----
 drivers/block/swim.c           |  1 +
 drivers/block/swim3.c          |  2 +-
 drivers/block/virtio_blk.c     |  1 -
 drivers/block/z2ram.c          |  1 +
 drivers/block/zram/zram_drv.c  |  1 +
 drivers/cdrom/gdrom.c          |  1 +
 drivers/md/dm.c                |  1 +
 drivers/md/md.c                |  5 -----
 drivers/mmc/core/block.c       |  1 -
 drivers/mtd/ubi/block.c        |  1 +
 drivers/scsi/sd.c              |  1 -
 drivers/scsi/sr.c              |  1 +
 include/linux/genhd.h          | 28 +++++-----------------------
 27 files changed, 30 insertions(+), 48 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 09abd41249fd4..e9346fae48ad4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -376,7 +376,7 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 {
 	struct block_device *bdev;
 
-	if (!disk_part_scan_enabled(disk))
+	if (disk->flags & GENHD_FL_NO_PART)
 		return -EINVAL;
 	if (disk->open_partitions)
 		return -EBUSY;
@@ -438,7 +438,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 			return ret;
 		disk->major = BLOCK_EXT_MAJOR;
 		disk->first_minor = ret;
-		disk->flags |= GENHD_FL_EXT_DEVT;
 	}
 
 	ret = disk_alloc_events(disk);
@@ -872,7 +871,8 @@ static ssize_t disk_ext_range_show(struct device *dev,
 {
 	struct gendisk *disk = dev_to_disk(dev);
 
-	return sprintf(buf, "%d\n", disk_max_parts(disk));
+	return sprintf(buf, "%d\n",
+		(disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);
 }
 
 static ssize_t disk_removable_show(struct device *dev,
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 520292fee9339..c2a1635922b1c 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -98,13 +98,12 @@ static void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
 {
 	struct parsed_partitions *state;
-	int nr;
+	int nr = DISK_MAX_PARTS;
 
 	state = kzalloc(sizeof(*state), GFP_KERNEL);
 	if (!state)
 		return NULL;
 
-	nr = disk_max_parts(hd);
 	state->parts = vzalloc(array_size(nr, sizeof(state->parts[0])));
 	if (!state->parts) {
 		kfree(state);
@@ -326,7 +325,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 
 	lockdep_assert_held(&disk->open_mutex);
 
-	if (partno >= disk_max_parts(disk))
+	if (partno >= DISK_MAX_PARTS)
 		return ERR_PTR(-EINVAL);
 
 	/*
@@ -604,7 +603,7 @@ static int blk_add_partitions(struct gendisk *disk)
 	struct parsed_partitions *state;
 	int ret = -EAGAIN, p;
 
-	if (!disk_part_scan_enabled(disk))
+	if (disk->flags & GENHD_FL_NO_PART)
 		return 0;
 
 	state = check_partition(disk);
@@ -687,7 +686,7 @@ int bdev_disk_changed(struct gendisk *disk, bool invalidate)
 	 * userspace for this particular setup.
 	 */
 	if (invalidate) {
-		if (disk_part_scan_enabled(disk) ||
+		if (!(disk->flags & GENHD_FL_NO_PART) ||
 		    !(disk->flags & GENHD_FL_REMOVABLE))
 			set_capacity(disk, 0);
 	}
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index bf5c124c5452a..1eec5113d0b5b 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -1790,6 +1790,7 @@ static int fd_alloc_disk(int drive, int system)
 	disk->first_minor = drive + system;
 	disk->minors = 1;
 	disk->fops = &floppy_fops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	if (system)
 		sprintf(disk->disk_name, "fd%d_msdos", drive);
diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index bf769e6e32fef..f3ff9babdb5cd 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -2000,6 +2000,7 @@ static int ataflop_alloc_disk(unsigned int drive, unsigned int type)
 	disk->minors = 1;
 	sprintf(disk->disk_name, "fd%d", drive);
 	disk->fops = &floppy_fops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	disk->private_data = &unit[drive];
 	set_capacity(disk, MAX_DISK_SIZE * 2);
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index a896ee175d863..8fe2e4289dae3 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -405,7 +405,6 @@ static int brd_alloc(int i)
 	disk->minors		= max_part;
 	disk->fops		= &brd_fops;
 	disk->private_data	= brd;
-	disk->flags		= GENHD_FL_EXT_DEVT;
 	strlcpy(disk->disk_name, buf, DISK_NAME_LEN);
 	set_capacity(disk, rd_size * 2);
 	
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 53ba2dddba6e6..07b3c6093e7db 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2734,6 +2734,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	disk->first_minor = minor;
 	disk->minors = 1;
 	disk->fops = &drbd_ops;
+	disk->flags |= GENHD_FL_NO_PART;
 	sprintf(disk->disk_name, "drbd%d", minor);
 	disk->private_data = device;
 
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index c4267da716fe6..7f0a60c4079fd 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4503,6 +4503,7 @@ static int floppy_alloc_disk(unsigned int drive, unsigned int type)
 	disk->first_minor = TOMINOR(drive) | (type << 2);
 	disk->minors = 1;
 	disk->fops = &floppy_fops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	if (type)
 		sprintf(disk->disk_name, "fd%d_type%d", drive, type);
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 7219d98c6fb8a..0954ea8cf9e3b 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2033,7 +2033,6 @@ static int loop_add(int i)
 	 */
 	if (!part_shift)
 		disk->flags |= GENHD_FL_NO_PART;
-	disk->flags |= GENHD_FL_EXT_DEVT;
 	atomic_set(&lo->lo_refcnt, 0);
 	mutex_init(&lo->lo_mutex);
 	lo->lo_number		= i;
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index eb17def1f265e..54f7d490f8ebb 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1850,7 +1850,6 @@ static int null_gendisk_register(struct nullb *nullb)
 
 	set_capacity(disk, size);
 
-	disk->flags |= GENHD_FL_EXT_DEVT;
 	disk->major		= null_major;
 	disk->first_minor	= nullb->index;
 	disk->minors		= 1;
diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index 430ee8004a514..255fd3d4b8a84 100644
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -928,6 +928,7 @@ static int pcd_init_unit(struct pcd_unit *cd, bool autoprobe, int port,
 	disk->minors = 1;
 	strcpy(disk->disk_name, cd->name);	/* umm... */
 	disk->fops = &pcd_bdops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	disk->event_flags = DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
 
diff --git a/drivers/block/paride/pf.c b/drivers/block/paride/pf.c
index bf8d0ef41a0a2..b84a6448a4f75 100644
--- a/drivers/block/paride/pf.c
+++ b/drivers/block/paride/pf.c
@@ -942,6 +942,7 @@ static int __init pf_init_unit(struct pf_unit *pf, bool autoprobe, int port,
 	disk->minors = 1;
 	strcpy(disk->disk_name, pf->name);
 	disk->fops = &pf_fops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	disk->private_data = pf;
 
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index b53f648302c15..3af0499857ecf 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2719,7 +2719,7 @@ static int pkt_setup_dev(dev_t dev, dev_t* pkt_dev)
 	disk->first_minor = idx;
 	disk->minors = 1;
 	disk->fops = &pktcdvd_ops;
-	disk->flags = GENHD_FL_REMOVABLE;
+	disk->flags = GENHD_FL_REMOVABLE | GENHD_FL_NO_PART;
 	strcpy(disk->disk_name, pd->name);
 	disk->private_data = pd;
 
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index c1876646a4cb9..4f90819e245e9 100644
--- a/drivers/block/ps3vram.c
+++ b/drivers/block/ps3vram.c
@@ -742,6 +742,7 @@ static int ps3vram_probe(struct ps3_system_bus_device *dev)
 	priv->gendisk = gendisk;
 	gendisk->major = ps3vram_major;
 	gendisk->minors = 1;
+	gendisk->flags |= GENHD_FL_NO_PART;
 	gendisk->fops = &ps3vram_fops;
 	gendisk->private_data = dev;
 	strlcpy(gendisk->disk_name, DEVICE_NAME, sizeof(gendisk->disk_name));
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 953fa134cd3db..8f140da1efe30 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4924,12 +4924,10 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 		 rbd_dev->dev_id);
 	disk->major = rbd_dev->major;
 	disk->first_minor = rbd_dev->minor;
-	if (single_major) {
+	if (single_major)
 		disk->minors = (1 << RBD_SINGLE_MAJOR_PART_SHIFT);
-		disk->flags |= GENHD_FL_EXT_DEVT;
-	} else {
+	else
 		disk->minors = RBD_MINORS_PER_MAJOR;
-	}
 	disk->fops = &rbd_bd_ops;
 	disk->private_data = rbd_dev;
 
diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index 821594cd13151..fef65a18d56fa 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -840,6 +840,7 @@ static int swim_floppy_init(struct swim_priv *swd)
 		swd->unit[drive].disk->minors = 1;
 		sprintf(swd->unit[drive].disk->disk_name, "fd%d", drive);
 		swd->unit[drive].disk->fops = &floppy_fops;
+		swd->unit[drive].disk->flags |= GENHD_FL_NO_PART;
 		swd->unit[drive].disk->events = DISK_EVENT_MEDIA_CHANGE;
 		swd->unit[drive].disk->private_data = &swd->unit[drive];
 		set_capacity(swd->unit[drive].disk, 2880);
diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index 4b91c9aa58926..6c39f2c9f806d 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -1227,7 +1227,7 @@ static int swim3_attach(struct macio_dev *mdev,
 	disk->fops = &floppy_fops;
 	disk->private_data = fs;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
-	disk->flags |= GENHD_FL_REMOVABLE;
+	disk->flags |= GENHD_FL_REMOVABLE | GENHD_FL_NO_PART;
 	sprintf(disk->disk_name, "fd%d", floppy_count);
 	set_capacity(disk, 2880);
 	rc = add_disk(disk);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 97bf051a50ced..5bb11a8b02652 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -843,7 +843,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	vblk->disk->minors = 1 << PART_BITS;
 	vblk->disk->private_data = vblk;
 	vblk->disk->fops = &virtblk_fops;
-	vblk->disk->flags |= GENHD_FL_EXT_DEVT;
 	vblk->index = index;
 
 	/* configure queue flush support */
diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index ccc52c935fafc..7a6ed83481b8d 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -327,6 +327,7 @@ static int z2ram_register_disk(int minor)
 	disk->major = Z2RAM_MAJOR;
 	disk->first_minor = minor;
 	disk->minors = 1;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->fops = &z2_fops;
 	if (minor)
 		sprintf(disk->disk_name, "z2ram%d", minor);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 08d7953ec5f10..b4a6a832afe33 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1945,6 +1945,7 @@ static int zram_add(void)
 	zram->disk->major = zram_major;
 	zram->disk->first_minor = device_id;
 	zram->disk->minors = 1;
+	zram->disk->flags |= GENHD_FL_NO_PART;
 	zram->disk->fops = &zram_devops;
 	zram->disk->private_data = zram;
 	snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index d50cc1fd34d5f..faead41709bcd 100644
--- a/drivers/cdrom/gdrom.c
+++ b/drivers/cdrom/gdrom.c
@@ -719,6 +719,7 @@ static void probe_gdrom_setupdisk(void)
 	gd.disk->major = gdrom_major;
 	gd.disk->first_minor = 1;
 	gd.disk->minors = 1;
+	gd.disk->flags |= GENHD_FL_NO_PART;
 	strcpy(gd.disk->disk_name, GDROM_DEV_NAME);
 }
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 662742a310cbb..280918cdcabd3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1778,6 +1778,7 @@ static struct mapped_device *alloc_dev(int minor)
 	md->disk->major = _major;
 	md->disk->first_minor = minor;
 	md->disk->minors = 1;
+	md->disk->flags |= GENHD_FL_NO_PART;
 	md->disk->fops = &dm_blk_dops;
 	md->disk->queue = md->queue;
 	md->disk->private_data = md;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 5111ed966947e..7fbf6f0ac01be 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5707,11 +5707,6 @@ static int md_alloc(dev_t dev, char *name)
 	mddev->queue = disk->queue;
 	blk_set_stacking_limits(&mddev->queue->limits);
 	blk_queue_write_cache(mddev->queue, true, true);
-	/* Allow extended partitions.  This makes the
-	 * 'mdp' device redundant, but we can't really
-	 * remove it now.
-	 */
-	disk->flags |= GENHD_FL_EXT_DEVT;
 	disk->events |= DISK_EVENT_MEDIA_CHANGE;
 	mddev->gendisk = disk;
 	error = add_disk(disk);
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 2dd93d49d822c..5e0960560eab7 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2395,7 +2395,6 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 	md->disk->private_data = md;
 	md->parent = parent;
 	set_disk_ro(md->disk, md->read_only || default_ro);
-	md->disk->flags = GENHD_FL_EXT_DEVT;
 	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
 		md->disk->flags |= GENHD_FL_NO_PART;
 
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 302426ab30f8d..a78fdf3b30f7e 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -430,6 +430,7 @@ int ubiblock_create(struct ubi_volume_info *vi)
 		ret = -ENODEV;
 		goto out_cleanup_disk;
 	}
+	gd->flags |= GENHD_FL_NO_PART;
 	gd->private_data = dev;
 	sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
 	set_capacity(gd, disk_capacity);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 65875a598d629..bba1f5dafd387 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3566,7 +3566,6 @@ static int sd_probe(struct device *dev)
 
 	sd_revalidate_disk(gd);
 
-	gd->flags = GENHD_FL_EXT_DEVT;
 	if (sdp->removable) {
 		gd->flags |= GENHD_FL_REMOVABLE;
 		gd->events |= DISK_EVENT_MEDIA_CHANGE;
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 6646797a7756e..cf093387e42a1 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -684,6 +684,7 @@ static int sr_probe(struct device *dev)
 	disk->minors = 1;
 	sprintf(disk->disk_name, "sr%d", minor);
 	disk->fops = &sr_bdops;
+	disk->flags |= GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
 	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT |
 				DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 64a2f33ae9ea4..b8ced80178d64 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -46,11 +46,6 @@ struct partition_meta_info {
  * Must not be set for devices which are removed entirely when the
  * media is removed.
  *
- * ``GENHD_FL_EXT_DEVT`` (0x0040): the driver supports extended
- * dynamic ``dev_t``, i.e. it wants extended device numbers
- * (``BLOCK_EXT_MAJOR``).
- * This affects the maximum number of partitions.
- *
  * ``GENHD_FL_NO_PART`` (0x0200): partition support is disabled.
  * The kernel will not scan for partitions from add_disk, and users
  * can't add partitions manually.
@@ -64,7 +59,6 @@ struct partition_meta_info {
 #define GENHD_FL_REMOVABLE			0x0001
 /* 2 is unused (used to be GENHD_FL_DRIVERFS) */
 /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
-#define GENHD_FL_EXT_DEVT			0x0040
 #define GENHD_FL_NO_PART			0x0200
 #define GENHD_FL_HIDDEN				0x0400
 
@@ -94,13 +88,13 @@ struct blk_integrity {
 };
 
 struct gendisk {
-	/* major, first_minor and minors are input parameters only,
-	 * don't use directly.  Use disk_devt() and disk_max_parts().
+	/*
+	 * major/first_minor/minors should not be set by any new driver, the
+	 * block core will take care of allocating them automatically.
 	 */
-	int major;			/* major number of driver */
+	int major;
 	int first_minor;
-	int minors;                     /* maximum number of minors, =1 for
-                                         * disks that can't be partitioned. */
+	int minors;
 
 	char disk_name[DISK_NAME_LEN];	/* name of major driver */
 
@@ -164,18 +158,6 @@ static inline bool disk_live(struct gendisk *disk)
 #define disk_to_cdi(disk)	NULL
 #endif
 
-static inline int disk_max_parts(struct gendisk *disk)
-{
-	if (disk->flags & GENHD_FL_EXT_DEVT)
-		return DISK_MAX_PARTS;
-	return disk->minors;
-}
-
-static inline bool disk_part_scan_enabled(struct gendisk *disk)
-{
-	return disk_max_parts(disk) > 1 && !(disk->flags & GENHD_FL_NO_PART);
-}
-
 static inline dev_t disk_devt(struct gendisk *disk)
 {
 	return MKDEV(disk->major, disk->first_minor);
-- 
2.30.2

[PATCH 12/14] block: don't set GENHD_FL_NO_PART for hidden gendisks

[Christoph Hellwig]

Hidden gendisks can't be opened using blkdev_get_*, so we can't really
reach any of the partition scanning paths or partitioning ioctls except
for the initial partition scan from add_disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e9346fae48ad4..b1c194813e22f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -376,7 +376,7 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 {
 	struct block_device *bdev;
 
-	if (disk->flags & GENHD_FL_NO_PART)
+	if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
 		return -EINVAL;
 	if (disk->open_partitions)
 		return -EBUSY;
@@ -493,12 +493,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 	if (ret)
 		goto out_put_slave_dir;
 
-	if (disk->flags & GENHD_FL_HIDDEN) {
-		/*
-		 * Don't bother scanning for partitions.
-		 */
-		disk->flags |= GENHD_FL_NO_PART;
-	} else {
+	if (!(disk->flags & GENHD_FL_HIDDEN)) {
 		ret = bdi_register(disk->bdi, "%u:%u",
 				   disk->major, disk->first_minor);
 		if (ret)
-- 
2.30.2

[PATCH 13/14] block: cleanup the GENHD_FL_* definitions

[Christoph Hellwig]

Switch to an enum and tidy up the documentation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/genhd.h | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index b8ced80178d64..6906a45bc761a 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -39,28 +39,24 @@ struct partition_meta_info {
 /**
  * DOC: genhd capability flags
  *
- * ``GENHD_FL_REMOVABLE`` (0x0001): indicates that the block device
- * gives access to removable media.
- * When set, the device remains present even when media is not
- * inserted.
- * Must not be set for devices which are removed entirely when the
+ * ``GENHD_FL_REMOVABLE``: indicates that the block device gives access to
+ * removable media.  When set, the device remains present even when media is not
+ * inserted.  Shall not be set for devices which are removed entirely when the
  * media is removed.
  *
- * ``GENHD_FL_NO_PART`` (0x0200): partition support is disabled.
- * The kernel will not scan for partitions from add_disk, and users
- * can't add partitions manually.
+ * ``GENHD_FL_HIDDEN``: the block device is hidden; it doesn't produce events,
+ * doesn't appear in sysfs, and can't be opened from userspace or using
+ * blkdev_get*. Used for the underlying components of multipath devices.
+ *
+ * ``GENHD_FL_NO_PART``: partition support is disabled.  The kernel will not
+ * scan for partitions from add_disk, and users can't add partitions manually.
  *
- * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
- * doesn't produce events, doesn't appear in sysfs, and doesn't have
- * an associated ``bdev``.
- * Implies ``GENHD_FL_NO_PART``.
- * Used for multipath devices.
  */
-#define GENHD_FL_REMOVABLE			0x0001
-/* 2 is unused (used to be GENHD_FL_DRIVERFS) */
-/* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
-#define GENHD_FL_NO_PART			0x0200
-#define GENHD_FL_HIDDEN				0x0400
+enum {
+	GENHD_FL_REMOVABLE			= 1 << 0,
+	GENHD_FL_HIDDEN				= 1 << 1,
+	GENHD_FL_NO_PART			= 1 << 2,
+};
 
 enum {
 	DISK_EVENT_MEDIA_CHANGE			= 1 << 0, /* media changed */
-- 
2.30.2

[PATCH 14/14] sr: set GENHD_FL_REMOVABLE earlier

[Christoph Hellwig]

Set up GENHD_FL_REMOVABLE together with the rest of the gendisk fields.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sr.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index cf093387e42a1..411e2b01966e8 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -684,7 +684,7 @@ static int sr_probe(struct device *dev)
 	disk->minors = 1;
 	sprintf(disk->disk_name, "sr%d", minor);
 	disk->fops = &sr_bdops;
-	disk->flags |= GENHD_FL_NO_PART;
+	disk->flags |= GENHD_FL_REMOVABLE | GENHD_FL_NO_PART;
 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
 	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT |
 				DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE;
@@ -726,7 +726,6 @@ static int sr_probe(struct device *dev)
 	blk_pm_runtime_init(sdev->request_queue, dev);
 
 	dev_set_drvdata(dev, cd);
-	disk->flags |= GENHD_FL_REMOVABLE;
 	sr_revalidate_disk(cd);
 
 	error = device_add_disk(&sdev->sdev_gendev, disk, NULL);
-- 
2.30.2

Re: [PATCH 06/14] block: rename GENHD_FL_NO_PART_SCAN to GENHD_FL_NO_PART

[Ulf Hansson]

On Mon, 22 Nov 2021 at 14:06, Christoph Hellwig <hch@lst.de> wrote:
>
> The GENHD_FL_NO_PART_SCAN controls more than just partitions canning,
> so rename it to GENHD_FL_NO_PART.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe


> ---
>  block/genhd.c            |  2 +-
>  drivers/block/loop.c     |  8 ++++----
>  drivers/block/n64cart.c  |  2 +-
>  drivers/mmc/core/block.c |  4 ++--
>  include/linux/genhd.h    | 13 ++++++-------
>  5 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 0cf3d30429e14..b37925ed1d7e9 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -500,7 +500,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
>                  * and don't bother scanning for partitions either.
>                  */
>                 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
> -               disk->flags |= GENHD_FL_NO_PART_SCAN;
> +               disk->flags |= GENHD_FL_NO_PART;
>         } else {
>                 ret = bdi_register(disk->bdi, "%u:%u",
>                                    disk->major, disk->first_minor);
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index a154cab6cd989..7219d98c6fb8a 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1061,7 +1061,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>                 lo->lo_flags |= LO_FLAGS_PARTSCAN;
>         partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
>         if (partscan)
> -               lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
> +               lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
>
>         loop_global_unlock(lo, is_loop);
>         if (partscan)
> @@ -1191,7 +1191,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
>         mutex_lock(&lo->lo_mutex);
>         lo->lo_flags = 0;
>         if (!part_shift)
> -               lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
> +               lo->lo_disk->flags |= GENHD_FL_NO_PART;
>         lo->lo_state = Lo_unbound;
>         mutex_unlock(&lo->lo_mutex);
>
> @@ -1301,7 +1301,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
>
>         if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
>              !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
> -               lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
> +               lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
>                 partscan = true;
>         }
>  out_unlock:
> @@ -2032,7 +2032,7 @@ static int loop_add(int i)
>          * userspace tools. Parameters like this in general should be avoided.
>          */
>         if (!part_shift)
> -               disk->flags |= GENHD_FL_NO_PART_SCAN;
> +               disk->flags |= GENHD_FL_NO_PART;
>         disk->flags |= GENHD_FL_EXT_DEVT;
>         atomic_set(&lo->lo_refcnt, 0);
>         mutex_init(&lo->lo_mutex);
> diff --git a/drivers/block/n64cart.c b/drivers/block/n64cart.c
> index 78282f01f5813..4db9a8c244af5 100644
> --- a/drivers/block/n64cart.c
> +++ b/drivers/block/n64cart.c
> @@ -136,7 +136,7 @@ static int __init n64cart_probe(struct platform_device *pdev)
>                 goto out;
>
>         disk->first_minor = 0;
> -       disk->flags = GENHD_FL_NO_PART_SCAN;
> +       disk->flags = GENHD_FL_NO_PART;
>         disk->fops = &n64cart_fops;
>         disk->private_data = &pdev->dev;
>         strcpy(disk->disk_name, "n64cart");
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index 90e1bcd03b46c..a71b3512c877a 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -2397,8 +2397,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
>         set_disk_ro(md->disk, md->read_only || default_ro);
>         md->disk->flags = GENHD_FL_EXT_DEVT;
>         if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
> -               md->disk->flags |= GENHD_FL_NO_PART_SCAN
> -                                  | GENHD_FL_SUPPRESS_PARTITION_INFO;
> +               md->disk->flags |= GENHD_FL_NO_PART |
> +                                  GENHD_FL_SUPPRESS_PARTITION_INFO;
>
>         /*
>          * As discussed on lkml, GENHD_FL_REMOVABLE should:
> diff --git a/include/linux/genhd.h b/include/linux/genhd.h
> index 74518c576fbb9..0b9be3df94898 100644
> --- a/include/linux/genhd.h
> +++ b/include/linux/genhd.h
> @@ -56,15 +56,15 @@ struct partition_meta_info {
>   * (``BLOCK_EXT_MAJOR``).
>   * This affects the maximum number of partitions.
>   *
> - * ``GENHD_FL_NO_PART_SCAN`` (0x0200): partition scanning is disabled.
> - * Used for loop devices in their default settings and some MMC
> - * devices.
> + * ``GENHD_FL_NO_PART`` (0x0200): partition support is disabled.
> + * The kernel will not scan for partitions from add_disk, and users
> + * can't add partitions manually.
>   *
>   * ``GENHD_FL_HIDDEN`` (0x0400): the block device is hidden; it
>   * doesn't produce events, doesn't appear in sysfs, and doesn't have
>   * an associated ``bdev``.
>   * Implies ``GENHD_FL_SUPPRESS_PARTITION_INFO`` and
> - * ``GENHD_FL_NO_PART_SCAN``.
> + * ``GENHD_FL_NO_PART``.
>   * Used for multipath devices.
>   */
>  #define GENHD_FL_REMOVABLE                     0x0001
> @@ -72,7 +72,7 @@ struct partition_meta_info {
>  /* 4 is unused (used to be GENHD_FL_MEDIA_CHANGE_NOTIFY) */
>  #define GENHD_FL_SUPPRESS_PARTITION_INFO       0x0020
>  #define GENHD_FL_EXT_DEVT                      0x0040
> -#define GENHD_FL_NO_PART_SCAN                  0x0200
> +#define GENHD_FL_NO_PART                       0x0200
>  #define GENHD_FL_HIDDEN                                0x0400
>
>  enum {
> @@ -180,8 +180,7 @@ static inline int disk_max_parts(struct gendisk *disk)
>
>  static inline bool disk_part_scan_enabled(struct gendisk *disk)
>  {
> -       return disk_max_parts(disk) > 1 &&
> -               !(disk->flags & GENHD_FL_NO_PART_SCAN);
> +       return disk_max_parts(disk) > 1 && !(disk->flags & GENHD_FL_NO_PART);
>  }
>
>  static inline dev_t disk_devt(struct gendisk *disk)
> --
> 2.30.2
>

Re: [PATCH 09/14] mmc: don't set GENHD_FL_SUPPRESS_PARTITION_INFO

[Ulf Hansson]

On Mon, 22 Nov 2021 at 14:06, Christoph Hellwig <hch@lst.de> wrote:
>
> This manually reverts 07b652cdbec3 ("mmc: card: Don't show eMMC RPMB and
> BOOT areas in /proc/partitions").  Based on the commit description that
> change was purely cosmetic.  mmc is the last driver that sets this
> flag and thus prevents it from being removed.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe


> ---
>  drivers/mmc/core/block.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index a71b3512c877a..2dd93d49d822c 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -2397,8 +2397,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
>         set_disk_ro(md->disk, md->read_only || default_ro);
>         md->disk->flags = GENHD_FL_EXT_DEVT;
>         if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
> -               md->disk->flags |= GENHD_FL_NO_PART |
> -                                  GENHD_FL_SUPPRESS_PARTITION_INFO;
> +               md->disk->flags |= GENHD_FL_NO_PART;
>
>         /*
>          * As discussed on lkml, GENHD_FL_REMOVABLE should:
> --
> 2.30.2
>

Re: cleanup and simplify the gendisk flags

[Jens Axboe]

On Mon, 22 Nov 2021 14:06:11 +0100, Christoph Hellwig wrote:
> Ho Jens,
> 
> the gendisk flags have been a complete mess for a while.  This series
> tries to untangle them as much as easily possible.
> 
> Diffstat:
>  block/bdev.c                       |    5 --
>  block/blk.h                        |    1
>  block/genhd.c                      |   41 +++++++----------
>  block/ioctl.c                      |   31 ++-----------
>  block/partitions/core.c            |   24 ++++------
>  drivers/block/amiflop.c            |    1
>  drivers/block/ataflop.c            |    1
>  drivers/block/brd.c                |    1
>  drivers/block/drbd/drbd_main.c     |    1
>  drivers/block/floppy.c             |    1
>  drivers/block/loop.c               |    9 +--
>  drivers/block/n64cart.c            |    2
>  drivers/block/null_blk/main.c      |    1
>  drivers/block/paride/pcd.c         |    3 -
>  drivers/block/paride/pf.c          |    1
>  drivers/block/pktcdvd.c            |    2
>  drivers/block/ps3vram.c            |    1
>  drivers/block/rbd.c                |    6 --
>  drivers/block/sunvdc.c             |   17 +++----
>  drivers/block/swim.c               |    1
>  drivers/block/swim3.c              |    2
>  drivers/block/virtio_blk.c         |    1
>  drivers/block/xen-blkback/xenbus.c |    2
>  drivers/block/xen-blkfront.c       |   26 ++++-------
>  drivers/block/z2ram.c              |    1
>  drivers/block/zram/zram_drv.c      |    1
>  drivers/cdrom/gdrom.c              |    1
>  drivers/md/dm.c                    |    1
>  drivers/md/md.c                    |    5 --
>  drivers/mmc/core/block.c           |    4 -
>  drivers/mtd/ubi/block.c            |    1
>  drivers/scsi/sd.c                  |    1
>  drivers/scsi/sr.c                  |    6 +-
>  include/linux/genhd.h              |   85 +++++++++----------------------------
>  34 files changed, 104 insertions(+), 183 deletions(-)
> 
> [...]

Applied, thanks!

[01/14] block: move GENHD_FL_NATIVE_CAPACITY to disk->state
        (no commit info)
[02/14] block: move GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE to disk->event_flags
        (no commit info)
[03/14] block: remove GENHD_FL_CD
        (no commit info)
[04/14] block: remove a dead check in show_partition
        (no commit info)
[05/14] block: merge disk_scan_partitions and blkdev_reread_part
        (no commit info)
[06/14] block: rename GENHD_FL_NO_PART_SCAN to GENHD_FL_NO_PART
        (no commit info)
[07/14] block: remove the GENHD_FL_HIDDEN check in blkdev_get_no_open
        (no commit info)
[08/14] null_blk: don't suppress partitioning information
        (no commit info)
[09/14] mmc: don't set GENHD_FL_SUPPRESS_PARTITION_INFO
        (no commit info)
[10/14] block: remove GENHD_FL_SUPPRESS_PARTITION_INFO
        (no commit info)
[11/14] block: remove GENHD_FL_EXT_DEVT
        (no commit info)
[12/14] block: don't set GENHD_FL_NO_PART for hidden gendisks
        (no commit info)
[13/14] block: cleanup the GENHD_FL_* definitions
        (no commit info)
[14/14] sr: set GENHD_FL_REMOVABLE earlier
        (no commit info)

Best regards,
-- 
Jens Axboe

Re: [PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Ming Lei]

Hi Christoph,

On Mon, Nov 22, 2021 at 02:06:22PM +0100, Christoph Hellwig wrote:
> All modern drivers can support extra partitions using the extended
> dev_t.  In fact except for the ioctl method drivers never even see
> partitions in normal operation.
> 
> So remove the GENHD_FL_EXT_DEVT and allow extra partitions for all
> block devices that do support partitions, and require those that
> do not support partitions to explicit disallow them using
> GENHD_FL_NO_PART.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/genhd.c                  |  6 +++---
>  block/partitions/core.c        |  9 ++++-----
>  drivers/block/amiflop.c        |  1 +
>  drivers/block/ataflop.c        |  1 +
>  drivers/block/brd.c            |  1 -
>  drivers/block/drbd/drbd_main.c |  1 +
>  drivers/block/floppy.c         |  1 +
>  drivers/block/loop.c           |  1 -
>  drivers/block/null_blk/main.c  |  1 -
>  drivers/block/paride/pcd.c     |  1 +
>  drivers/block/paride/pf.c      |  1 +
>  drivers/block/pktcdvd.c        |  2 +-
>  drivers/block/ps3vram.c        |  1 +
>  drivers/block/rbd.c            |  6 ++----
>  drivers/block/swim.c           |  1 +
>  drivers/block/swim3.c          |  2 +-
>  drivers/block/virtio_blk.c     |  1 -
>  drivers/block/z2ram.c          |  1 +
>  drivers/block/zram/zram_drv.c  |  1 +
>  drivers/cdrom/gdrom.c          |  1 +
>  drivers/md/dm.c                |  1 +
>  drivers/md/md.c                |  5 -----
>  drivers/mmc/core/block.c       |  1 -
>  drivers/mtd/ubi/block.c        |  1 +
>  drivers/scsi/sd.c              |  1 -
>  drivers/scsi/sr.c              |  1 +
>  include/linux/genhd.h          | 28 +++++-----------------------
>  27 files changed, 30 insertions(+), 48 deletions(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 09abd41249fd4..e9346fae48ad4 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -376,7 +376,7 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
>  {
>  	struct block_device *bdev;
>  
> -	if (!disk_part_scan_enabled(disk))
> +	if (disk->flags & GENHD_FL_NO_PART)
>  		return -EINVAL;
>  	if (disk->open_partitions)
>  		return -EBUSY;
> @@ -438,7 +438,6 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
>  			return ret;
>  		disk->major = BLOCK_EXT_MAJOR;
>  		disk->first_minor = ret;
> -		disk->flags |= GENHD_FL_EXT_DEVT;
>  	}
>  
>  	ret = disk_alloc_events(disk);
> @@ -872,7 +871,8 @@ static ssize_t disk_ext_range_show(struct device *dev,
>  {
>  	struct gendisk *disk = dev_to_disk(dev);
>  
> -	return sprintf(buf, "%d\n", disk_max_parts(disk));
> +	return sprintf(buf, "%d\n",
> +		(disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);

The above change breaks parted on loop, which reads 'ext_range' to add
partitions.

Follows the test case:

	fallocate -l 4096M loop0.img
	losetup /dev/loop0 loop0.img
	parted -s /dev/loop0 mklabel MSDOS
	parted -s /dev/loop0 mkpart pri 1 1248

Since this patch is merged, /dev/loop0p1 can't be created any more
by above script.



Thanks,
Ming

Re: [PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Christoph Hellwig]

On Wed, May 25, 2022 at 10:35:56PM +0800, Ming Lei wrote:
> > @@ -872,7 +871,8 @@ static ssize_t disk_ext_range_show(struct device *dev,
> >  {
> >  	struct gendisk *disk = dev_to_disk(dev);
> >  
> > -	return sprintf(buf, "%d\n", disk_max_parts(disk));
> > +	return sprintf(buf, "%d\n",
>
>
> The above change breaks parted on loop, which reads 'ext_range' to add
> partitions.

That change alone is not the one breaking it alone, as even if the
file reported something else you still could not create new partitions.

Something like the test below should fix it, but I'll need some more
time to actually test it:

diff --git a/block/genhd.c b/block/genhd.c
index 36532b9318419..27205ae47d593 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -385,6 +385,8 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 
 	if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
 		return -EINVAL;
+	if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
+		return -EINVAL;
 	if (disk->open_partitions)
 		return -EBUSY;
 
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index e2cb51810e89a..5bef97ffbe21e 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1102,7 +1102,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
 	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
 	if (partscan)
-		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
+		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
 
 	loop_global_unlock(lo, is_loop);
 	if (partscan)
@@ -1198,7 +1198,7 @@ static void __loop_clr_fd(struct loop_device *lo, bool release)
 	 */
 	lo->lo_flags = 0;
 	if (!part_shift)
-		lo->lo_disk->flags |= GENHD_FL_NO_PART;
+		set_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
 	mutex_lock(&lo->lo_mutex);
 	lo->lo_state = Lo_unbound;
 	mutex_unlock(&lo->lo_mutex);
@@ -1308,7 +1308,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 
 	if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
 	     !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
-		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
+		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
 		partscan = true;
 	}
 out_unlock:
@@ -2011,7 +2011,7 @@ static int loop_add(int i)
 	 * userspace tools. Parameters like this in general should be avoided.
 	 */
 	if (!part_shift)
-		disk->flags |= GENHD_FL_NO_PART;
+		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
 	mutex_init(&lo->lo_mutex);
 	lo->lo_number		= i;
 	spin_lock_init(&lo->lo_lock);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1b24c1fb3bb1e..bf0c85cfdd8bf 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -147,6 +147,7 @@ struct gendisk {
 #define GD_DEAD				2
 #define GD_NATIVE_CAPACITY		3
 #define GD_ADDED			4
+#define GD_SUPPRESS_PART_SCAN		4
 
 	struct mutex open_mutex;	/* open/close mutex */
 	unsigned open_partitions;	/* number of open partitions */

Re: [PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Christoph Hellwig]

On Wed, May 25, 2022 at 06:51:14PM +0200, Christoph Hellwig wrote:
>  #define GD_ADDED			4
> +#define GD_SUPPRESS_PART_SCAN		4

.. and this should be 5 obviously.

Re: [PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Ming Lei]

On Wed, May 25, 2022 at 06:51:14PM +0200, Christoph Hellwig wrote:
> On Wed, May 25, 2022 at 10:35:56PM +0800, Ming Lei wrote:
> > > @@ -872,7 +871,8 @@ static ssize_t disk_ext_range_show(struct device *dev,
> > >  {
> > >  	struct gendisk *disk = dev_to_disk(dev);
> > >  
> > > -	return sprintf(buf, "%d\n", disk_max_parts(disk));
> > > +	return sprintf(buf, "%d\n",
> >
> >
> > The above change breaks parted on loop, which reads 'ext_range' to add
> > partitions.
> 
> That change alone is not the one breaking it alone, as even if the
> file reported something else you still could not create new partitions.
> 
> Something like the test below should fix it, but I'll need some more
> time to actually test it:
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 36532b9318419..27205ae47d593 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -385,6 +385,8 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
>  
>  	if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
>  		return -EINVAL;
> +	if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
> +		return -EINVAL;
>  	if (disk->open_partitions)
>  		return -EBUSY;
>  
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index e2cb51810e89a..5bef97ffbe21e 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1102,7 +1102,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  		lo->lo_flags |= LO_FLAGS_PARTSCAN;
>  	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
>  	if (partscan)
> -		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
> +		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
>  
>  	loop_global_unlock(lo, is_loop);
>  	if (partscan)
> @@ -1198,7 +1198,7 @@ static void __loop_clr_fd(struct loop_device *lo, bool release)
>  	 */
>  	lo->lo_flags = 0;
>  	if (!part_shift)
> -		lo->lo_disk->flags |= GENHD_FL_NO_PART;
> +		set_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
>  	mutex_lock(&lo->lo_mutex);
>  	lo->lo_state = Lo_unbound;
>  	mutex_unlock(&lo->lo_mutex);
> @@ -1308,7 +1308,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
>  
>  	if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
>  	     !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
> -		lo->lo_disk->flags &= ~GENHD_FL_NO_PART;
> +		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
>  		partscan = true;
>  	}
>  out_unlock:
> @@ -2011,7 +2011,7 @@ static int loop_add(int i)
>  	 * userspace tools. Parameters like this in general should be avoided.
>  	 */
>  	if (!part_shift)
> -		disk->flags |= GENHD_FL_NO_PART;
> +		set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>  	mutex_init(&lo->lo_mutex);
>  	lo->lo_number		= i;
>  	spin_lock_init(&lo->lo_lock);
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 1b24c1fb3bb1e..bf0c85cfdd8bf 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -147,6 +147,7 @@ struct gendisk {
>  #define GD_DEAD				2
>  #define GD_NATIVE_CAPACITY		3
>  #define GD_ADDED			4
> +#define GD_SUPPRESS_PART_SCAN		4
>  
>  	struct mutex open_mutex;	/* open/close mutex */
>  	unsigned open_partitions;	/* number of open partitions */

The patch itself can fix the issue in this test case, since ext_range
recovers to 256.

BTW, SUPPRESS_PART_SCAN looks more like one flag, instead of 'state'.



Thanks,
Ming

Re: [PATCH 11/14] block: remove GENHD_FL_EXT_DEVT

[Christoph Hellwig]

On Thu, May 26, 2022 at 11:06:47AM +0800, Ming Lei wrote:
> BTW, SUPPRESS_PART_SCAN looks more like one flag, instead of 'state'.

It is kinda inbetween, but I favour the state.  ->flags is suppoed to be
set statically at initialization time, and the GENHD_FL_NO_PART usage
by loop is the only thing that violates it.  And once a device declares
support for partitions supresing the scans is basically a policy and thus
a state anyway.