From 8ddcd653257c18a669fcb75ee42c37054908e0d6 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 2 Nov 2017 21:29:53 +0300 Subject: block: introduce GENHD_FL_HIDDEN With this flag a driver can create a gendisk that can be used for I/O submission inside the kernel, but which is not registered as user facing block device. This will be useful for the NVMe multipath implementation. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/genhd.c | 68 +++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 50 insertions(+), 18 deletions(-) (limited to 'block/genhd.c') diff --git a/block/genhd.c b/block/genhd.c index 1174d24e405ee..835e907e6e015 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -585,6 +585,11 @@ static void register_disk(struct device *parent, struct gendisk *disk) */ pm_runtime_set_memalloc_noio(ddev, true); + if (disk->flags & GENHD_FL_HIDDEN) { + dev_set_uevent_suppress(ddev, 0); + return; + } + disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj); disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); @@ -616,6 +621,11 @@ exit: while ((part = disk_part_iter_next(&piter))) kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD); disk_part_iter_exit(&piter); + + err = sysfs_create_link(&ddev->kobj, + &disk->queue->backing_dev_info->dev->kobj, + "bdi"); + WARN_ON(err); } /** @@ -630,7 +640,6 @@ exit: */ void device_add_disk(struct device *parent, struct gendisk *disk) { - struct backing_dev_info *bdi; dev_t devt; int retval; @@ -639,7 +648,8 @@ void device_add_disk(struct device *parent, struct gendisk *disk) * parameters make sense. */ WARN_ON(disk->minors && !(disk->major || disk->first_minor)); - WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT)); + WARN_ON(!disk->minors && + !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN))); disk->flags |= GENHD_FL_UP; @@ -648,18 +658,26 @@ void device_add_disk(struct device *parent, struct gendisk *disk) WARN_ON(1); return; } - disk_to_dev(disk)->devt = devt; disk->major = MAJOR(devt); disk->first_minor = MINOR(devt); disk_alloc_events(disk); - /* Register BDI before referencing it from bdev */ - bdi = disk->queue->backing_dev_info; - bdi_register_owner(bdi, disk_to_dev(disk)); - - blk_register_region(disk_devt(disk), disk->minors, NULL, - exact_match, exact_lock, 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. + */ + disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; + disk->flags |= GENHD_FL_NO_PART_SCAN; + } else { + /* Register BDI before referencing it from bdev */ + disk_to_dev(disk)->devt = devt; + bdi_register_owner(disk->queue->backing_dev_info, + disk_to_dev(disk)); + blk_register_region(disk_devt(disk), disk->minors, NULL, + exact_match, exact_lock, disk); + } register_disk(parent, disk); blk_register_queue(disk); @@ -669,10 +687,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk) */ WARN_ON_ONCE(!blk_get_queue(disk->queue)); - retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, - "bdi"); - WARN_ON(retval); - disk_add_events(disk); blk_integrity_add(disk); } @@ -701,7 +715,8 @@ void del_gendisk(struct gendisk *disk) set_capacity(disk, 0); disk->flags &= ~GENHD_FL_UP; - sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); + if (!(disk->flags & GENHD_FL_HIDDEN)) + sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); if (disk->queue) { /* * Unregister bdi before releasing device numbers (as they can @@ -712,13 +727,15 @@ void del_gendisk(struct gendisk *disk) } else { WARN_ON(1); } - blk_unregister_region(disk_devt(disk), disk->minors); + + if (!(disk->flags & GENHD_FL_HIDDEN)) { + blk_unregister_region(disk_devt(disk), disk->minors); + kobject_put(disk->part0.holder_dir); + kobject_put(disk->slave_dir); + } part_stat_set_all(&disk->part0, 0); disk->part0.stamp = 0; - - kobject_put(disk->part0.holder_dir); - kobject_put(disk->slave_dir); if (!sysfs_deprecated) sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); @@ -781,6 +798,10 @@ struct gendisk *get_gendisk(dev_t devt, int *partno) spin_unlock_bh(&ext_devt_lock); } + if (unlikely(disk->flags & GENHD_FL_HIDDEN)) { + put_disk(disk); + disk = NULL; + } return disk; } EXPORT_SYMBOL(get_gendisk); @@ -1024,6 +1045,15 @@ static ssize_t disk_removable_show(struct device *dev, (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); } +static ssize_t disk_hidden_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%d\n", + (disk->flags & GENHD_FL_HIDDEN ? 1 : 0)); +} + static ssize_t disk_ro_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1061,6 +1091,7 @@ static ssize_t disk_discard_alignment_show(struct device *dev, static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL); static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL); static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL); +static DEVICE_ATTR(hidden, S_IRUGO, disk_hidden_show, NULL); static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL); static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL); static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL); @@ -1085,6 +1116,7 @@ static struct attribute *disk_attrs[] = { &dev_attr_range.attr, &dev_attr_ext_range.attr, &dev_attr_removable.attr, + &dev_attr_hidden.attr, &dev_attr_ro.attr, &dev_attr_size.attr, &dev_attr_alignment_offset.attr, -- cgit v1.2.3