[PATCH v3 0/5] Add support for block disk resize notification

Allow block/genhd to notify user space about disk size changes using a
new helper set_capacity_revalidate_and_notify(), which is a wrapper
on top of set_capacity(). set_capacity_revalidate_and_notify() will only notify
iff the current capacity or the target capacity is not zero and the
capacity really changes.

Background:

As a part of a patch to allow sending the RESIZE event on disk capacity
change, Christoph (hch@lst.de) requested that the patch be made generic
and the hacks for virtio block and xen block devices be removed and
merged via a generic helper.

This series consists of 5 changes. The first one adds the basic
support for changing the size and notifying. The follow up patches
are per block subsystem changes. Other block drivers can add their
changes as necessary on top of this series. Since not all devices
are resizable, the default was to add a new API and let users
slowly convert over as needed.

Testing:
1. I did some basic testing with an NVME device, by resizing it in
the backend and ensured that udevd received the event.


Changelog v3:
- Repost after rebasing
- Trim details of the subsystem/files in the subject
Changelog v2:
- Rename disk_set_capacity to set_capacity_revalidate_and_notify
- set_capacity_revalidate_and_notify can call revalidate disk
  if needed, a new bool parameter is passed (suggested by Bob Liu)

Balbir Singh (5):
  block/genhd: Notify udev about capacity change
  virtio_blk.c: Convert to use set_capacity_revalidate_and_notify
  xen-blkfront.c: Convert to use set_capacity_revalidate_and_notify
  nvme: Convert to use set_capacity_revalidate_and_notify
  scsi: Convert to use set_capacity_revalidate_and_notify

 block/genhd.c                | 24 ++++++++++++++++++++++++
 drivers/block/virtio_blk.c   |  5 +----
 drivers/block/xen-blkfront.c |  6 +-----
 drivers/nvme/host/core.c     |  2 +-
 drivers/scsi/sd.c            |  3 ++-
 include/linux/genhd.h        |  2 ++
 6 files changed, 31 insertions(+), 11 deletions(-)

-- 
2.16.6