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@xxxxxx) 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 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 drivers/block/virtio_blk.c: Convert to use set_capacity_revalidate_and_notify drivers/block/xen-blkfront.c: Convert to use set_capacity_revalidate_and_notify drivers/nvme/host/core.c: Convert to use set_capacity_revalidate_and_notify drivers/scsi/sd.c: 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