[PATCH V3 0/3] block: fix discard merge for single max discard segment

[Ming Lei <ming.lei@redhat.com>]

Hello,

The 1st patch checks max discard segment limit in request merge code,
and one discard request failure is fixed for virtio_blk.

The 2nd patch fixes handling of single max discard segment for virtio_blk,
and potential memory corruption is fixed.

The 3rd patch renames the confusing blk_discard_mergable().

The biggest problem is that virtio_blk handles discard request in
multi-range style, however it(at least qemu) may claim that multi range
discard isn't supported by returning 1 for max discard segment.

V3:
	- one patch style change in patch 1, as suggested by Christoph
	- add reviewed-by tag

V2:
	- add comment
	- warn on mismatched bios and discard segment number
	- rename blk_discard_mergable


Ming Lei (3):
  block: respect queue limit of max discard segment
  block: virtio_blk: fix handling single range discard request
  block: rename blk_discard_mergable as blk_discard_support_multi_range

 block/blk-merge.c          | 22 ++++++++++++++++------
 drivers/block/virtio_blk.c | 31 +++++++++++++++++++++++--------
 2 files changed, 39 insertions(+), 14 deletions(-)

Cc: Christoph Hellwig <hch@lst.de>
Cc: Changpeng Liu <changpeng.liu@intel.com>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
-- 
2.25.2