fix and cleanup discard_alignment handling

[Christoph Hellwig]

Hi all,

the somewhat confusing name of the discard_alignment queue limit, that
really is an offset for the discard granularity mislead a lot of driver
authors to set it to an incorrect value.  This series tries to fix up
all these cases.

Diffstat:
 arch/um/drivers/ubd_kern.c         |    1 -
 drivers/block/loop.c               |    1 -
 drivers/block/nbd.c                |    3 ---
 drivers/block/null_blk/main.c      |    1 -
 drivers/block/rnbd/rnbd-srv-dev.h  |    2 +-
 drivers/block/virtio_blk.c         |    7 ++++---
 drivers/block/xen-blkback/xenbus.c |    4 ++--
 drivers/md/dm-zoned-target.c       |    2 +-
 drivers/md/raid5.c                 |    1 -
 drivers/nvme/host/core.c           |    1 -
 drivers/s390/block/dasd_fba.c      |    1 -
 11 files changed, 8 insertions(+), 16 deletions(-)