[PATCH v2 0/3] Block integrity with flexible-offset PI

[Kanchan Joshi]

The block integrity subsystem can only work with PI placed in the first
bytes of the metadata buffer.

The series makes block-integrity support the flexible placement of PI.
And changes NVMe driver to make use of the new capability.

This helps to
(i) enable the more common case for NVMe (PI in last bytes is the norm)
(ii) reduce nop profile users (tried by Jens recently [1]).

/* For NS 4K+16b, 8b PI, last bytes */
Before:
# cat /sys/block/nvme0n1/integrity/format
nop

After:
# cat /sys/block/nvme0n1/integrity/format
T10-DIF-TYPE1-CRC

Changes since v1:
- Reworded commit messsage in patch 2 and 3 (hch)
- Variable initialization order change (hch)
- Collect reviewed-by

[1] https://lore.kernel.org/linux-block/20240111160226.1936351-1-axboe@kernel.dk/



Kanchan Joshi (3):
  block: refactor guard helpers
  block: support PI at non-zero offset within metadata
  nvme: allow integrity when PI is not in first bytes

 block/bio-integrity.c         |  1 +
 block/blk-integrity.c         |  1 +
 block/t10-pi.c                | 72 +++++++++++++++++++++++------------
 drivers/nvme/host/core.c      |  8 +++-
 drivers/nvme/host/nvme.h      |  1 +
 include/linux/blk-integrity.h |  1 +
 include/linux/blkdev.h        |  1 +
 7 files changed, 60 insertions(+), 25 deletions(-)

-- 
2.25.1