block, libnvdimm, nvme: provide a built-in blk_integrity nop profile

The libnvidmm-btt and nvme drivers use blk_integrity to reserve space
for per-sector metadata, but sometimes without protection checksums.
This property is generically useful, so teach the block core to
internally specify a nop profile if one is not provided at registration
time.

Cc: Keith Busch <keith.busch@intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
[hch: kill the local nvme nop profile as well]
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 5d339ae64d56..d69c5c79f98e 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -384,6 +384,17 @@ static struct kobj_type integrity_ktype = {
         .sysfs_ops      = &integrity_ops,
 };
 
+static int blk_integrity_nop_fn(struct blk_integrity_iter *iter)
+{
+        return 0;
+}
+
+static struct blk_integrity_profile nop_profile = {
+        .name = "nop",
+        .generate_fn = blk_integrity_nop_fn,
+        .verify_fn = blk_integrity_nop_fn,
+};
+
 /**
  * blk_integrity_register - Register a gendisk as being integrity-capable
  * @disk:       struct gendisk pointer to make integrity-aware
@@ -402,7 +413,7 @@ void blk_integrity_register(struct gendisk *disk, struct blk_integrity *template
         bi->flags = BLK_INTEGRITY_VERIFY | BLK_INTEGRITY_GENERATE |
                 template->flags;
         bi->interval_exp = ilog2(queue_logical_block_size(disk->queue));
-        bi->profile = template->profile;
+        bi->profile = template->profile ? template->profile : &nop_profile;
         bi->tuple_size = template->tuple_size;
         bi->tag_size = template->tag_size;