block: Replace bi_integrity with bi_special

For commands like REQ_COPY we need a way to pass extra information along
with each bio. Like integrity metadata this information must be
available at the bottom of the stack so bi_private does not suffice.

Rename the existing bi_integrity field to bi_special and make it a union
so we can have different bio extensions for each class of command.

We previously used bi_integrity != NULL as a way to identify whether a
bio had integrity metadata or not. Introduce a REQ_INTEGRITY to be the
indicator now that bi_special can contain different things.

In addition, bio_integrity(bio) will now return a pointer to the
integrity payload (when applicable).

Signed-off-by: Martin K. Petersen <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
This commit is contained in:
Martin K. Petersen 2014-09-26 19:19:56 -04:00 • committed by Jens Axboe
commit 180b2f95dd
6 changed files with 36 additions and 27 deletions

View file

@ -129,11 +129,11 @@ interface for this is being worked on.
4.1 BIO
The data integrity patches add a new field to struct bio when
CONFIG_BLK_DEV_INTEGRITY is enabled. bio->bi_integrity is a pointer
to a struct bip which contains the bio integrity payload. Essentially
a bip is a trimmed down struct bio which holds a bio_vec containing
the integrity metadata and the required housekeeping information (bvec
pool, vector count, etc.)
CONFIG_BLK_DEV_INTEGRITY is enabled. bio_integrity(bio) returns a
pointer to a struct bip which contains the bio integrity payload.
Essentially a bip is a trimmed down struct bio which holds a bio_vec
containing the integrity metadata and the required housekeeping
information (bvec pool, vector count, etc.)
A kernel subsystem can enable data integrity protection on a bio by
calling bio_integrity_alloc(bio). This will allocate and attach the