block: use struct parsed_partitions *state universally in partition check code

Make the following changes to partition check code.

* Add ->bdev to struct parsed_partitions.

* Introduce read_part_sector() which is a simple wrapper around
  read_dev_sector() which takes struct parsed_partitions *state
  instead of @bdev.

* For functions which used to take @state and @bdev, drop @bdev.  For
  functions which used to take @bdev, replace it with @state.

* While updating, drop superflous checks on NULL state/bdev in ldm.c.

This cleans up the API a bit and enables better handling of IO errors
during partition check as the generic partition check code now has
much better visibility into what went wrong in the low level code
paths.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/partitions/check.h b/fs/partitions/check.h
index 98dbe1a..4b31a97 100644
--- a/fs/partitions/check.h
+++ b/fs/partitions/check.h
@@ -6,6 +6,7 @@
  * description.
  */
 struct parsed_partitions {
+	struct block_device *bdev;
 	char name[BDEVNAME_SIZE];
 	struct {
 		sector_t from;
@@ -16,6 +17,12 @@ struct parsed_partitions {
 	int limit;
 };
 
+static inline void *read_part_sector(struct parsed_partitions *state,
+				     sector_t n, Sector *p)
+{
+	return read_dev_sector(state->bdev, n, p);
+}
+
 static inline void
 put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
 {