[PATCH 2/3] block: Introduce the BLK_FEAT_CALLS_BIO_SPLIT_TO_LIMITS flag

[Bart Van Assche <bvanassche@acm.org>]

Introduce a flag that indicates whether or not bio_split_to_limits() is
called while processing a bio. Set this flag from inside
blk_mq_alloc_queue() because bio_split_to_limits() is called for all
request-based block drivers. This patch prepares for modifying when
__submit_bio() calls blk_crypto_bio_prep().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-mq.c         | 3 ++-
 include/linux/blkdev.h | 6 +++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 532acdbe9e16..ab2fbc895a98 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4411,7 +4411,8 @@ struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set,
 
 	if (!lim)
 		lim = &default_lim;
-	lim->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT;
+	lim->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT |
+		BLK_FEAT_CALLS_BIO_SPLIT_TO_LIMITS;
 	if (set->nr_maps > HCTX_TYPE_POLL)
 		lim->features |= BLK_FEAT_POLL;
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a51f92b6c340..108f70aa4d15 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -340,13 +340,17 @@ typedef unsigned int __bitwise blk_features_t;
 #define BLK_FEAT_ATOMIC_WRITES \
 	((__force blk_features_t)(1u << 16))
 
+/* bio_split_to_limits() is called while processing a bio */
+#define BLK_FEAT_CALLS_BIO_SPLIT_TO_LIMITS ((__force blk_features_t)(1u << 17))
+
 /*
  * Flags automatically inherited when stacking limits.
  */
 #define BLK_FEAT_INHERIT_MASK \
 	(BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA | BLK_FEAT_ROTATIONAL | \
 	 BLK_FEAT_STABLE_WRITES | BLK_FEAT_ZONED | \
-	 BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE)
+	 BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE | \
+	 BLK_FEAT_CALLS_BIO_SPLIT_TO_LIMITS)
 
 /* internal flags in queue_limits.flags */
 typedef unsigned int __bitwise blk_flags_t;