Introduce the elevator feature ELEVATOR_F_ZONED_BLOCK_DEV to indicate
that an elevator supports zoned block device write ordering control.
Mark the mq-deadline as supporting this feature which is implemented
using zone write locking. SCSI zoned block device scan and null_blk
device creation with zoned mode enabled are also modified to require
this feature using the helper blk_queue_required_elevator_features().
This requirement can always be satisfied as the mq-deadline scheduler is
always selected for in-kernel compilation when CONFIG_BLK_DEV_ZONED
(zoned block device support) is enabled.
Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
---
block/mq-deadline.c | 1 +
drivers/block/null_blk_main.c | 5 +++++
drivers/scsi/sd_zbc.c | 2 ++
include/linux/elevator.h | 7 +++++++
4 files changed, 15 insertions(+)
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 2a2a2e82832e..95e03408f2ac 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -795,6 +795,7 @@ static struct elevator_type mq_deadline = {
.elevator_attrs = deadline_attrs,
.elevator_name = "mq-deadline",
.elevator_alias = "deadline",
+ .elevator_features = ELEVATOR_F_ZONED_BLOCK_DEV,
.elevator_owner = THIS_MODULE,
};
MODULE_ALIAS("mq-deadline-iosched");
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 99c56d72ff78..253bb7b4443e 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1538,6 +1538,9 @@ static int null_gendisk_register(struct nullb *nullb)
if (ret != 0)
return ret;
+
+ blk_queue_required_elevator_features(disk->queue,
+ ELEVATOR_F_ZONED_BLOCK_DEV);
}
add_disk(disk);
@@ -1691,6 +1694,8 @@ static int null_add_dev(struct nullb_device *dev)
blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects);
nullb->q->limits.zoned = BLK_ZONED_HM;
blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, nullb->q);
+ blk_queue_required_elevator_features(nullb->q,
+ ELEVATOR_F_ZONED_BLOCK_DEV);
}
nullb->q->queuedata = nullb;
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 367614f0e34f..983f5d0be902 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -490,6 +490,8 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
goto err;
/* The drive satisfies the kernel restrictions: set it up */
+ blk_queue_required_elevator_features(sdkp->disk->queue,
+ ELEVATOR_F_ZONED_BLOCK_DEV);
blk_queue_chunk_sectors(sdkp->disk->queue,
logical_to_sectors(sdkp->device, zone_blocks));
blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, sdkp->disk->queue);
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index a99ca9979d71..2b667cb23fc0 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -166,5 +166,12 @@ extern struct request *elv_rb_find(struct rb_root *, sector_t);
#define rq_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
#define rq_fifo_clear(rq) list_del_init(&(rq)->queuelist)
+/*
+ * Elevator features.
+ */
+
+/* Supports zoned block devices sequential write */
+#define ELEVATOR_F_ZONED_BLOCK_DEV (1UL << 0)
+
#endif /* CONFIG_BLOCK */
#endif
--
2.21.0
