In preparation for fixing device mapper zone write handling, introduce
the helper function bio_needs_zone_write_plugging() to test if a BIO
requires handling through zone write plugging. This function returns
true for any write operation to a zoned block device. For zone append
opertions, true is returned only if the device requires zone append
emulation with regular writes.
Fixes: f211268ed1f9 ("dm: Use the block layer zone append emulation")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
---
block/blk-zoned.c | 40 ++++++++++++++++++++++++++++++++++++++++
include/linux/blkdev.h | 9 +++++++++
2 files changed, 49 insertions(+)
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 55e64ca869d7..9d38b94cad0d 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -1129,6 +1129,46 @@ static void blk_zone_wplug_handle_native_zone_append(struct bio *bio)
disk_put_zone_wplug(zwplug);
}
+/**
+ * bio_needs_zone_write_plugging - Check if a BIO needs to be handled with zone
+ * write plugging
+ * @bio: The BIO being submitted
+ *
+ * Return true whenever @bio execution needs to be handled through zone
+ * write plugging. Return false otherwise.
+ */
+bool bio_needs_zone_write_plugging(struct bio *bio)
+{
+ enum req_op op = bio_op(bio);
+
+ if (!bdev_is_zoned(bio->bi_bdev) || !op_is_write(op))
+ return false;
+
+ /* Already handled ? */
+ if (bio_flagged(bio, BIO_ZONE_WRITE_PLUGGING))
+ return false;
+
+ /* Ignore empty flush */
+ if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
+ return false;
+
+ /*
+ * Regular writes and write zeroes need to be handled through zone
+ * write plugging. Zone append operations only need zone write plugging
+ * if they are emulated.
+ */
+ switch (op) {
+ case REQ_OP_ZONE_APPEND:
+ return bdev_emulates_zone_append(bio->bi_bdev);
+ case REQ_OP_WRITE:
+ case REQ_OP_WRITE_ZEROES:
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL_GPL(bio_needs_zone_write_plugging);
+
/**
* blk_zone_plug_bio - Handle a zone write BIO with zone write plugging
* @bio: The BIO being submitted
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c2b3ddea8b6d..d455057bfaa3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -848,6 +848,9 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk)
{
return disk->nr_zones;
}
+
+bool bio_needs_zone_write_plugging(struct bio *bio);
+
bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs);
/**
@@ -877,6 +880,12 @@ static inline unsigned int disk_nr_zones(struct gendisk *disk)
{
return 0;
}
+
+static inline bool bio_needs_zone_write_plugging(struct bio *bio)
+{
+ return false;
+}
+
static inline bool blk_zone_plug_bio(struct bio *bio, unsigned int nr_segs)
{
return false;
--
2.49.0
