block: rework zone reporting
Avoid the need to allocate a potentially large array of struct blk_zone
in the block layer by switching the ->report_zones method interface to
a callback model. Now the caller simply supplies a callback that is
executed on each reported zone, and private data for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
index 00696f1..d4d88b5 100644
--- a/drivers/block/null_blk_zoned.c
+++ b/drivers/block/null_blk_zoned.c
@@ -67,21 +67,34 @@ void null_zone_exit(struct nullb_device *dev)
}
int null_report_zones(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones)
+ unsigned int nr_zones, report_zones_cb cb, void *data)
{
struct nullb *nullb = disk->private_data;
struct nullb_device *dev = nullb->dev;
- unsigned int zno, nrz = 0;
+ unsigned int first_zone, i;
+ struct blk_zone zone;
+ int error;
- zno = null_zone_no(dev, sector);
- if (zno < dev->nr_zones) {
- nrz = min_t(unsigned int, *nr_zones, dev->nr_zones - zno);
- memcpy(zones, &dev->zones[zno], nrz * sizeof(struct blk_zone));
+ first_zone = null_zone_no(dev, sector);
+ if (first_zone >= dev->nr_zones)
+ return 0;
+
+ nr_zones = min(nr_zones, dev->nr_zones - first_zone);
+ for (i = 0; i < nr_zones; i++) {
+ /*
+ * Stacked DM target drivers will remap the zone information by
+ * modifying the zone information passed to the report callback.
+ * So use a local copy to avoid corruption of the device zone
+ * array.
+ */
+ memcpy(&zone, &dev->zones[first_zone + i],
+ sizeof(struct blk_zone));
+ error = cb(&zone, i, data);
+ if (error)
+ return error;
}
- *nr_zones = nrz;
-
- return 0;
+ return nr_zones;
}
size_t null_zone_valid_read_len(struct nullb *nullb,
