[PATCH] ublk: use global index for reported zones

[lirongqing <lirongqing@baidu.com>]

From: Li RongQing <lirongqing@baidu.com>

ublk_report_zones() may split a zone report into multiple requests when
the number of zones exceeds the temporary buffer capacity. The index
passed to disk_report_zone() must refer to the zone position in the
whole report, rather than the position within the current request.

Currently, the per-request loop index is used as the callback index,
causing each chunk after the first one to restart from zero. This can
make userspace callbacks receive duplicate zone indices and may result
in blk_revalidate_disk_zones() updating incorrect entries in its zone
state array.

Use the number of zones already reported as the base index for each
request so that zone indices remain continuous across all chunks.

Fixes: 29802d7ca33b ("ublk: enable zoned storage support")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 drivers/block/ublk_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 66eb55e..007e703 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -649,6 +649,7 @@ static int ublk_report_zones(struct gendisk *disk, sector_t sector,
 		unsigned int remaining_zones = nr_zones - done_zones;
 		unsigned int zones_in_request =
 			min_t(unsigned int, remaining_zones, max_zones_per_request);
+		unsigned int batch_start = done_zones;
 		struct request *req;
 		struct ublk_zoned_report_desc desc;
 		blk_status_t status;
@@ -687,7 +688,7 @@ static int ublk_report_zones(struct gendisk *disk, sector_t sector,
 			if (!zone->len)
 				break;
 
-			ret = disk_report_zone(disk, zone, i, args);
+			ret = disk_report_zone(disk, zone, batch_start + i, args);
 			if (ret)
 				goto out;
 
-- 
2.9.4