[PATCH v5 04/10] block: Modify revalidate zones

[Johannes Thumshirn <johannes.thumshirn@xxxxxxx>]

From: Damien Le Moal <damien.lemoal@xxxxxxx>

Modify the interface of blk_revalidate_disk_zones() to add an optional
revalidation callback function that a driver can use to extend checks and
processing done during zone revalidation. The callback, if defined, is
executed time after all zones are inspected and with the queue frozen.
blk_revalidate_disk_zones() is renamed as __blk_revalidate_disk_zones()
and blk_revalidate_disk_zones() implemented as an inline function calling
__blk_revalidate_disk_zones() without no revalidation callback specified,
resulting in an unchanged behavior for all callers of
blk_revalidate_disk_zones().

Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
---
 block/blk-zoned.c      | 19 ++++++++++++++-----
 include/linux/blkdev.h | 10 +++++++++-
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 00b025b8b7c0..6c37fec6859b 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -437,20 +437,27 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
 }
 
 /**
- * blk_revalidate_disk_zones - (re)allocate and initialize zone bitmaps
- * @disk:	Target disk
+ * __blk_revalidate_disk_zones - (re)allocate and initialize zone bitmaps
+ * @disk:		Target disk
+ * @revalidate_cb:	LLD callback
+ * @revalidate_data:	LLD callback argument
  *
  * Helper function for low-level device drivers to (re) allocate and initialize
  * a disk request queue zone bitmaps. This functions should normally be called
  * within the disk ->revalidate method for blk-mq based drivers.  For BIO based
  * drivers only q->nr_zones needs to be updated so that the sysfs exposed value
  * is correct.
+ * If the @revalidate_cb callback function is not NULL, the callback will be
+ * executed with the device request queue frozen after all zones have been
+ * checked.
  */
-int blk_revalidate_disk_zones(struct gendisk *disk)
+int __blk_revalidate_disk_zones(struct gendisk *disk,
+				revalidate_zones_cb revalidate_cb,
+				void *revalidate_data)
 {
 	struct request_queue *q = disk->queue;
 	struct blk_revalidate_zone_args args = {
-		.disk		= disk,
+		.disk			= disk,
 	};
 	unsigned int noio_flag;
 	int ret;
@@ -480,6 +487,8 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
 		q->nr_zones = args.nr_zones;
 		swap(q->seq_zones_wlock, args.seq_zones_wlock);
 		swap(q->conv_zones_bitmap, args.conv_zones_bitmap);
+		if (revalidate_cb)
+			revalidate_cb(disk, revalidate_data);
 		ret = 0;
 	} else {
 		pr_warn("%s: failed to revalidate zones\n", disk->disk_name);
@@ -491,4 +500,4 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
 	kfree(args.conv_zones_bitmap);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(blk_revalidate_disk_zones);
+EXPORT_SYMBOL_GPL(__blk_revalidate_disk_zones);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e591b22ace03..a730cacda0f7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -353,6 +353,8 @@ struct queue_limits {
 typedef int (*report_zones_cb)(struct blk_zone *zone, unsigned int idx,
 			       void *data);
 
+typedef void (*revalidate_zones_cb)(struct gendisk *disk, void *data);
+
 #ifdef CONFIG_BLK_DEV_ZONED
 
 #define BLK_ALL_ZONES  ((unsigned int)-1)
@@ -362,7 +364,13 @@ unsigned int blkdev_nr_zones(struct gendisk *disk);
 extern int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 			    sector_t sectors, sector_t nr_sectors,
 			    gfp_t gfp_mask);
-extern int blk_revalidate_disk_zones(struct gendisk *disk);
+int __blk_revalidate_disk_zones(struct gendisk *disk,
+				revalidate_zones_cb revalidate_cb,
+				void *revalidate_data);
+static inline int blk_revalidate_disk_zones(struct gendisk *disk)
+{
+	return __blk_revalidate_disk_zones(disk, NULL, NULL);
+}
 
 extern int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
 				     unsigned int cmd, unsigned long arg);
-- 
2.24.1