block: allocate the zone bitmaps lazily

Allocate the conventional zone bitmap and the sequential zone locking
bitmap only when we find a zone of the respective type.  This avoids
wasting memory on the conventional zone bitmap for devices that only
have sequential zones, and will also prepare for other future changes.

Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 9c39310..0131f9e 100644 (file)
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -342,6 +342,7 @@ struct blk_revalidate_zone_args {
        struct gendisk  *disk;
        unsigned long   *conv_zones_bitmap;
        unsigned long   *seq_zones_wlock;
+       unsigned int    nr_zones;
        sector_t        sector;
 };
 
@@ -385,8 +386,22 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
        /* Check zone type */
        switch (zone->type) {
        case BLK_ZONE_TYPE_CONVENTIONAL:
+               if (!args->conv_zones_bitmap) {
+                       args->conv_zones_bitmap =
+                               blk_alloc_zone_bitmap(q->node, args->nr_zones);
+                       if (!args->conv_zones_bitmap)
+                               return -ENOMEM;
+               }
+               set_bit(idx, args->conv_zones_bitmap);
+               break;
        case BLK_ZONE_TYPE_SEQWRITE_REQ:
        case BLK_ZONE_TYPE_SEQWRITE_PREF:
+               if (!args->seq_zones_wlock) {
+                       args->seq_zones_wlock =
+                               blk_alloc_zone_bitmap(q->node, args->nr_zones);
+                       if (!args->seq_zones_wlock)
+                               return -ENOMEM;
+               }
                break;
        default:
                pr_warn("%s: Invalid zone type 0x%x at sectors %llu\n",
@@ -394,37 +409,10 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
                return -ENODEV;
        }
 
-       if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
-               set_bit(idx, args->conv_zones_bitmap);
-
        args->sector += zone->len;
        return 0;
 }
 
-static int blk_update_zone_info(struct gendisk *disk, unsigned int nr_zones,
-                               struct blk_revalidate_zone_args *args)
-{
-       /*
-        * Ensure that all memory allocations in this context are done as
-        * if GFP_NOIO was specified.
-        */
-       unsigned int noio_flag = memalloc_noio_save();
-       struct request_queue *q = disk->queue;
-       int ret;
-
-       args->seq_zones_wlock = blk_alloc_zone_bitmap(q->node, nr_zones);
-       if (!args->seq_zones_wlock)
-               return -ENOMEM;
-       args->conv_zones_bitmap = blk_alloc_zone_bitmap(q->node, nr_zones);
-       if (!args->conv_zones_bitmap)
-               return -ENOMEM;
-
-       ret = disk->fops->report_zones(disk, 0, nr_zones,
-                                      blk_revalidate_zone_cb, args);
-       memalloc_noio_restore(noio_flag);
-       return ret;
-}
-
 /**
  * blk_revalidate_disk_zones - (re)allocate and initialize zone bitmaps
  * @disk:      Target disk
@@ -437,8 +425,10 @@ static int blk_update_zone_info(struct gendisk *disk, unsigned int nr_zones,
 int blk_revalidate_disk_zones(struct gendisk *disk)
 {
        struct request_queue *q = disk->queue;
-       unsigned int nr_zones = blkdev_nr_zones(disk);
-       struct blk_revalidate_zone_args args = { .disk = disk };
+       struct blk_revalidate_zone_args args = {
+               .disk           = disk,
+               .nr_zones       = blkdev_nr_zones(disk),
+       };
        int ret = 0;
 
        if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
@@ -449,12 +439,21 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
         * needs to be updated so that the sysfs exposed value is correct.
         */
        if (!queue_is_mq(q)) {
-               q->nr_zones = nr_zones;
+               q->nr_zones = args.nr_zones;
                return 0;
        }
 
-       if (nr_zones)
-               ret = blk_update_zone_info(disk, nr_zones, &args);
+       /*
+        * Ensure that all memory allocations in this context are done as
+        * if GFP_NOIO was specified.
+        */
+       if (args.nr_zones) {
+               unsigned int noio_flag = memalloc_noio_save();
+
+               ret = disk->fops->report_zones(disk, 0, args.nr_zones,
+                                              blk_revalidate_zone_cb, &args);
+               memalloc_noio_restore(noio_flag);
+       }
 
        /*
         * Install the new bitmaps, making sure the queue is stopped and
@@ -463,7 +462,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
         */
        blk_mq_freeze_queue(q);
        if (ret >= 0) {
-               q->nr_zones = nr_zones;
+               q->nr_zones = args.nr_zones;
                swap(q->seq_zones_wlock, args.seq_zones_wlock);
                swap(q->conv_zones_bitmap, args.conv_zones_bitmap);
                ret = 0;