block: Cleanup set_capacity()/bdev_set_nr_sectors()

The code for setting a block device capacity (bd_nr_sectors field of
struct block_device) is duplicated in set_capacity() and
bdev_set_nr_sectors(). Clean this up by making bdev_set_nr_sectors()
a block layer internal function defined in block/bdev.c instead of
having this function statically defined in block/partitions/core.c.
With this change, set_capacity() implementation can be simplified to
only calling bdev_set_nr_sectors().

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230424131318.79935-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: damien-lemoal

block/bdev.c

@@ -428,6 +428,14 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 	return bdev;
 }
 
+void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
+{
+	spin_lock(&bdev->bd_size_lock);
+	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
+	bdev->bd_nr_sectors = sectors;
+	spin_unlock(&bdev->bd_size_lock);
+}
+
 void bdev_add(struct block_device *bdev, dev_t dev)
 {
 	bdev->bd_dev = dev;

block/blk.h

@@ -419,6 +419,8 @@ int bdev_resize_partition(struct gendisk *disk, int partno, sector_t start,
 		sector_t length);
 void blk_drop_partitions(struct gendisk *disk);
 
+void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors);
+
 struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 		struct lock_class_key *lkclass);
 

block/genhd.c

@@ -57,12 +57,7 @@ static DEFINE_IDA(ext_devt_ida);
 
 void set_capacity(struct gendisk *disk, sector_t sectors)
 {
-	struct block_device *bdev = disk->part0;
-
-	spin_lock(&bdev->bd_size_lock);
-	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
-	bdev->bd_nr_sectors = sectors;
-	spin_unlock(&bdev->bd_size_lock);
+	bdev_set_nr_sectors(disk->part0, sectors);
 }
 EXPORT_SYMBOL(set_capacity);
 

block/partitions/core.c

@@ -85,14 +85,6 @@ static int (*check_part[])(struct parsed_partitions *) = {
 	NULL
 };
 
-static void bdev_set_nr_sectors(struct block_device *bdev, sector_t sectors)
-{
-	spin_lock(&bdev->bd_size_lock);
-	i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
-	bdev->bd_nr_sectors = sectors;
-	spin_unlock(&bdev->bd_size_lock);
-}
-
 static struct parsed_partitions *allocate_partitions(struct gendisk *hd)
 {
 	struct parsed_partitions *state;