We now can support blocksizes larger than PAGE_SIZE, so lift
the restriction up to the max supported page cache order and
just bake this into a common helper used by the block layer.

We bound ourselves to 64k as a sensible limit. The hard limit,
however is 1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER).

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
  block/bdev.c           |  5 ++---
  include/linux/blkdev.h | 11 ++++++++++-
  2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index 167d82b46781..b57dc4bff81b 100644
--- a/block/bdev.c
+++ b/block/bdev.c

@@ -157,8 +157,7 @@ int set_blocksize(struct file *file, int size)
  	struct inode *inode = file->f_mapping->host;
  	struct block_device *bdev = I_BDEV(inode);
  
-	/* Size must be a power of two, and between 512 and PAGE_SIZE */
-	if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
+	if (blk_validate_block_size(size))
  		return -EINVAL;
  
  	/* Size cannot be smaller than the size supported by the device */

@@ -185,7 +184,7 @@ int sb_set_blocksize(struct super_block *sb, int size)
  	if (set_blocksize(sb->s_bdev_file, size))
  		return 0;
  	/* If we get here, we know size is power of two
-	 * and it's value is between 512 and PAGE_SIZE */
+	 * and its value is larger than 512 */
  	sb->s_blocksize = size;
  	sb->s_blocksize_bits = blksize_bits(size);
  	return sb->s_blocksize;

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 08a727b40816..a7303a55ed2a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h

@@ -269,10 +269,19 @@ static inline dev_t disk_devt(struct gendisk *disk)
  	return MKDEV(disk->major, disk->first_minor);
  }
  
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * The hard limit is (1 << (PAGE_SHIFT + MAX_PAGECACHE_ORDER).