From bbec0270bdd887f96377065ee38b8848b5afa395 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 29 Nov 2012 12:31:52 -0800
Subject: [PATCH] blkdev_max_block: make private to fs/buffer.c

We really don't want to look at the block size for the raw block device
accesses in fs/block-dev.c, because it may be changing from under us.
So get rid of the max_block logic entirely, since the caller should
already have done it anyway.

That leaves the only user of this function in fs/buffer.c, so move the
whole function there and make it static.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/block_dev.c     | 55 +---------------------------------------------
 fs/buffer.c        | 14 +++++++++++-
 include/linux/fs.h |  1 -
 3 files changed, 14 insertions(+), 56 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 47a949d8a07e..a1e09b4fe1ba 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -70,19 +70,6 @@ static void bdev_inode_switch_bdi(struct inode *inode,
 	spin_unlock(&dst->wb.list_lock);
 }
 
-sector_t blkdev_max_block(struct block_device *bdev)
-{
-	sector_t retval = ~((sector_t)0);
-	loff_t sz = i_size_read(bdev->bd_inode);
-
-	if (sz) {
-		unsigned int size = block_size(bdev);
-		unsigned int sizebits = blksize_bits(size);
-		retval = (sz >> sizebits);
-	}
-	return retval;
-}
-
 /* Kill _all_ buffers and pagecache , dirty or not.. */
 void kill_bdev(struct block_device *bdev)
 {
@@ -163,52 +150,12 @@ static int
 blkdev_get_block(struct inode *inode, sector_t iblock,
 		struct buffer_head *bh, int create)
 {
-	if (iblock >= blkdev_max_block(I_BDEV(inode))) {
-		if (create)
-			return -EIO;
-
-		/*
-		 * for reads, we're just trying to fill a partial page.
-		 * return a hole, they will have to call get_block again
-		 * before they can fill it, and they will get -EIO at that
-		 * time
-		 */
-		return 0;
-	}
 	bh->b_bdev = I_BDEV(inode);
 	bh->b_blocknr = iblock;
 	set_buffer_mapped(bh);
 	return 0;
 }
 
-static int
-blkdev_get_blocks(struct inode *inode, sector_t iblock,
-		struct buffer_head *bh, int create)
-{
-	sector_t end_block = blkdev_max_block(I_BDEV(inode));
-	unsigned long max_blocks = bh->b_size >> inode->i_blkbits;
-
-	if ((iblock + max_blocks) > end_block) {
-		max_blocks = end_block - iblock;
-		if ((long)max_blocks <= 0) {
-			if (create)
-				return -EIO;	/* write fully beyond EOF */
-			/*
-			 * It is a read which is fully beyond EOF.  We return
-			 * a !buffer_mapped buffer
-			 */
-			max_blocks = 0;
-		}
-	}
-
-	bh->b_bdev = I_BDEV(inode);
-	bh->b_blocknr = iblock;
-	bh->b_size = max_blocks << inode->i_blkbits;
-	if (max_blocks)
-		set_buffer_mapped(bh);
-	return 0;
-}
-
 static ssize_t
 blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 			loff_t offset, unsigned long nr_segs)
@@ -217,7 +164,7 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 	struct inode *inode = file->f_mapping->host;
 
 	return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset,
-				    nr_segs, blkdev_get_blocks, NULL, NULL, 0);
+				    nr_segs, blkdev_get_block, NULL, NULL, 0);
 }
 
 int __sync_blockdev(struct block_device *bdev, int wait)
diff --git a/fs/buffer.c b/fs/buffer.c
index 28a74ff5324b..3586fb05c8ce 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -911,6 +911,18 @@ link_dev_buffers(struct page *page, struct buffer_head *head)
 	attach_page_buffers(page, head);
 }
 
+static sector_t blkdev_max_block(struct block_device *bdev, unsigned int size)
+{
+	sector_t retval = ~((sector_t)0);
+	loff_t sz = i_size_read(bdev->bd_inode);
+
+	if (sz) {
+		unsigned int sizebits = blksize_bits(size);
+		retval = (sz >> sizebits);
+	}
+	return retval;
+}
+
 /*
  * Initialise the state of a blockdev page's buffers.
  */ 
@@ -921,7 +933,7 @@ init_page_buffers(struct page *page, struct block_device *bdev,
 	struct buffer_head *head = page_buffers(page);
 	struct buffer_head *bh = head;
 	int uptodate = PageUptodate(page);
-	sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode));
+	sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode), size);
 
 	do {
 		if (!buffer_mapped(bh)) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 44f288e9726d..75fe9a134803 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2047,7 +2047,6 @@ extern void unregister_blkdev(unsigned int, const char *);
 extern struct block_device *bdget(dev_t);
 extern struct block_device *bdgrab(struct block_device *bdev);
 extern void bd_set_size(struct block_device *, loff_t size);
-extern sector_t blkdev_max_block(struct block_device *bdev);
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern void invalidate_bdev(struct block_device *);
-- 
2.20.1