1 files changed, 29 insertions, 32 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f47dccbda1d..747bb2af69d 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -162,12 +162,13 @@ static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
 
 static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
 {
-	loff_t size, loopsize;
+	loff_t loopsize;
 
 	/* Compute loopsize in bytes */
-	size = i_size_read(file->f_mapping->host);
-	loopsize = size - offset;
-	/* offset is beyond i_size, wierd but possible */
+	loopsize = i_size_read(file->f_mapping->host);
+	if (offset > 0)
+		loopsize -= offset;
+	/* offset is beyond i_size, weird but possible */
 	if (loopsize < 0)
 		return 0;
 
@@ -190,6 +191,7 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
 {
 	loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
 	sector_t x = (sector_t)size;
+	struct block_device *bdev = lo->lo_device;
 
 	if (unlikely((loff_t)x != size))
 		return -EFBIG;
@@ -198,6 +200,9 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
 	if (lo->lo_sizelimit != sizelimit)
 		lo->lo_sizelimit = sizelimit;
 	set_capacity(lo->lo_disk, x);
+	bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
+	/* let user-space know about the new size */
+	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
 	return 0;
 }
 
@@ -1091,10 +1096,10 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 		return err;
 
 	if (lo->lo_offset != info->lo_offset ||
-	    lo->lo_sizelimit != info->lo_sizelimit) {
+	    lo->lo_sizelimit != info->lo_sizelimit)
 		if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
 			return -EFBIG;
-	}
+
 	loop_config_discard(lo);
 
 	memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
@@ -1271,28 +1276,10 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
 
 static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev)
 {
-	int err;
-	sector_t sec;
-	loff_t sz;
-
-	err = -ENXIO;
 	if (unlikely(lo->lo_state != Lo_bound))
-		goto out;
-	err = figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
-	if (unlikely(err))
-		goto out;
-	sec = get_capacity(lo->lo_disk);
-	/* the width of sector_t may be narrow for bit-shift */
-	sz = sec;
-	sz <<= 9;
-	mutex_lock(&bdev->bd_mutex);
-	bd_set_size(bdev, sz);
-	/* let user-space know about the new size */
-	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
-	mutex_unlock(&bdev->bd_mutex);
+		return -ENXIO;
 
- out:
-	return err;
+	return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
 }
 
 static int lo_ioctl(struct block_device *bdev, fmode_t mode,
@@ -1845,11 +1832,15 @@ static int __init loop_init(void)
 		max_part = (1UL << part_shift) - 1;
 	}
 
-	if ((1UL << part_shift) > DISK_MAX_PARTS)
-		return -EINVAL;
+	if ((1UL << part_shift) > DISK_MAX_PARTS) {
+		err = -EINVAL;
+		goto misc_out;
+	}
 
-	if (max_loop > 1UL << (MINORBITS - part_shift))
-		return -EINVAL;
+	if (max_loop > 1UL << (MINORBITS - part_shift)) {
+		err = -EINVAL;
+		goto misc_out;
+	}
 
 	/*
 	 * If max_loop is specified, create that many devices upfront.
@@ -1867,8 +1858,10 @@ static int __init loop_init(void)
 		range = 1UL << MINORBITS;
 	}
 
-	if (register_blkdev(LOOP_MAJOR, "loop"))
-		return -EIO;
+	if (register_blkdev(LOOP_MAJOR, "loop")) {
+		err = -EIO;
+		goto misc_out;
+	}
 
 	blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
 				  THIS_MODULE, loop_probe, NULL, NULL);
@@ -1881,6 +1874,10 @@ static int __init loop_init(void)
 
 	printk(KERN_INFO "loop: module loaded\n");
 	return 0;
+
+misc_out:
+	misc_deregister(&loop_misc);
+	return err;
 }
 
 static int loop_exit_cb(int id, void *ptr, void *data)