linux-kernel - [PATCH v4 02/10] loop: Factor out setting loop device size

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Message-Id: <20200429140341.13294-3-maco@android.com>
Date:   Wed, 29 Apr 2020 16:03:33 +0200
From:   Martijn Coenen <maco@...roid.com>
To:     axboe@...nel.dk, hch@....de, ming.lei@...hat.com
Cc:     narayan@...gle.com, zezeozue@...gle.com, kernel-team@...roid.com,
        maco@...gle.com, bvanassche@....org, Chaitanya.Kulkarni@....com,
        jaegeuk@...nel.org, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, Martijn Coenen <maco@...roid.com>
Subject: [PATCH v4 02/10] loop: Factor out setting loop device size

This code is used repeatedly.

Signed-off-by: Martijn Coenen <maco@...roid.com>
---
 drivers/block/loop.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 396b8bd4d75c..6643e48ad71c 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -241,12 +241,29 @@ loop_validate_size(loff_t size)
 	return 0;
 }
 
+/**
+ * loop_set_size() - sets device size and notifies userspace
+ * @lo: struct loop_device to set the size for
+ * @size: new size of the loop device
+ *
+ * Callers must validate that the size passed into this function fits into
+ * a sector_t, eg using loop_validate_size()
+ */
+static void loop_set_size(struct loop_device *lo, loff_t size)
+{
+	struct block_device *bdev = lo->lo_device;
+
+	set_capacity(lo->lo_disk, size);
+	bd_set_size(bdev, size << SECTOR_SHIFT);
+	/* let user-space know about the new size */
+	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
+}
+
 static int
 figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
 {
 	int err;
 	loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
-	struct block_device *bdev = lo->lo_device;
 
 	err = loop_validate_size(size);
 	if (err)
@@ -256,10 +273,9 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
 		lo->lo_offset = offset;
 	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);
+
+	loop_set_size(lo, size);
+
 	return 0;
 }
 
@@ -1055,11 +1071,8 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 
 	loop_update_rotational(lo);
 	loop_update_dio(lo);
-	set_capacity(lo->lo_disk, size);
-	bd_set_size(bdev, size << 9);
 	loop_sysfs_init(lo);
-	/* let user-space know about the new size */
-	kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
+	loop_set_size(lo, size);
 
 	set_blocksize(bdev, S_ISBLK(inode->i_mode) ?
 		      block_size(inode->i_bdev) : PAGE_SIZE);
-- 
2.26.2.303.gf8c07b1a785-goog