From: Christoph Hellwig <hch@lst.de>
Date: Wed, 3 Mar 2021 16:51:29 +0000 (+0100)
Subject: block: merge disk_scan_partitions and blkdev_reread_part
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=refs%2Fheads%2Fpart-scan;p=users%2Fhch%2Fblock.git

block: merge disk_scan_partitions and blkdev_reread_part

Reuse disk_scan_partitions in the ioctl path instead of duplicating
the functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/block/genhd.c b/block/genhd.c
index 8c8f543572e6..39acb56bad5f 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -482,17 +482,25 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action)
 }
 EXPORT_SYMBOL_GPL(disk_uevent);
 
-static void disk_scan_partitions(struct gendisk *disk)
+/*
+ * Partitions are scanned on open when the GD_NEED_PART_SCAN flag is set, so
+ * force a scan by setting the flag and (re-)opening the device.
+ */
+int disk_scan_partitions(struct gendisk *disk)
 {
 	struct block_device *bdev;
 
-	if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
-		return;
+	if (!disk_part_scan_enabled(disk))
+		return -EINVAL;
+	if (!get_capacity(disk))
+		return 0;
 
 	set_bit(GD_NEED_PART_SCAN, &disk->state);
 	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
-	if (!IS_ERR(bdev))
-		blkdev_put(bdev, FMODE_READ);
+	if (IS_ERR(bdev))
+		return PTR_ERR(bdev);
+	blkdev_put(bdev, FMODE_READ);
+	return 0;
 }
 
 static void register_disk(struct device *parent, struct gendisk *disk,
diff --git a/block/ioctl.c b/block/ioctl.c
index ff241e663c01..b5e87bd8ac47 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -81,29 +81,6 @@ static int compat_blkpg_ioctl(struct block_device *bdev,
 }
 #endif
 
-static int blkdev_reread_part(struct block_device *bdev, fmode_t mode)
-{
-	struct block_device *tmp;
-
-	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev_is_partition(bdev))
-		return -EINVAL;
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-
-	/*
-	 * Reopen the device to revalidate the driver state and force a
-	 * partition rescan.
-	 */
-	mode &= ~FMODE_EXCL;
-	set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
-
-	tmp = blkdev_get_by_dev(bdev->bd_dev, mode, NULL);
-	if (IS_ERR(tmp))
-		return PTR_ERR(tmp);
-	blkdev_put(tmp, mode);
-	return 0;
-}
-
 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 		unsigned long arg, unsigned long flags)
 {
@@ -505,7 +482,11 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 		bdev->bd_bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 		return 0;
 	case BLKRRPART:
-		return blkdev_reread_part(bdev, mode);
+		if (!capable(CAP_SYS_ADMIN))
+			return -EACCES;
+		if (bdev_is_partition(bdev))
+			return -EINVAL;
+		return disk_scan_partitions(bdev->bd_disk);
 	case BLKTRACESTART:
 	case BLKTRACESTOP:
 	case BLKTRACETEARDOWN:
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index f364619092cc..f30c8e83311e 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -271,6 +271,7 @@ static inline sector_t get_capacity(struct gendisk *disk)
 	return bdev_nr_sectors(disk->part0);
 }
 
+int disk_scan_partitions(struct gendisk *disk);
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
 int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
 int blk_drop_partitions(struct block_device *bdev);