[PATCH 7/8] block: factor out a part_devt helper

Christoph Hellwig
2021-05-12T06:19:25Z

Add a helper to find the dev_t for a disk + partno tuple.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/genhd.c | 25 +++++++++++++++++--------
include/linux/genhd.h | 1 +
init/do_mounts.c | 10 ++--------
3 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 8b88e99f6675..14fd777811fe 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1251,6 +1251,19 @@ static int __init proc_genhd_init(void)
module_init(proc_genhd_init);
#endif /* CONFIG_PROC_FS */

+dev_t part_devt(struct gendisk *disk, u8 partno)
+{
+ struct block_device *part = bdget_disk(disk, partno);
+ dev_t devt = 0;
+
+ if (part) {
+ devt = part->bd_dev;
+ bdput(part);
+ }
+
+ return devt;
+}
+
dev_t blk_lookup_devt(const char *name, int partno)
{
dev_t devt = MKDEV(0, 0);
@@ -1260,7 +1273,6 @@ dev_t blk_lookup_devt(const char *name, int partno)
class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
while ((dev = class_dev_iter_next(&iter))) {
struct gendisk *disk = dev_to_disk(dev);
- struct block_device *part;

if (strcmp(dev_name(dev), name))
continue;
@@ -1271,13 +1283,10 @@ dev_t blk_lookup_devt(const char *name, int partno)
*/
devt = MKDEV(MAJOR(dev->devt),
MINOR(dev->devt) + partno);
- break;
- }
- part = bdget_disk(disk, partno);
- if (part) {
- devt = part->bd_dev;
- bdput(part);
- break;
+ } else {
+ devt = part_devt(disk, partno);
+ if (devt)
+ break;
}
}
class_dev_iter_exit(&iter);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 74fd28ddac70..4c4d903caa09 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -312,6 +312,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,

extern struct rw_semaphore bdev_lookup_sem;

+dev_t part_devt(struct gendisk *disk, u8 partno);
dev_t blk_lookup_devt(const char *name, int partno);
void blk_request_module(dev_t devt);
#ifdef CONFIG_BLOCK
diff --git a/init/do_mounts.c b/init/do_mounts.c
index a78e44ee6adb..74aede860de7 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -133,14 +133,8 @@ static dev_t devt_from_partuuid(const char *uuid_str)
* Attempt to find the requested partition by adding an offset
* to the partition number found by UUID.
*/
- struct block_device *part;
-
- part = bdget_disk(dev_to_disk(dev),
- dev_to_bdev(dev)->bd_partno + offset);
- if (part) {
- devt = part->bd_dev;
- bdput(part);
- }
+ devt = part_devt(dev_to_disk(dev),
+ dev_to_bdev(dev)->bd_partno + offset);
} else {
devt = dev->devt;
}
--
2.30.2