minor cleanups to bdev_disk_changed

minor cleanups to bdev_disk_changed

[Christoph Hellwig]

Hi Jens,

two patches to clean up bdev_disk_changed that got lost large merge
window to avoid merge conflicts.

[PATCH 1/2] block: move bdev_disk_changed

[Christoph Hellwig]

Move bdev_disk_changed to block/partitions/core.c, together with the
rest of the partition scanning code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c | 55 ++++++++++++++++++++++++++++++++++++++++-
 fs/block_dev.c          | 53 ---------------------------------------
 include/linux/genhd.h   |  1 -
 3 files changed, 54 insertions(+), 55 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 186d4fbd9f09..b79785f7027c 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -596,7 +596,7 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 	return true;
 }
 
-int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
+static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 {
 	struct parsed_partitions *state;
 	int ret = -EAGAIN, p;
@@ -657,6 +657,59 @@ int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 	return ret;
 }
 
+int bdev_disk_changed(struct block_device *bdev, bool invalidate)
+{
+	struct gendisk *disk = bdev->bd_disk;
+	int ret = 0;
+
+	lockdep_assert_held(&disk->open_mutex);
+
+	if (!(disk->flags & GENHD_FL_UP))
+		return -ENXIO;
+
+rescan:
+	if (disk->open_partitions)
+		return -EBUSY;
+	sync_blockdev(bdev);
+	invalidate_bdev(bdev);
+	blk_drop_partitions(disk);
+
+	clear_bit(GD_NEED_PART_SCAN, &disk->state);
+
+	/*
+	 * Historically we only set the capacity to zero for devices that
+	 * support partitions (independ of actually having partitions created).
+	 * Doing that is rather inconsistent, but changing it broke legacy
+	 * udisks polling for legacy ide-cdrom devices.  Use the crude check
+	 * below to get the sane behavior for most device while not breaking
+	 * userspace for this particular setup.
+	 */
+	if (invalidate) {
+		if (disk_part_scan_enabled(disk) ||
+		    !(disk->flags & GENHD_FL_REMOVABLE))
+			set_capacity(disk, 0);
+	}
+
+	if (get_capacity(disk)) {
+		ret = blk_add_partitions(disk, bdev);
+		if (ret == -EAGAIN)
+			goto rescan;
+	} else if (invalidate) {
+		/*
+		 * Tell userspace that the media / partition table may have
+		 * changed.
+		 */
+		kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+	}
+
+	return ret;
+}
+/*
+ * Only exported for loop and dasd for historic reasons.  Don't use in new
+ * code!
+ */
+EXPORT_SYMBOL_GPL(bdev_disk_changed);
+
 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
 {
 	struct address_space *mapping = state->bdev->bd_inode->i_mapping;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index ac9b3c158a77..5b3a73ecb696 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1242,59 +1242,6 @@ static void blkdev_flush_mapping(struct block_device *bdev)
 	bdev_write_inode(bdev);
 }
 
-int bdev_disk_changed(struct block_device *bdev, bool invalidate)
-{
-	struct gendisk *disk = bdev->bd_disk;
-	int ret = 0;
-
-	lockdep_assert_held(&disk->open_mutex);
-
-	if (!(disk->flags & GENHD_FL_UP))
-		return -ENXIO;
-
-rescan:
-	if (disk->open_partitions)
-		return -EBUSY;
-	sync_blockdev(bdev);
-	invalidate_bdev(bdev);
-	blk_drop_partitions(disk);
-
-	clear_bit(GD_NEED_PART_SCAN, &disk->state);
-
-	/*
-	 * Historically we only set the capacity to zero for devices that
-	 * support partitions (independ of actually having partitions created).
-	 * Doing that is rather inconsistent, but changing it broke legacy
-	 * udisks polling for legacy ide-cdrom devices.  Use the crude check
-	 * below to get the sane behavior for most device while not breaking
-	 * userspace for this particular setup.
-	 */
-	if (invalidate) {
-		if (disk_part_scan_enabled(disk) ||
-		    !(disk->flags & GENHD_FL_REMOVABLE))
-			set_capacity(disk, 0);
-	}
-
-	if (get_capacity(disk)) {
-		ret = blk_add_partitions(disk, bdev);
-		if (ret == -EAGAIN)
-			goto rescan;
-	} else if (invalidate) {
-		/*
-		 * Tell userspace that the media / partition table may have
-		 * changed.
-		 */
-		kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
-	}
-
-	return ret;
-}
-/*
- * Only exported for loop and dasd for historic reasons.  Don't use in new
- * code!
- */
-EXPORT_SYMBOL_GPL(bdev_disk_changed);
-
 static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
 {
 	struct gendisk *disk = bdev->bd_disk;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 03d684f0498f..f5f0c9bdf1d2 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -257,7 +257,6 @@ static inline sector_t get_capacity(struct gendisk *disk)
 }
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
-int blk_add_partitions(struct gendisk *disk, struct block_device *bdev);
 void blk_drop_partitions(struct gendisk *disk);
 
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
-- 
2.30.2

[PATCH 2/2] block: pass a gendisk to bdev_disk_changed

[Christoph Hellwig]

bdev_disk_changed can only operate on whole devices.  Make that clear
by passing a gendisk instead of the struct block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/partitions/core.c         | 22 ++++++++++------------
 drivers/block/loop.c            | 21 ++++++++++-----------
 drivers/s390/block/dasd_genhd.c |  4 ++--
 fs/block_dev.c                  |  4 ++--
 include/linux/genhd.h           |  2 +-
 5 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index b79785f7027c..347c56a51d87 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -120,8 +120,7 @@ static void free_partitions(struct parsed_partitions *state)
 	kfree(state);
 }
 
-static struct parsed_partitions *check_partition(struct gendisk *hd,
-		struct block_device *bdev)
+static struct parsed_partitions *check_partition(struct gendisk *hd)
 {
 	struct parsed_partitions *state;
 	int i, res, err;
@@ -136,7 +135,7 @@ static struct parsed_partitions *check_partition(struct gendisk *hd,
 	}
 	state->pp_buf[0] = '\0';
 
-	state->bdev = bdev;
+	state->bdev = hd->part0;
 	disk_name(hd, 0, state->name);
 	snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
 	if (isdigit(state->name[strlen(state->name)-1]))
@@ -546,7 +545,7 @@ void blk_drop_partitions(struct gendisk *disk)
 	}
 }
 
-static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
+static bool blk_add_partition(struct gendisk *disk,
 		struct parsed_partitions *state, int p)
 {
 	sector_t size = state->parts[p].size;
@@ -596,7 +595,7 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 	return true;
 }
 
-static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
+static int blk_add_partitions(struct gendisk *disk)
 {
 	struct parsed_partitions *state;
 	int ret = -EAGAIN, p;
@@ -604,7 +603,7 @@ static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 	if (!disk_part_scan_enabled(disk))
 		return 0;
 
-	state = check_partition(disk, bdev);
+	state = check_partition(disk);
 	if (!state)
 		return 0;
 	if (IS_ERR(state)) {
@@ -648,7 +647,7 @@ static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 
 	for (p = 1; p < state->limit; p++)
-		if (!blk_add_partition(disk, bdev, state, p))
+		if (!blk_add_partition(disk, state, p))
 			goto out_free_state;
 
 	ret = 0;
@@ -657,9 +656,8 @@ static int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
 	return ret;
 }
 
-int bdev_disk_changed(struct block_device *bdev, bool invalidate)
+int bdev_disk_changed(struct gendisk *disk, bool invalidate)
 {
-	struct gendisk *disk = bdev->bd_disk;
 	int ret = 0;
 
 	lockdep_assert_held(&disk->open_mutex);
@@ -670,8 +668,8 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 rescan:
 	if (disk->open_partitions)
 		return -EBUSY;
-	sync_blockdev(bdev);
-	invalidate_bdev(bdev);
+	sync_blockdev(disk->part0);
+	invalidate_bdev(disk->part0);
 	blk_drop_partitions(disk);
 
 	clear_bit(GD_NEED_PART_SCAN, &disk->state);
@@ -691,7 +689,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	}
 
 	if (get_capacity(disk)) {
-		ret = blk_add_partitions(disk, bdev);
+		ret = blk_add_partitions(disk);
 		if (ret == -EAGAIN)
 			goto rescan;
 	} else if (invalidate) {
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 40b7c6c470f2..c6e73c051790 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -647,14 +647,13 @@ static inline void loop_update_dio(struct loop_device *lo)
 				lo->use_dio);
 }
 
-static void loop_reread_partitions(struct loop_device *lo,
-				   struct block_device *bdev)
+static void loop_reread_partitions(struct loop_device *lo)
 {
 	int rc;
 
-	mutex_lock(&bdev->bd_disk->open_mutex);
-	rc = bdev_disk_changed(bdev, false);
-	mutex_unlock(&bdev->bd_disk->open_mutex);
+	mutex_lock(&lo->lo_disk->open_mutex);
+	rc = bdev_disk_changed(lo->lo_disk, false);
+	mutex_unlock(&lo->lo_disk->open_mutex);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -752,7 +751,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	 */
 	fput(old_file);
 	if (partscan)
-		loop_reread_partitions(lo, bdev);
+		loop_reread_partitions(lo);
 	return 0;
 
 out_err:
@@ -1175,7 +1174,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	bdgrab(bdev);
 	mutex_unlock(&lo->lo_mutex);
 	if (partscan)
-		loop_reread_partitions(lo, bdev);
+		loop_reread_partitions(lo);
 	if (!(mode & FMODE_EXCL))
 		bd_abort_claiming(bdev, loop_configure);
 	return 0;
@@ -1269,10 +1268,10 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 		 * current holder is released.
 		 */
 		if (!release)
-			mutex_lock(&bdev->bd_disk->open_mutex);
-		err = bdev_disk_changed(bdev, false);
+			mutex_lock(&lo->lo_disk->open_mutex);
+		err = bdev_disk_changed(lo->lo_disk, false);
 		if (!release)
-			mutex_unlock(&bdev->bd_disk->open_mutex);
+			mutex_unlock(&lo->lo_disk->open_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);
@@ -1417,7 +1416,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 out_unlock:
 	mutex_unlock(&lo->lo_mutex);
 	if (partscan)
-		loop_reread_partitions(lo, bdev);
+		loop_reread_partitions(lo);
 
 	return err;
 }
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index bf2082d461c7..493e8469893c 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -110,7 +110,7 @@ int dasd_scan_partitions(struct dasd_block *block)
 	}
 
 	mutex_lock(&block->gdp->open_mutex);
-	rc = bdev_disk_changed(bdev, false);
+	rc = bdev_disk_changed(block->gdp, false);
 	mutex_unlock(&block->gdp->open_mutex);
 	if (rc)
 		DBF_DEV_EVENT(DBF_ERR, block->base,
@@ -146,7 +146,7 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	block->bdev = NULL;
 
 	mutex_lock(&bdev->bd_disk->open_mutex);
-	bdev_disk_changed(bdev, true);
+	bdev_disk_changed(bdev->bd_disk, true);
 	mutex_unlock(&bdev->bd_disk->open_mutex);
 
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 5b3a73ecb696..34253d155f5c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1253,7 +1253,7 @@ static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
 			/* avoid ghost partitions on a removed medium */
 			if (ret == -ENOMEDIUM &&
 			     test_bit(GD_NEED_PART_SCAN, &disk->state))
-				bdev_disk_changed(bdev, true);
+				bdev_disk_changed(disk, true);
 			return ret;
 		}
 	}
@@ -1264,7 +1264,7 @@ static int blkdev_get_whole(struct block_device *bdev, fmode_t mode)
 			bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
 	}
 	if (test_bit(GD_NEED_PART_SCAN, &disk->state))
-		bdev_disk_changed(bdev, false);
+		bdev_disk_changed(disk, false);
 	bdev->bd_openers++;
 	return 0;;
 }
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index f5f0c9bdf1d2..13b34177cc85 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -256,7 +256,7 @@ static inline sector_t get_capacity(struct gendisk *disk)
 	return bdev_nr_sectors(disk->part0);
 }
 
-int bdev_disk_changed(struct block_device *bdev, bool invalidate);
+int bdev_disk_changed(struct gendisk *disk, bool invalidate);
 void blk_drop_partitions(struct gendisk *disk);
 
 extern struct gendisk *__alloc_disk_node(int minors, int node_id);
-- 
2.30.2

Re: minor cleanups to bdev_disk_changed

[Jens Axboe]

On 6/24/21 6:32 AM, Christoph Hellwig wrote:
> Hi Jens,
> 
> two patches to clean up bdev_disk_changed that got lost large merge
> window to avoid merge conflicts.

Applied, thanks.

-- 
Jens Axboe