Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Jan Kara <jack@suse.cz>
Cc: linux-block@vger.kernel.org, linux-s390@vger.kernel.org,
	Stefan Haberland <sth@linux.ibm.com>
Subject: [PATCH 5/7] block: remove (__)blkdev_reread_part as an exported API
Date: Thu, 14 Nov 2019 15:34:36 +0100
Message-ID: <20191114143438.14681-6-hch@lst.de> (raw)
In-Reply-To: <20191114143438.14681-1-hch@lst.de>

In general drivers should never mess with partition tables directly.
Unfortunately s390 and loop do for somewhat historic reasons, but they
can use bdev_disk_changed directly instead when we export it as they
satisfy the sanity checks we have in __blkdev_reread_part.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>	[dasd]
Reviewed-by: Jan Kara <jack@suse.cz>
---
 block/ioctl.c                   | 35 +++++----------------------------
 drivers/block/loop.c            | 13 +++++++-----
 drivers/s390/block/dasd_genhd.c |  4 +++-
 fs/block_dev.c                  |  7 +++++++
 include/linux/fs.h              |  2 --
 5 files changed, 23 insertions(+), 38 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 5ccd9f016594..7ac8a66c9787 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -155,46 +155,21 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 	}
 }
 
-/*
- * This is an exported API for the block driver, and will not
- * acquire bd_mutex. This API should be used in case that
- * caller has held bd_mutex already.
- */
-int __blkdev_reread_part(struct block_device *bdev)
+static int blkdev_reread_part(struct block_device *bdev)
 {
+	int ret;
+
 	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev != bdev->bd_contains)
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
 
-	lockdep_assert_held(&bdev->bd_mutex);
-
-	return bdev_disk_changed(bdev, false);
-}
-EXPORT_SYMBOL(__blkdev_reread_part);
-
-/*
- * This is an exported API for the block driver, and will
- * try to acquire bd_mutex. If bd_mutex has been held already
- * in current context, please call __blkdev_reread_part().
- *
- * Make sure the held locks in current context aren't required
- * in open()/close() handler and I/O path for avoiding ABBA deadlock:
- * - bd_mutex is held before calling block driver's open/close
- *   handler
- * - reading partition table may submit I/O to the block device
- */
-int blkdev_reread_part(struct block_device *bdev)
-{
-	int res;
-
 	mutex_lock(&bdev->bd_mutex);
-	res = __blkdev_reread_part(bdev);
+	ret = bdev_disk_changed(bdev, false);
 	mutex_unlock(&bdev->bd_mutex);
 
-	return res;
+	return ret;
 }
-EXPORT_SYMBOL(blkdev_reread_part);
 
 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 		unsigned long arg, unsigned long flags)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index ef6e251857c8..739b372a5112 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -640,7 +640,9 @@ static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	rc = blkdev_reread_part(bdev);
+	mutex_lock(&bdev->bd_mutex);
+	rc = bdev_disk_changed(bdev, false);
+	mutex_unlock(&bdev->bd_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);
@@ -1164,10 +1166,11 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
 		 * must be at least one and it can only become zero when the
 		 * current holder is released.
 		 */
-		if (release)
-			err = __blkdev_reread_part(bdev);
-		else
-			err = blkdev_reread_part(bdev);
+		if (!release)
+			mutex_lock(&bdev->bd_mutex);
+		err = bdev_disk_changed(bdev, false);
+		if (!release)
+			mutex_unlock(&bdev->bd_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 5542d9eadfe0..7d079154f849 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -116,7 +116,9 @@ int dasd_scan_partitions(struct dasd_block *block)
 		return -ENODEV;
 	}
 
-	rc = blkdev_reread_part(bdev);
+	mutex_lock(&bdev->bd_mutex);
+	rc = bdev_disk_changed(bdev, false);
+	mutex_unlock(&bdev->bd_mutex);
 	if (rc)
 		DBF_DEV_EVENT(DBF_ERR, block->base,
 				"scan partitions error, rc %d", rc);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index ae16466a67f7..9558a2f064b1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1513,6 +1513,8 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	struct gendisk *disk = bdev->bd_disk;
 	int ret;
 
+	lockdep_assert_held(&bdev->bd_mutex);
+
 rescan:
 	ret = blk_drop_partitions(disk, bdev);
 	if (ret)
@@ -1540,6 +1542,11 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	return ret;
 }
+/*
+ * Only exported for for loop and dasd for historic reasons.  Don't use in new
+ * code!
+ */
+EXPORT_SYMBOL_GPL(bdev_disk_changed);
 
 /*
  * bd_mutex locking:
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d233dd661df7..ae6c5c37f3ae 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2632,8 +2632,6 @@ extern void bd_finish_claiming(struct block_device *bdev,
 extern void bd_abort_claiming(struct block_device *bdev,
 			      struct block_device *whole, void *holder);
 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
-extern int __blkdev_reread_part(struct block_device *bdev);
-extern int blkdev_reread_part(struct block_device *bdev);
 
 #ifdef CONFIG_SYSFS
 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
-- 
2.20.1


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-14 14:34 disk revalidation cleanups and fixlets v2 Christoph Hellwig
2019-11-14 14:34 ` [PATCH 1/7] block: refactor rescan_partitions Christoph Hellwig
2019-11-14 14:34 ` [PATCH 2/7] block: merge invalidate_partitions into rescan_partitions Christoph Hellwig
2019-11-15 10:05   ` Hannes Reinecke
2019-11-30 21:49   ` Eric Biggers
2019-11-30 22:06     ` Eric Biggers
2019-12-02  7:21       ` Christoph Hellwig
2019-11-14 14:34 ` [PATCH 3/7] block: move rescan_partitions to fs/block_dev.c Christoph Hellwig
2019-11-15 10:06   ` Hannes Reinecke
2019-11-14 14:34 ` [PATCH 4/7] block: fix bdev_disk_changed for non-partitioned devices Christoph Hellwig
2019-11-15 10:07   ` Hannes Reinecke
2019-11-14 14:34 ` Christoph Hellwig [this message]
2019-11-15 10:08   ` [PATCH 5/7] block: remove (__)blkdev_reread_part as an exported API Hannes Reinecke
2019-11-14 14:34 ` [PATCH 6/7] block: move clearing bd_invalidated into check_disk_size_change Christoph Hellwig
2019-11-15 10:08   ` Hannes Reinecke
2019-11-14 14:34 ` [PATCH 7/7] block: move setting bd_invalidated from flush_disk to check_disk_change Christoph Hellwig
2019-11-15 10:09   ` Hannes Reinecke
2019-11-14 14:44 ` disk revalidation cleanups and fixlets v2 Jens Axboe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191114143438.14681-6-hch@lst.de \
    --to=hch@lst.de \
    --cc=axboe@kernel.dk \
    --cc=jack@suse.cz \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=sth@linux.ibm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org
	public-inbox-index linux-block

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git