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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Song Liu <song@kernel.org>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>,
	"Minchan Kim" <minchan@kernel.org>,
	"Nitin Gupta" <ngupta@vflare.org>,
	"Stefan Haberland" <sth@linux.ibm.com>,
	"Jan Hoeppner" <hoeppner@linux.ibm.com>,
	linux-block@vger.kernel.org, linux-raid@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: [PATCH 06/15] md: do not return existing mddevs from mddev_find_or_alloc
Date: Tue, 30 Mar 2021 18:17:18 +0200	[thread overview]
Message-ID: <20210330161727.2297292-7-hch@lst.de> (raw)
In-Reply-To: <20210330161727.2297292-1-hch@lst.de>

Instead of returning an existing mddev, just for it to be discarded
later directly return -EEXIST.  Rename the function to mddev_alloc now
that it doesn't find an existing mddev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/md.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index ea9c92c113619b..e614c40ca58974 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -782,26 +782,24 @@ static struct mddev *mddev_find(dev_t unit)
 	return mddev;
 }
 
-static struct mddev *mddev_find_or_alloc(dev_t unit)
+static struct mddev *mddev_alloc(dev_t unit)
 {
-	struct mddev *mddev = NULL, *new;
+	struct mddev *new;
+	int error;
 
 	if (unit && MAJOR(unit) != MD_MAJOR)
 		unit &= ~((1 << MdpMinorShift) - 1);
 
 	new = kzalloc(sizeof(*new), GFP_KERNEL);
 	if (!new)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	mddev_init(new);
 
 	spin_lock(&all_mddevs_lock);
 	if (unit) {
-		mddev = mddev_find_locked(unit);
-		if (mddev) {
-			mddev_get(mddev);
+		error = -EEXIST;
+		if (mddev_find_locked(unit))
 			goto out_free_new;
-		}
-
 		new->unit = unit;
 		if (MAJOR(unit) == MD_MAJOR)
 			new->md_minor = MINOR(unit);
@@ -809,6 +807,7 @@ static struct mddev *mddev_find_or_alloc(dev_t unit)
 			new->md_minor = MINOR(unit) >> MdpMinorShift;
 		new->hold_active = UNTIL_IOCTL;
 	} else {
+		error = -ENODEV;
 		new->unit = mddev_alloc_unit();
 		if (!new->unit)
 			goto out_free_new;
@@ -822,7 +821,7 @@ static struct mddev *mddev_find_or_alloc(dev_t unit)
 out_free_new:
 	spin_unlock(&all_mddevs_lock);
 	kfree(new);
-	return mddev;
+	return ERR_PTR(error);
 }
 
 static struct attribute_group md_redundancy_group;
@@ -5661,29 +5660,29 @@ static int md_alloc(dev_t dev, char *name)
 	 * writing to /sys/module/md_mod/parameters/new_array.
 	 */
 	static DEFINE_MUTEX(disks_mutex);
-	struct mddev *mddev = mddev_find_or_alloc(dev);
+	struct mddev *mddev;
 	struct gendisk *disk;
 	int partitioned;
 	int shift;
 	int unit;
-	int error;
+	int error ;
 
-	if (!mddev)
-		return -ENODEV;
-
-	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
-	shift = partitioned ? MdpMinorShift : 0;
-	unit = MINOR(mddev->unit) >> shift;
-
-	/* wait for any previous instance of this device to be
-	 * completely removed (mddev_delayed_delete).
+	/*
+	 * Wait for any previous instance of this device to be completely
+	 * removed (mddev_delayed_delete).
 	 */
 	flush_workqueue(md_misc_wq);
 
 	mutex_lock(&disks_mutex);
-	error = -EEXIST;
-	if (mddev->gendisk)
-		goto abort;
+	mddev = mddev_alloc(dev);
+	if (IS_ERR(mddev)) {
+		mutex_unlock(&disks_mutex);
+		return PTR_ERR(mddev);
+	}
+
+	partitioned = (MAJOR(mddev->unit) != MD_MAJOR);
+	shift = partitioned ? MdpMinorShift : 0;
+	unit = MINOR(mddev->unit) >> shift;
 
 	if (name && !dev) {
 		/* Need to ensure that 'name' is not a duplicate.
@@ -5695,6 +5694,7 @@ static int md_alloc(dev_t dev, char *name)
 			if (mddev2->gendisk &&
 			    strcmp(mddev2->gendisk->disk_name, name) == 0) {
 				spin_unlock(&all_mddevs_lock);
+				error = -EEXIST;
 				goto abort;
 			}
 		spin_unlock(&all_mddevs_lock);
-- 
2.30.1


  parent reply	other threads:[~2021-03-30 16:18 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-30 16:17 move bd_mutex to the gendisk Christoph Hellwig
2021-03-30 16:17 ` [PATCH 01/15] md: remove the code to flush an old instance in md_open Christoph Hellwig
2021-03-31  3:29   ` heming.zhao
2021-03-31  6:53     ` Christoph Hellwig
2021-03-30 16:17 ` [PATCH 02/15] md: factor out a mddev_find_locked helper from mddev_find Christoph Hellwig
2021-03-30 16:17 ` [PATCH 03/15] md: factor out a mddev_alloc_unit " Christoph Hellwig
2021-03-30 16:17 ` [PATCH 04/15] md: split mddev_find Christoph Hellwig
2021-03-30 16:17 ` [PATCH 05/15] md: refactor mddev_find_or_alloc Christoph Hellwig
2021-03-30 16:17 ` Christoph Hellwig [this message]
2021-03-30 16:17 ` [PATCH 07/15] block: remove the -ERESTARTSYS handling in blkdev_get_by_dev Christoph Hellwig
2021-03-30 16:17 ` [PATCH 08/15] block: split __blkdev_get Christoph Hellwig
2021-03-30 16:17 ` [PATCH 09/15] block: move sync_blockdev from __blkdev_put to blkdev_put Christoph Hellwig
2021-03-30 16:17 ` [PATCH 10/15] block: move bd_mutex to struct gendisk Christoph Hellwig
2021-04-01  8:25   ` Roger Pau Monné
2021-04-08 14:29   ` Stefan Haberland
2021-03-30 16:17 ` [PATCH 11/15] block: move adjusting bd_part_count out of __blkdev_get Christoph Hellwig
2021-03-30 16:17 ` [PATCH 12/15] block: split __blkdev_put Christoph Hellwig
2021-03-30 16:17 ` [PATCH 13/15] block: move bd_part_count to struct gendisk Christoph Hellwig
2021-03-30 16:17 ` [PATCH 14/15] block: factor out a part_devt helper Christoph Hellwig
2021-03-30 16:17 ` [PATCH 15/15] block: remove bdget_disk Christoph Hellwig
2021-03-30 23:37   ` Chaitanya Kulkarni

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