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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: "Justin Sanders" <justin@coraid.com>,
	"Josef Bacik" <josef@toxicpanda.com>,
	"Ilya Dryomov" <idryomov@gmail.com>,
	"Jack Wang" <jinpu.wang@cloud.ionos.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>,
	"Minchan Kim" <minchan@kernel.org>,
	"Mike Snitzer" <snitzer@redhat.com>, "Song Liu" <song@kernel.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	dm-devel@redhat.com, linux-block@vger.kernel.org,
	drbd-dev@lists.linbit.com, nbd@other.debian.org,
	ceph-devel@vger.kernel.org, xen-devel@lists.xenproject.org,
	linux-raid@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 60/78] zram: remove the claim mechanism
Date: Mon, 16 Nov 2020 15:57:51 +0100	[thread overview]
Message-ID: <20201116145809.410558-61-hch@lst.de> (raw)
In-Reply-To: <20201116145809.410558-1-hch@lst.de>

The zram claim mechanism was added to ensure no new opens come in
during teardown.  But the proper way to archive that is to call
del_gendisk first, which takes care of all that.  Once del_gendisk
is called in the right place, the reset side can also be simplified
as no I/O can be outstanding on a block device that is not open.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/zram/zram_drv.c | 76 ++++++++++-------------------------
 1 file changed, 21 insertions(+), 55 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 6d15d51cee2b7e..3641434a9b154d 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1756,64 +1756,33 @@ static ssize_t disksize_store(struct device *dev,
 static ssize_t reset_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
-	int ret;
-	unsigned short do_reset;
-	struct zram *zram;
+	struct zram *zram = dev_to_zram(dev);
 	struct block_device *bdev;
+	unsigned short do_reset;
+	int ret = 0;
 
 	ret = kstrtou16(buf, 10, &do_reset);
 	if (ret)
 		return ret;
-
 	if (!do_reset)
 		return -EINVAL;
 
-	zram = dev_to_zram(dev);
 	bdev = bdget_disk(zram->disk, 0);
 	if (!bdev)
 		return -ENOMEM;
 
 	mutex_lock(&bdev->bd_mutex);
-	/* Do not reset an active device or claimed device */
-	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
-		bdput(bdev);
-		return -EBUSY;
-	}
-
-	/* From now on, anyone can't open /dev/zram[0-9] */
-	zram->claim = true;
+	if (bdev->bd_openers)
+		ret = -EBUSY;
+	else
+		zram_reset_device(zram);
 	mutex_unlock(&bdev->bd_mutex);
-
-	/* Make sure all the pending I/O are finished */
-	fsync_bdev(bdev);
-	zram_reset_device(zram);
 	bdput(bdev);
 
-	mutex_lock(&bdev->bd_mutex);
-	zram->claim = false;
-	mutex_unlock(&bdev->bd_mutex);
-
-	return len;
-}
-
-static int zram_open(struct block_device *bdev, fmode_t mode)
-{
-	int ret = 0;
-	struct zram *zram;
-
-	WARN_ON(!mutex_is_locked(&bdev->bd_mutex));
-
-	zram = bdev->bd_disk->private_data;
-	/* zram was claimed to reset so open request fails */
-	if (zram->claim)
-		ret = -EBUSY;
-
-	return ret;
+	return ret ? ret : len;
 }
 
 static const struct block_device_operations zram_devops = {
-	.open = zram_open,
 	.submit_bio = zram_submit_bio,
 	.swap_slot_free_notify = zram_slot_free_notify,
 	.rw_page = zram_rw_page,
@@ -1821,7 +1790,6 @@ static const struct block_device_operations zram_devops = {
 };
 
 static const struct block_device_operations zram_wb_devops = {
-	.open = zram_open,
 	.submit_bio = zram_submit_bio,
 	.swap_slot_free_notify = zram_slot_free_notify,
 	.owner = THIS_MODULE
@@ -1972,34 +1940,32 @@ static int zram_add(void)
 	return ret;
 }
 
-static int zram_remove(struct zram *zram)
+static bool zram_busy(struct zram *zram)
 {
 	struct block_device *bdev;
+	bool busy = false;
 
 	bdev = bdget_disk(zram->disk, 0);
-	if (!bdev)
-		return -ENOMEM;
-
-	mutex_lock(&bdev->bd_mutex);
-	if (bdev->bd_openers || zram->claim) {
-		mutex_unlock(&bdev->bd_mutex);
+	if (bdev) {
+		if (bdev->bd_openers)
+			busy = true;
 		bdput(bdev);
-		return -EBUSY;
 	}
 
-	zram->claim = true;
-	mutex_unlock(&bdev->bd_mutex);
+	return busy;
+}
 
-	zram_debugfs_unregister(zram);
+static int zram_remove(struct zram *zram)
+{
+	if (zram_busy(zram))
+		return -EBUSY;
 
-	/* Make sure all the pending I/O are finished */
-	fsync_bdev(bdev);
+	del_gendisk(zram->disk);
+	zram_debugfs_unregister(zram);
 	zram_reset_device(zram);
-	bdput(bdev);
 
 	pr_info("Removed device: %s\n", zram->disk->disk_name);
 
-	del_gendisk(zram->disk);
 	blk_cleanup_queue(zram->disk->queue);
 	put_disk(zram->disk);
 	kfree(zram);
-- 
2.29.2


  parent reply	other threads:[~2020-11-16 15:01 UTC|newest]

Thread overview: 113+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16 14:56 cleanup updating the size of block devices v3 Christoph Hellwig
2020-11-16 14:56 ` [PATCH 01/78] block: remove the call to __invalidate_device in check_disk_size_change Christoph Hellwig
2020-11-16 14:56 ` [PATCH 02/78] loop: let set_capacity_revalidate_and_notify update the bdev size Christoph Hellwig
2020-11-16 14:56 ` [PATCH 03/78] nvme: " Christoph Hellwig
2020-11-16 14:56 ` [PATCH 04/78] sd: update the bdev size in sd_revalidate_disk Christoph Hellwig
2020-11-16 14:56 ` [PATCH 05/78] block: remove the update_bdev parameter to set_capacity_revalidate_and_notify Christoph Hellwig
2020-11-16 14:56 ` [PATCH 06/78] nbd: remove the call to set_blocksize Christoph Hellwig
2020-11-16 14:56 ` [PATCH 07/78] nbd: move the task_recv check into nbd_size_update Christoph Hellwig
2020-11-16 14:56 ` [PATCH 08/78] nbd: refactor size updates Christoph Hellwig
2020-11-16 14:57 ` [PATCH 09/78] nbd: validate the block size in nbd_set_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 10/78] nbd: use set_capacity_and_notify Christoph Hellwig
2020-11-16 14:57 ` [PATCH 11/78] aoe: don't call set_capacity from irq context Christoph Hellwig
2020-11-16 14:57 ` [PATCH 12/78] dm: use set_capacity_and_notify Christoph Hellwig
2021-02-12 15:45   ` Mike Snitzer
2021-02-16 11:46     ` Christoph Hellwig
2020-11-16 14:57 ` [PATCH 13/78] pktcdvd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 14/78] nvme: use set_capacity_and_notify in nvme_set_queue_dying Christoph Hellwig
2020-11-16 14:57 ` [PATCH 15/78] drbd: use set_capacity_and_notify Christoph Hellwig
2020-11-16 14:57 ` [PATCH 16/78] rbd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 17/78] rnbd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 18/78] zram: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 19/78] dm-raid: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 20/78] md: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 21/78] md: remove a spurious call to revalidate_disk_size in update_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 22/78] virtio-blk: remove a spurious call to revalidate_disk_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 23/78] block: unexport revalidate_disk_size Christoph Hellwig
2020-11-16 14:57 ` [PATCH 24/78] mtd_blkdevs: don't override BLKFLSBUF Christoph Hellwig
2020-11-16 14:57 ` [PATCH 25/78] block: don't call into the driver for BLKFLSBUF Christoph Hellwig
2020-11-16 14:57 ` [PATCH 26/78] block: add a new set_read_only method Christoph Hellwig
2020-11-16 14:57 ` [PATCH 27/78] rbd: implement ->set_read_only to hook into BLKROSET processing Christoph Hellwig
2020-11-16 14:57 ` [PATCH 28/78] md: " Christoph Hellwig
2020-11-16 17:37   ` Song Liu
2020-11-16 14:57 ` [PATCH 29/78] dasd: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 30/78] block: don't call into the driver for BLKROSET Christoph Hellwig
2020-11-20  7:19   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 31/78] loop: use set_disk_ro Christoph Hellwig
2020-11-20  7:20   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 32/78] block: remove set_device_ro Christoph Hellwig
2020-11-20  7:20   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 33/78] block: remove __blkdev_driver_ioctl Christoph Hellwig
2020-11-20  7:22   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 34/78] block: propagate BLKROSET to all partitions Christoph Hellwig
2020-11-20  7:23   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 35/78] block: cleanup del_gendisk a bit Christoph Hellwig
2020-11-16 14:57 ` [PATCH 36/78] block: open code kobj_map into in block/genhd.c Christoph Hellwig
2020-11-16 14:57 ` [PATCH 37/78] block: split block_class_lock Christoph Hellwig
2020-11-16 14:57 ` [PATCH 38/78] block: rework requesting modules for unclaimed devices Christoph Hellwig
2020-11-16 14:57 ` [PATCH 39/78] block: add an optional probe callback to major_names Christoph Hellwig
2020-11-16 14:57 ` [PATCH 40/78] ide: remove ide_{,un}register_region Christoph Hellwig
2020-11-16 14:57 ` [PATCH 41/78] swim: don't call blk_register_region Christoph Hellwig
2020-11-16 14:57 ` [PATCH 42/78] sd: use __register_blkdev to avoid a modprobe for an unregistered dev_t Christoph Hellwig
2020-11-16 14:57 ` [PATCH 43/78] brd: use __register_blkdev to allocate devices on demand Christoph Hellwig
2020-11-16 14:57 ` [PATCH 44/78] loop: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 45/78] md: " Christoph Hellwig
2020-11-16 14:57 ` [PATCH 46/78] ide: switch to __register_blkdev for command set probing Christoph Hellwig
2020-11-16 14:57 ` [PATCH 47/78] floppy: use a separate gendisk for each media format Christoph Hellwig
2020-11-16 14:57 ` [PATCH 48/78] amiflop: use separate gendisks for Amiga vs MS-DOS mode Christoph Hellwig
2020-11-16 14:57 ` [PATCH 49/78] ataflop: use a separate gendisk for each media format Christoph Hellwig
2020-11-16 14:57 ` [PATCH 50/78] z2ram: reindent Christoph Hellwig
2020-11-16 14:57 ` [PATCH 51/78] z2ram: use separate gendisk for the different modes Christoph Hellwig
2020-11-16 14:57 ` [PATCH 52/78] block: switch gendisk lookup to a simple xarray Christoph Hellwig
2020-11-16 14:57 ` [PATCH 53/78] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
2020-11-20  7:25   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 54/78] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
2020-11-20  7:25   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 55/78] block: change the hash used for looking up block devices Christoph Hellwig
2020-11-20  7:26   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 56/78] init: refactor name_to_dev_t Christoph Hellwig
2020-11-20  7:31   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 57/78] init: refactor devt_from_partuuid Christoph Hellwig
2020-11-20  7:33   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 58/78] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
2020-11-20  7:34   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 59/78] mtip32xx: remove the call to fsync_bdev on removal Christoph Hellwig
2020-11-20  7:35   ` Hannes Reinecke
2020-11-16 14:57 ` Christoph Hellwig [this message]
2020-11-20  7:37   ` [PATCH 60/78] zram: remove the claim mechanism Hannes Reinecke
2020-11-26  1:11   ` Minchan Kim
2020-11-26  9:59     ` Christoph Hellwig
2020-11-16 14:57 ` [PATCH 61/78] zram: do not call set_blocksize Christoph Hellwig
2020-11-20  7:38   ` Hannes Reinecke
2020-11-26  1:16   ` Minchan Kim
2020-11-16 14:57 ` [PATCH 62/78] loop: " Christoph Hellwig
2020-11-20  7:38   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 63/78] bcache: remove a superflous lookup_bdev all Christoph Hellwig
2020-11-16 14:57 ` [PATCH 64/78] dm: simplify flush_bio initialization in __send_empty_flush Christoph Hellwig
2020-11-20  7:41   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 65/78] dm: remove the block_device reference in struct mapped_device Christoph Hellwig
2020-11-20  7:43   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 66/78] block: keep a block_device reference for each hd_struct Christoph Hellwig
2020-11-20  7:50   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 67/78] block: simplify the block device claiming interface Christoph Hellwig
2020-11-20  7:51   ` Hannes Reinecke
2020-11-16 14:57 ` [PATCH 68/78] block: remove ->bd_contains Christoph Hellwig
2020-11-20  7:52   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 69/78] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
2020-11-20  7:55   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 70/78] block: replace bd_mutex with a per-gendisk mutex Christoph Hellwig
2020-11-20  7:58   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 71/78] block: add a bdev_kobj helper Christoph Hellwig
2020-11-20  7:59   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 72/78] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
2020-11-20  7:59   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 73/78] block: use put_device in put_disk Christoph Hellwig
2020-11-20  8:02   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 74/78] block: merge struct block_device and struct hd_struct Christoph Hellwig
2020-11-20  8:58   ` Hannes Reinecke
2020-11-16 14:58 ` [PATCH 75/78] block: stop using bdget_disk for partition 0 Christoph Hellwig
2020-11-16 14:58 ` [PATCH 76/78] filemap: use ->f_mapping over ->i_mapping consistently Christoph Hellwig
2020-11-16 14:58 ` [PATCH 77/78] fs: simplify the get_super_thawed interface Christoph Hellwig
2020-11-16 14:58 ` [PATCH 78/78] block: remove i_bdev Christoph Hellwig
2020-11-16 15:05 ` cleanup updating the size of block devices v3 Christoph Hellwig
2020-11-16 15:40 ` Jens Axboe

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