From: Jan Kara <jack@suse.cz>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, Tejun Heo <tj@kernel.org>,
Josef Bacik <josef@toxicpanda.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Coly Li <colyli@suse.de>, Mike Snitzer <snitzer@redhat.com>,
dm-devel@redhat.com, Richard Weinberger <richard@nod.at>,
Jan Kara <jack@suse.com>,
linux-block@vger.kernel.org, xen-devel@lists.xenproject.org,
linux-bcache@vger.kernel.org, linux-mtd@lists.infradead.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 12/20] block: simplify the block device claiming interface
Date: Thu, 19 Nov 2020 11:07:30 +0100 [thread overview]
Message-ID: <20201119100730.GU1981@quack2.suse.cz> (raw)
In-Reply-To: <20201118084800.2339180-13-hch@lst.de>
On Wed 18-11-20 09:47:52, Christoph Hellwig wrote:
> Stop passing the whole device as a separate argument given that it
> can be trivially deducted.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> drivers/block/loop.c | 12 +++-----
> fs/block_dev.c | 69 +++++++++++++++++++-----------------------
> include/linux/blkdev.h | 6 ++--
> 3 files changed, 38 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index b42c728620c9e4..599e94a7e69259 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1071,7 +1071,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
> struct file *file;
> struct inode *inode;
> struct address_space *mapping;
> - struct block_device *claimed_bdev = NULL;
> int error;
> loff_t size;
> bool partscan;
> @@ -1090,8 +1089,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
> * here to avoid changing device under exclusive owner.
> */
> if (!(mode & FMODE_EXCL)) {
> - claimed_bdev = bdev->bd_contains;
> - error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
> + error = bd_prepare_to_claim(bdev, loop_configure);
> if (error)
> goto out_putf;
> }
> @@ -1178,15 +1176,15 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
> mutex_unlock(&loop_ctl_mutex);
> if (partscan)
> loop_reread_partitions(lo, bdev);
> - if (claimed_bdev)
> - bd_abort_claiming(bdev, claimed_bdev, loop_configure);
> + if (!(mode & FMODE_EXCL))
> + bd_abort_claiming(bdev, loop_configure);
> return 0;
>
> out_unlock:
> mutex_unlock(&loop_ctl_mutex);
> out_bdev:
> - if (claimed_bdev)
> - bd_abort_claiming(bdev, claimed_bdev, loop_configure);
> + if (!(mode & FMODE_EXCL))
> + bd_abort_claiming(bdev, loop_configure);
> out_putf:
> fput(file);
> out:
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index e94633dc6ad93b..dd52dbd266cde7 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -110,24 +110,20 @@ EXPORT_SYMBOL(invalidate_bdev);
> int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
> loff_t lstart, loff_t lend)
> {
> - struct block_device *claimed_bdev = NULL;
> - int err;
> -
> /*
> * If we don't hold exclusive handle for the device, upgrade to it
> * while we discard the buffer cache to avoid discarding buffers
> * under live filesystem.
> */
> if (!(mode & FMODE_EXCL)) {
> - claimed_bdev = bdev->bd_contains;
> - err = bd_prepare_to_claim(bdev, claimed_bdev,
> - truncate_bdev_range);
> + int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
> if (err)
> return err;
> }
> +
> truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
> - if (claimed_bdev)
> - bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range);
> + if (!(mode & FMODE_EXCL))
> + bd_abort_claiming(bdev, truncate_bdev_range);
> return 0;
> }
> EXPORT_SYMBOL(truncate_bdev_range);
> @@ -1047,7 +1043,6 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
> /**
> * bd_prepare_to_claim - claim a block device
> * @bdev: block device of interest
> - * @whole: the whole device containing @bdev, may equal @bdev
> * @holder: holder trying to claim @bdev
> *
> * Claim @bdev. This function fails if @bdev is already claimed by another
> @@ -1057,9 +1052,10 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
> * RETURNS:
> * 0 if @bdev can be claimed, -EBUSY otherwise.
> */
> -int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
> - void *holder)
> +int bd_prepare_to_claim(struct block_device *bdev, void *holder)
> {
> + struct block_device *whole = bdev->bd_contains;
> +
> retry:
> spin_lock(&bdev_lock);
> /* if someone else claimed, fail */
> @@ -1099,15 +1095,15 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
> /**
> * bd_finish_claiming - finish claiming of a block device
> * @bdev: block device of interest
> - * @whole: whole block device
> * @holder: holder that has claimed @bdev
> *
> * Finish exclusive open of a block device. Mark the device as exlusively
> * open by the holder and wake up all waiters for exclusive open to finish.
> */
> -static void bd_finish_claiming(struct block_device *bdev,
> - struct block_device *whole, void *holder)
> +static void bd_finish_claiming(struct block_device *bdev, void *holder)
> {
> + struct block_device *whole = bdev->bd_contains;
> +
> spin_lock(&bdev_lock);
> BUG_ON(!bd_may_claim(bdev, whole, holder));
> /*
> @@ -1132,11 +1128,10 @@ static void bd_finish_claiming(struct block_device *bdev,
> * also used when exclusive open is not actually desired and we just needed
> * to block other exclusive openers for a while.
> */
> -void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
> - void *holder)
> +void bd_abort_claiming(struct block_device *bdev, void *holder)
> {
> spin_lock(&bdev_lock);
> - bd_clear_claiming(whole, holder);
> + bd_clear_claiming(bdev->bd_contains, holder);
> spin_unlock(&bdev_lock);
> }
> EXPORT_SYMBOL(bd_abort_claiming);
> @@ -1434,7 +1429,7 @@ static void put_disk_and_module(struct gendisk *disk)
> static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
> int for_part)
> {
> - struct block_device *whole = NULL, *claiming = NULL;
> + struct block_device *whole = NULL;
> struct gendisk *disk = bdev->bd_disk;
> int ret;
> bool first_open = false, unblock_events = true, need_restart;
> @@ -1462,11 +1457,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>
> if (!for_part && (mode & FMODE_EXCL)) {
> WARN_ON_ONCE(!holder);
> - if (whole)
> - claiming = whole;
> - else
> - claiming = bdev;
> - ret = bd_prepare_to_claim(bdev, claiming, holder);
> + ret = bd_prepare_to_claim(bdev, holder);
> if (ret)
> goto out_put_whole;
> }
> @@ -1543,21 +1534,23 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
> }
> }
> bdev->bd_openers++;
> - if (for_part)
> + if (for_part) {
> bdev->bd_part_count++;
> - if (claiming)
> - bd_finish_claiming(bdev, claiming, holder);
> + } else if (mode & FMODE_EXCL) {
> + bd_finish_claiming(bdev, holder);
>
> - /*
> - * Block event polling for write claims if requested. Any write holder
> - * makes the write_holder state stick until all are released. This is
> - * good enough and tracking individual writeable reference is too
> - * fragile given the way @mode is used in blkdev_get/put().
> - */
> - if (claiming && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
> - (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
> - bdev->bd_write_holder = true;
> - unblock_events = false;
> + /*
> + * Block event polling for write claims if requested. Any write
> + * holder makes the write_holder state stick until all are
> + * released. This is good enough and tracking individual
> + * writeable reference is too fragile given the way @mode is
> + * used in blkdev_get/put().
> + */
> + if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
> + (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
> + bdev->bd_write_holder = true;
> + unblock_events = false;
> + }
> }
> mutex_unlock(&bdev->bd_mutex);
>
> @@ -1578,8 +1571,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
> __blkdev_put(bdev->bd_contains, mode, 1);
> bdev->bd_contains = NULL;
> out_unlock_bdev:
> - if (claiming)
> - bd_abort_claiming(bdev, claiming, holder);
> + if (!for_part && (mode & FMODE_EXCL))
> + bd_abort_claiming(bdev, holder);
> mutex_unlock(&bdev->bd_mutex);
> disk_unblock_events(disk);
> out_put_whole:
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 044d9dd159d882..696b2f9c5529d8 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1988,10 +1988,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
> struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
> void *holder);
> struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
> -int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
> - void *holder);
> -void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
> - void *holder);
> +int bd_prepare_to_claim(struct block_device *bdev, void *holder);
> +void bd_abort_claiming(struct block_device *bdev, void *holder);
> void blkdev_put(struct block_device *bdev, fmode_t mode);
>
> struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
> --
> 2.29.2
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-11-19 10:07 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 8:47 merge struct block_device and struct hd_struct Christoph Hellwig
2020-11-18 8:47 ` [PATCH 01/20] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats Christoph Hellwig
2020-11-18 14:09 ` Jan Kara
2020-11-19 8:37 ` Johannes Thumshirn
2020-11-24 12:26 ` Tejun Heo
2020-11-18 8:47 ` [PATCH 02/20] block: remove a duplicate __disk_get_part prototype Christoph Hellwig
2020-11-18 14:10 ` Jan Kara
2020-11-19 8:37 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 03/20] block: add a bdev_kobj helper Christoph Hellwig
2020-11-18 14:18 ` Jan Kara
2020-11-19 8:37 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 04/20] block: use disk_part_iter_exit in disk_part_iter_next Christoph Hellwig
2020-11-18 14:19 ` Jan Kara
2020-11-19 8:37 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 05/20] block: use put_device in put_disk Christoph Hellwig
2020-11-18 14:20 ` Jan Kara
2020-11-19 8:38 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 06/20] block: change the hash used for looking up block devices Christoph Hellwig
2020-11-18 14:22 ` Jan Kara
2020-11-18 8:47 ` [PATCH 07/20] init: refactor name_to_dev_t Christoph Hellwig
2020-11-18 14:37 ` Jan Kara
2020-11-19 7:52 ` Christoph Hellwig
2020-11-19 8:25 ` Jan Kara
2020-11-20 8:49 ` Christoph Hellwig
2020-11-19 8:38 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 08/20] init: refactor devt_from_partuuid Christoph Hellwig
2020-11-18 14:41 ` Jan Kara
2020-11-18 8:47 ` [PATCH 09/20] init: cleanup match_dev_by_uuid and match_dev_by_label Christoph Hellwig
2020-11-18 14:42 ` Jan Kara
2020-11-19 8:38 ` Johannes Thumshirn
2020-11-18 8:47 ` [PATCH 10/20] block: refactor __blkdev_put Christoph Hellwig
2020-11-18 14:46 ` Jan Kara
2020-11-18 8:47 ` [PATCH 11/20] block: reference struct block_device from struct hd_struct Christoph Hellwig
2020-11-19 9:41 ` Jan Kara
2020-11-20 8:56 ` Christoph Hellwig
2020-11-24 16:59 ` Tejun Heo
2020-11-25 11:40 ` Jan Kara
2020-11-25 12:09 ` Tejun Heo
2020-11-18 8:47 ` [PATCH 12/20] block: simplify the block device claiming interface Christoph Hellwig
2020-11-19 10:07 ` Jan Kara [this message]
2020-11-18 8:47 ` [PATCH 13/20] block: remove ->bd_contains Christoph Hellwig
2020-11-19 10:32 ` Jan Kara
2020-11-20 9:01 ` Christoph Hellwig
2020-11-18 8:47 ` [PATCH 14/20] block: remove the nr_sects field in struct hd_struct Christoph Hellwig
2020-11-19 12:05 ` Jan Kara
2020-11-20 9:08 ` Christoph Hellwig
2020-11-20 11:21 ` Jan Kara
2020-11-20 15:32 ` Christoph Hellwig
2020-11-20 15:59 ` Matthew Wilcox
2020-11-20 16:01 ` Christoph Hellwig
2020-11-20 20:05 ` Jan Kara
2020-11-21 16:24 ` Christoph Hellwig
2020-11-18 8:47 ` [PATCH 15/20] block: merge struct block_device and " Christoph Hellwig
2020-11-19 14:39 ` Jan Kara
2020-11-20 9:15 ` Christoph Hellwig
2020-11-20 10:53 ` Jan Kara
2020-11-18 8:47 ` [PATCH 16/20] block: stop using bdget_disk for partition 0 Christoph Hellwig
2020-11-19 14:43 ` Jan Kara
2020-11-18 8:47 ` [PATCH 17/20] filemap: consistently use ->f_mapping over ->i_mapping Christoph Hellwig
2020-11-19 14:53 ` Jan Kara
2020-11-19 15:13 ` Matthew Wilcox
2020-11-20 9:17 ` Christoph Hellwig
2020-11-18 8:47 ` [PATCH 18/20] fs: remove get_super_thawed and get_super_exclusive_thawed Christoph Hellwig
2020-11-19 14:59 ` Jan Kara
2020-11-18 8:47 ` [PATCH 19/20] bcache: remove a superflous lookup_bdev all Christoph Hellwig
2020-11-18 8:54 ` Coly Li
2020-11-18 9:10 ` Greg KH
2020-11-18 9:55 ` Coly Li
2020-11-18 16:24 ` Christoph Hellwig
2020-11-18 8:48 ` [PATCH 20/20] block: remove i_bdev Christoph Hellwig
2020-11-18 8:56 ` merge struct block_device and struct hd_struct Jan Beulich
2020-11-18 8:58 ` Christoph Hellwig
2020-11-18 9:04 ` Jan Beulich
2020-11-18 9:08 ` Christoph Hellwig
2020-11-18 9:09 ` Greg KH
2020-11-18 9:23 ` Jan Beulich
2020-11-18 9:32 ` Greg KH
2020-11-18 12:50 ` Matthew Wilcox
2020-11-18 9:13 ` Greg KH
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