From 37c3fc9abb25cd767ad5b048358336ac89488c16 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 25 Nov 2020 21:20:08 +0100 Subject: [PATCH] block: simplify the block device claiming interface Stop passing the whole device as a separate argument given that it can be trivially deducted and cleanup the !holder debug check. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman Reviewed-by: Jan Kara Reviewed-by: Hannes Reinecke Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- drivers/block/loop.c | 12 +++++----- fs/block_dev.c | 51 +++++++++++++++--------------------------- include/linux/blkdev.h | 6 ++--- 3 files changed, 25 insertions(+), 44 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index c0df88b3300c..d643c67be6ac 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1069,7 +1069,6 @@ 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; @@ -1088,8 +1087,7 @@ 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_whole(bdev); - error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure); + error = bd_prepare_to_claim(bdev, loop_configure); if (error) goto out_putf; } @@ -1176,15 +1174,15 @@ 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 94baee369d26..0569f5ebeb6f 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_whole(bdev); - 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); @@ -978,7 +974,6 @@ 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 @@ -988,9 +983,12 @@ 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_whole(bdev); + + if (WARN_ON_ONCE(!holder)) + return -EINVAL; retry: spin_lock(&bdev_lock); /* if someone else claimed, fail */ @@ -1030,15 +1028,15 @@ 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_whole(bdev); + spin_lock(&bdev_lock); BUG_ON(!bd_may_claim(bdev, whole, holder)); /* @@ -1063,11 +1061,10 @@ 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_whole(bdev), holder); spin_unlock(&bdev_lock); } EXPORT_SYMBOL(bd_abort_claiming); @@ -1487,7 +1484,6 @@ void blkdev_put_no_open(struct block_device *bdev) */ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) { - struct block_device *claiming; bool unblock_events = true; struct block_device *bdev; struct gendisk *disk; @@ -1510,15 +1506,9 @@ retry: disk = bdev->bd_disk; if (mode & FMODE_EXCL) { - WARN_ON_ONCE(!holder); - - ret = -ENOMEM; - claiming = bdget_disk(disk, 0); - if (!claiming) - goto put_blkdev; - ret = bd_prepare_to_claim(bdev, claiming, holder); + ret = bd_prepare_to_claim(bdev, holder); if (ret) - goto put_claiming; + goto put_blkdev; } disk_block_events(disk); @@ -1528,7 +1518,7 @@ retry: if (ret) goto abort_claiming; if (mode & FMODE_EXCL) { - bd_finish_claiming(bdev, claiming, holder); + bd_finish_claiming(bdev, holder); /* * Block event polling for write claims if requested. Any write @@ -1547,18 +1537,13 @@ retry: if (unblock_events) disk_unblock_events(disk); - if (mode & FMODE_EXCL) - bdput(claiming); return bdev; abort_claiming: if (mode & FMODE_EXCL) - bd_abort_claiming(bdev, claiming, holder); + bd_abort_claiming(bdev, holder); mutex_unlock(&bdev->bd_mutex); disk_unblock_events(disk); -put_claiming: - if (mode & FMODE_EXCL) - bdput(claiming); put_blkdev: blkdev_put_no_open(bdev); if (ret == -ERESTARTSYS) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 5d48b92f5e43..43a25d855e04 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); /* just for blk-cgroup, don't use elsewhere */