Replace the per-block device bd_mutex with a per-gendisk open_mutex, thus simplifying locking wherever we deal with partitions. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- Documentation/filesystems/locking.rst | 2 +- block/genhd.c | 7 ++--- block/partitions/core.c | 24 ++++++++--------- drivers/block/loop.c | 14 +++++----- drivers/block/xen-blkfront.c | 8 +++--- drivers/block/zram/zram_drv.c | 18 ++++++------- drivers/block/zram/zram_drv.h | 2 +- drivers/md/md.h | 6 ++--- drivers/s390/block/dasd_genhd.c | 8 +++--- drivers/scsi/sd.c | 4 +-- fs/block_dev.c | 37 +++++++++++---------------- fs/btrfs/volumes.c | 2 +- fs/super.c | 8 +++--- include/linux/blk_types.h | 1 - include/linux/genhd.h | 3 +++ 15 files changed, 68 insertions(+), 76 deletions(-) diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 1e894480115b..2183fd8cc350 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -480,7 +480,7 @@ prototypes:: locking rules: ======================= =================== -ops bd_mutex +ops open_mutex ======================= =================== open: yes release: yes diff --git a/block/genhd.c b/block/genhd.c index 39ca97b0edc6..8b88e99f6675 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -615,9 +615,9 @@ void del_gendisk(struct gendisk *disk) */ down_write(&bdev_lookup_sem); - mutex_lock(&disk->part0->bd_mutex); + mutex_lock(&disk->open_mutex); blk_drop_partitions(disk); - mutex_unlock(&disk->part0->bd_mutex); + mutex_unlock(&disk->open_mutex); fsync_bdev(disk->part0); __invalidate_device(disk->part0, true); @@ -1304,6 +1304,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id) goto out_free_disk; disk->node_id = node_id; + mutex_init(&disk->open_mutex); xa_init(&disk->part_tbl); if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL)) goto out_destroy_part_tbl; @@ -1521,7 +1522,7 @@ void disk_unblock_events(struct gendisk *disk) * doesn't clear the events from @disk->ev. * * CONTEXT: - * If @mask is non-zero must be called with bdev->bd_mutex held. + * If @mask is non-zero must be called with disk->open_mutex held. */ void disk_flush_events(struct gendisk *disk, unsigned int mask) { diff --git a/block/partitions/core.c b/block/partitions/core.c index dc60ecf46fe6..0d33f55a7d78 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -282,7 +282,7 @@ struct device_type part_type = { }; /* - * Must be called either with bd_mutex held, before a disk can be opened or + * Must be called either with open_mutex held, before a disk can be opened or * after all disk users are gone. */ static void delete_partition(struct block_device *part) @@ -311,7 +311,7 @@ static ssize_t whole_disk_show(struct device *dev, static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL); /* - * Must be called either with bd_mutex held, before a disk can be opened or + * Must be called either with open_mutex held, before a disk can be opened or * after all disk users are gone. */ static struct block_device *add_partition(struct gendisk *disk, int partno, @@ -450,15 +450,15 @@ int bdev_add_partition(struct block_device *bdev, int partno, { struct block_device *part; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); if (partition_overlaps(bdev->bd_disk, start, length, -1)) { - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return -EBUSY; } part = add_partition(bdev->bd_disk, partno, start, length, ADDPART_FLAG_NONE, NULL); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return PTR_ERR_OR_ZERO(part); } @@ -471,8 +471,7 @@ int bdev_del_partition(struct block_device *bdev, int partno) if (!part) return -ENXIO; - mutex_lock(&part->bd_mutex); - mutex_lock_nested(&bdev->bd_mutex, 1); + mutex_lock(&bdev->bd_disk->open_mutex); ret = -EBUSY; if (part->bd_openers) @@ -481,8 +480,7 @@ int bdev_del_partition(struct block_device *bdev, int partno) delete_partition(part); ret = 0; out_unlock: - mutex_unlock(&bdev->bd_mutex); - mutex_unlock(&part->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); bdput(part); return ret; } @@ -497,8 +495,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno, if (!part) return -ENXIO; - mutex_lock(&part->bd_mutex); - mutex_lock_nested(&bdev->bd_mutex, 1); + mutex_lock(&bdev->bd_disk->open_mutex); ret = -EINVAL; if (start != part->bd_start_sect) goto out_unlock; @@ -511,8 +508,7 @@ int bdev_resize_partition(struct block_device *bdev, int partno, ret = 0; out_unlock: - mutex_unlock(&part->bd_mutex); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); bdput(part); return ret; } @@ -538,7 +534,7 @@ void blk_drop_partitions(struct gendisk *disk) struct block_device *part; unsigned long idx; - lockdep_assert_held(&disk->part0->bd_mutex); + lockdep_assert_held(&disk->open_mutex); xa_for_each_start(&disk->part_tbl, idx, part, 1) { if (!bdgrab(part)) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index d58d68f3c7cd..95c570f5923f 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -652,9 +652,9 @@ static void loop_reread_partitions(struct loop_device *lo, { int rc; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); rc = bdev_disk_changed(bdev, false); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_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); @@ -747,7 +747,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, mutex_unlock(&lo->lo_mutex); /* * We must drop file reference outside of lo_mutex as dropping - * the file ref can take bd_mutex which creates circular locking + * the file ref can take open_mutex which creates circular locking * dependency. */ fput(old_file); @@ -1260,7 +1260,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) mutex_unlock(&lo->lo_mutex); if (partscan) { /* - * bd_mutex has been held already in release path, so don't + * open_mutex has been held already in release path, so don't * acquire it if this function is called in such case. * * If the reread partition isn't from release path, lo_refcnt @@ -1268,10 +1268,10 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) * current holder is released. */ if (!release) - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); err = bdev_disk_changed(bdev, false); if (!release) - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); if (err) pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", __func__, lo_number, err); @@ -1298,7 +1298,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) /* * Need not hold lo_mutex to fput backing file. Calling fput holding * lo_mutex triggers a circular lock dependency possibility warning as - * fput can take bd_mutex which is usually taken before lo_mutex. + * fput can take open_mutex which is usually taken before lo_mutex. */ if (filp) fput(filp); diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 10df39a8b18d..f2c1aedcdf5a 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2163,7 +2163,7 @@ static void blkfront_closing(struct blkfront_info *info) return; } - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); if (bdev->bd_openers) { xenbus_dev_error(xbdev, -EBUSY, @@ -2174,7 +2174,7 @@ static void blkfront_closing(struct blkfront_info *info) xenbus_frontend_closed(xbdev); } - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); bdput(bdev); } @@ -2531,7 +2531,7 @@ static int blkfront_remove(struct xenbus_device *xbdev) * isn't closed yet, we let release take care of it. */ - mutex_lock(&bdev->bd_mutex); + mutex_lock(&disk->open_mutex); info = disk->private_data; dev_warn(disk_to_dev(disk), @@ -2546,7 +2546,7 @@ static int blkfront_remove(struct xenbus_device *xbdev) mutex_unlock(&blkfront_mutex); } - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&disk->open_mutex); bdput(bdev); return 0; diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index cf8deecc39ef..b3bf544493d3 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1781,24 +1781,24 @@ static ssize_t reset_store(struct device *dev, zram = dev_to_zram(dev); bdev = zram->disk->part0; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); /* Do not reset an active device or claimed device */ if (bdev->bd_openers || zram->claim) { - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return -EBUSY; } /* From now on, anyone can't open /dev/zram[0-9] */ zram->claim = true; - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); /* Make sure all the pending I/O are finished */ fsync_bdev(bdev); zram_reset_device(zram); - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); zram->claim = false; - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return len; } @@ -1808,7 +1808,7 @@ 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)); + WARN_ON(!mutex_is_locked(&bdev->bd_disk->open_mutex)); zram = bdev->bd_disk->private_data; /* zram was claimed to reset so open request fails */ @@ -1982,14 +1982,14 @@ static int zram_remove(struct zram *zram) { struct block_device *bdev = zram->disk->part0; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); if (bdev->bd_openers || zram->claim) { - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return -EBUSY; } zram->claim = true; - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); zram_debugfs_unregister(zram); diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 419a7e8281ee..74c411911b6e 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -112,7 +112,7 @@ struct zram { /* * zram is claimed so open request will be failed */ - bool claim; /* Protected by bdev->bd_mutex */ + bool claim; /* Protected by disk->open_mutex */ struct file *backing_dev; #ifdef CONFIG_ZRAM_WRITEBACK spinlock_t wb_limit_lock; diff --git a/drivers/md/md.h b/drivers/md/md.h index fb7eab58cfd5..a88086d4110c 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -395,10 +395,10 @@ struct mddev { * that we are never stopping an array while it is open. * 'reconfig_mutex' protects all other reconfiguration. * These locks are separate due to conflicting interactions - * with bdev->bd_mutex. + * with disk->open_mutex. * Lock ordering is: - * reconfig_mutex -> bd_mutex - * bd_mutex -> open_mutex: e.g. __blkdev_get -> md_open + * reconfig_mutex -> disk->open_mutex + * disk->open_mutex -> open_mutex: e.g. __blkdev_get -> md_open */ struct mutex open_mutex; struct mutex reconfig_mutex; diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c index 8d6587ec73e2..bf2082d461c7 100644 --- a/drivers/s390/block/dasd_genhd.c +++ b/drivers/s390/block/dasd_genhd.c @@ -109,9 +109,9 @@ int dasd_scan_partitions(struct dasd_block *block) return -ENODEV; } - mutex_lock(&bdev->bd_mutex); + mutex_lock(&block->gdp->open_mutex); rc = bdev_disk_changed(bdev, false); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&block->gdp->open_mutex); if (rc) DBF_DEV_EVENT(DBF_ERR, block->base, "scan partitions error, rc %d", rc); @@ -145,9 +145,9 @@ void dasd_destroy_partitions(struct dasd_block *block) bdev = block->bdev; block->bdev = NULL; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); bdev_disk_changed(bdev, true); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); /* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */ blkdev_put(bdev, FMODE_READ); diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index cb3c37d1e009..d3ff723af879 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1400,7 +1400,7 @@ static void sd_uninit_command(struct scsi_cmnd *SCpnt) * In the latter case @inode and @filp carry an abridged amount * of information as noted above. * - * Locking: called with bdev->bd_mutex held. + * Locking: called with bdev->bd_disk->open_mutex held. **/ static int sd_open(struct block_device *bdev, fmode_t mode) { @@ -1476,7 +1476,7 @@ static int sd_open(struct block_device *bdev, fmode_t mode) * Note: may block (uninterruptible) if error recovery is underway * on this disk. * - * Locking: called with bdev->bd_mutex held. + * Locking: called with bdev->bd_disk->open_mutex held. **/ static void sd_release(struct gendisk *disk, fmode_t mode) { diff --git a/fs/block_dev.c b/fs/block_dev.c index 95fde785dae7..3597532cc081 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -895,7 +895,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) mapping_set_gfp_mask(&inode->i_data, GFP_USER); bdev = I_BDEV(inode); - mutex_init(&bdev->bd_mutex); mutex_init(&bdev->bd_fsfreeze_mutex); spin_lock_init(&bdev->bd_size_lock); bdev->bd_disk = disk; @@ -1154,7 +1153,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) struct bd_holder_disk *holder; int ret = 0; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); WARN_ON_ONCE(!bdev->bd_holder); @@ -1199,7 +1198,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) out_free: kfree(holder); out_unlock: - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); return ret; } EXPORT_SYMBOL_GPL(bd_link_disk_holder); @@ -1218,7 +1217,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) { struct bd_holder_disk *holder; - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); holder = bd_find_holder_disk(bdev, disk); @@ -1230,7 +1229,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) kfree(holder); } - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); } EXPORT_SYMBOL_GPL(bd_unlink_disk_holder); #endif @@ -1242,7 +1241,7 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate) struct gendisk *disk = bdev->bd_disk; int ret = 0; - lockdep_assert_held(&bdev->bd_mutex); + lockdep_assert_held(&disk->open_mutex); rescan: if (bdev->bd_part_count) @@ -1324,14 +1323,10 @@ static int blkdev_get_part(struct block_device *part, fmode_t mode) goto done; whole = bdgrab(disk->part0); - mutex_lock_nested(&whole->bd_mutex, 1); ret = blkdev_get_whole(whole, mode); - if (ret) { - mutex_unlock(&whole->bd_mutex); + if (ret) goto out_put_whole; - } whole->bd_part_count++; - mutex_unlock(&whole->bd_mutex); ret = -ENXIO; if (!(disk->flags & GENHD_FL_UP) || !bdev_nr_sectors(part)) @@ -1441,7 +1436,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) disk_block_events(disk); - mutex_lock(&bdev->bd_mutex); + mutex_lock(&disk->open_mutex); if (bdev_is_partition(bdev)) ret = blkdev_get_part(bdev, mode); else @@ -1464,7 +1459,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) unblock_events = false; } } - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&disk->open_mutex); if (unblock_events) disk_unblock_events(disk); @@ -1473,7 +1468,7 @@ struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder) abort_claiming: if (mode & FMODE_EXCL) bd_abort_claiming(bdev, holder); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&disk->open_mutex); disk_unblock_events(disk); put_blkdev: blkdev_put_no_open(bdev); @@ -1553,7 +1548,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) struct gendisk *disk = bdev->bd_disk; struct block_device *victim = NULL; - mutex_lock_nested(&bdev->bd_mutex, for_part); if (for_part) bdev->bd_part_count--; @@ -1568,7 +1562,6 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) if (!bdev_is_partition(bdev) && disk->fops->release) disk->fops->release(disk, mode); - mutex_unlock(&bdev->bd_mutex); if (victim) { __blkdev_put(victim, mode, 1); bdput(victim); @@ -1589,15 +1582,14 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) if (bdev->bd_openers == 1) sync_blockdev(bdev); - mutex_lock(&bdev->bd_mutex); - + mutex_lock(&disk->open_mutex); if (mode & FMODE_EXCL) { struct block_device *whole = bdev_whole(bdev); bool bdev_free; /* * Release a claim on the device. The holder fields - * are protected with bdev_lock. bd_mutex is to + * are protected with bdev_lock. open_mutex is to * synchronize disk_holder unlinking. */ spin_lock(&bdev_lock); @@ -1628,9 +1620,10 @@ void blkdev_put(struct block_device *bdev, fmode_t mode) * from userland - e.g. eject(1). */ disk_flush_events(disk, DISK_EVENT_MEDIA_CHANGE); - mutex_unlock(&bdev->bd_mutex); __blkdev_put(bdev, mode, 0); + mutex_unlock(&disk->open_mutex); + blkdev_put_no_open(bdev); } EXPORT_SYMBOL(blkdev_put); @@ -1937,10 +1930,10 @@ void iterate_bdevs(void (*func)(struct block_device *, void *), void *arg) old_inode = inode; bdev = I_BDEV(inode); - mutex_lock(&bdev->bd_mutex); + mutex_lock(&bdev->bd_disk->open_mutex); if (bdev->bd_openers) func(bdev, arg); - mutex_unlock(&bdev->bd_mutex); + mutex_unlock(&bdev->bd_disk->open_mutex); spin_lock(&blockdev_superblock->s_inode_list_lock); } diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 9a1ead0c4a31..0f35bf7030ac 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1247,7 +1247,7 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, lockdep_assert_held(&uuid_mutex); /* * The device_list_mutex cannot be taken here in case opening the - * underlying device takes further locks like bd_mutex. + * underlying device takes further locks like open_mutex. * * We also don't need the lock here as this is called during mount and * exclusion is provided by uuid_mutex diff --git a/fs/super.c b/fs/super.c index 11b7e7213fd1..91b7f156735b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -1277,9 +1277,9 @@ int get_tree_bdev(struct fs_context *fc, } /* - * s_umount nests inside bd_mutex during + * s_umount nests inside open_mutex during * __invalidate_device(). blkdev_put() acquires - * bd_mutex and can't be called under s_umount. Drop + * open_mutex and can't be called under s_umount. Drop * s_umount temporarily. This is safe as we're * holding an active reference. */ @@ -1352,9 +1352,9 @@ struct dentry *mount_bdev(struct file_system_type *fs_type, } /* - * s_umount nests inside bd_mutex during + * s_umount nests inside open_mutex during * __invalidate_device(). blkdev_put() acquires - * bd_mutex and can't be called under s_umount. Drop + * open_mutex and can't be called under s_umount. Drop * s_umount temporarily. This is safe as we're * holding an active reference. */ diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index db026b6ec15a..a09660671fa4 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -29,7 +29,6 @@ struct block_device { int bd_openers; struct inode * bd_inode; /* will die */ struct super_block * bd_super; - struct mutex bd_mutex; /* open/close mutex */ void * bd_claiming; struct device bd_device; void * bd_holder; diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 7e9660ea967d..0747f1853f39 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -153,6 +153,9 @@ struct gendisk { unsigned long state; #define GD_NEED_PART_SCAN 0 #define GD_READ_ONLY 1 + + struct mutex open_mutex; /* open/close mutex */ + struct kobject *slave_dir; struct timer_rand_state *random; -- 2.30.2