On Thu 24-03-22 08:51:10, Christoph Hellwig wrote: > Add a helper that returns the openers for a given gendisk to avoid having > drivers poke into disk->part0 to get at this information in a somewhat > cumbersome way. > > Signed-off-by: Christoph Hellwig <hch@xxxxxx> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > --- > drivers/block/nbd.c | 4 ++-- > drivers/block/zram/zram_drv.c | 4 ++-- > include/linux/blkdev.h | 15 +++++++++++++++ > 3 files changed, 19 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 795f65a5c9661..93af7587d5ed6 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -1219,7 +1219,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) > > static void nbd_bdev_reset(struct nbd_device *nbd) > { > - if (nbd->disk->part0->bd_openers > 1) > + if (disk_openers(nbd->disk) > 1) > return; > set_capacity(nbd->disk, 0); > } > @@ -1578,7 +1578,7 @@ static void nbd_release(struct gendisk *disk, fmode_t mode) > struct nbd_device *nbd = disk->private_data; > > if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) && > - disk->part0->bd_openers == 0) > + disk_openers(disk) == 0) > nbd_disconnect_and_put(nbd); > > nbd_config_put(nbd); > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 863606f1722b1..2362385f782a9 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -1800,7 +1800,7 @@ static ssize_t reset_store(struct device *dev, > > mutex_lock(&disk->open_mutex); > /* Do not reset an active device or claimed device */ > - if (disk->part0->bd_openers || zram->claim) { > + if (disk_openers(disk) || zram->claim) { > mutex_unlock(&disk->open_mutex); > return -EBUSY; > } > @@ -1990,7 +1990,7 @@ static int zram_remove(struct zram *zram) > bool claimed; > > mutex_lock(&zram->disk->open_mutex); > - if (zram->disk->part0->bd_openers) { > + if (disk_openers(zram->disk)) { > mutex_unlock(&zram->disk->open_mutex); > return -EBUSY; > } > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index eb27312a1b8f3..9824ebc9b4d31 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -176,6 +176,21 @@ static inline bool disk_live(struct gendisk *disk) > return !inode_unhashed(disk->part0->bd_inode); > } > > +/** > + * disk_openers - returns how many openers are there for a disk > + * @disk: disk to check > + * > + * This returns the number of openers for a disk. Note that this value is only > + * stable if disk->open_mutex is held. > + * > + * Note: Due to a quirk in the block layer open code, each open partition is > + * only counted once even if there are multiple openers. > + */ > +static inline unsigned int disk_openers(struct gendisk *disk) > +{ > + return disk->part0->bd_openers; > +} > + > /* > * The gendisk is refcounted by the part0 block_device, and the bd_device > * therein is also used for device model presentation in sysfs. > -- > 2.30.2 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR