From bfa10b8c98bb335bc3e401d3ec947d446f04d1aa Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 18 May 2012 13:50:28 +0200 Subject: [PATCH] floppy: remove floppy-specific O_EXCL handling Block layer now handles O_EXCL in a generic way for block devices. The semantics is however different for floppy and all other block devices, as floppy driver contains its own O_EXCL handling. The semantics for all-but-floppy bdevs is "there can be at most one O_EXCL open of this file", while for floppy bdev the semantics is "if someone has the bdev open with O_EXCL, noone else can open it". There is actual userspace-observable change in behavior because of this since commit e525fd89d380c ("block: make blkdev_get/put() handle exclusive access") -- on kernels containing this commit, mount of /dev/fd0 causes the fd0 block device be claimed with _EXCL, preventing subsequent open(/dev/fd0). Bring things back into shape, i.e. make it possible, analogically to other block devices, to mount the floppy and open() it afterwards -- remove the floppy-specific handling and let the generic bdev code O_EXCL handling take over. Signed-off-by: Jiri Kosina Acked-by: Tejun Heo Acked-by: NeilBrown Signed-off-by: Andrew Morton Signed-off-by: Jiri Kosina --- drivers/block/floppy.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 48e1d70740dc..cce7df367b79 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3607,9 +3607,7 @@ static int floppy_release(struct gendisk *disk, fmode_t mode) mutex_lock(&floppy_mutex); mutex_lock(&open_lock); - if (UDRS->fd_ref < 0) - UDRS->fd_ref = 0; - else if (!UDRS->fd_ref--) { + if (!UDRS->fd_ref--) { DPRINT("floppy_release with fd_ref == 0"); UDRS->fd_ref = 0; } @@ -3645,13 +3643,7 @@ static int floppy_open(struct block_device *bdev, fmode_t mode) set_bit(FD_VERIFY_BIT, &UDRS->flags); } - if (UDRS->fd_ref == -1 || (UDRS->fd_ref && (mode & FMODE_EXCL))) - goto out2; - - if (mode & FMODE_EXCL) - UDRS->fd_ref = -1; - else - UDRS->fd_ref++; + UDRS->fd_ref++; opened_bdev[drive] = bdev; @@ -3714,10 +3706,8 @@ static int floppy_open(struct block_device *bdev, fmode_t mode) mutex_unlock(&floppy_mutex); return 0; out: - if (UDRS->fd_ref < 0) - UDRS->fd_ref = 0; - else - UDRS->fd_ref--; + UDRS->fd_ref--; + if (!UDRS->fd_ref) opened_bdev[drive] = NULL; out2: -- 2.39.2