block/swim3: Fix -EBUSY error when re-opening device after unmount

When the block device is opened with FMODE_EXCL, ref_count is set to -1.
This value doesn't get reset when the device is closed which means the
device cannot be opened again. Fix this by checking for refcount <= 0
in the release method.

Reported-and-tested-by: Stan Johnson <userm57@yahoo.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index ba1190f..87ca8f2 100644 (file)
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -995,7 +995,11 @@ static void floppy_release(struct gendisk *disk, fmode_t mode)
        struct swim3 __iomem *sw = fs->swim3;
 
        mutex_lock(&swim3_mutex);
-       if (fs->ref_count > 0 && --fs->ref_count == 0) {
+       if (fs->ref_count > 0)
+               --fs->ref_count;
+       else if (fs->ref_count == -1)
+               fs->ref_count = 0;
+       if (fs->ref_count == 0) {
                swim3_action(fs, MOTOR_OFF);
                out_8(&sw->control_bic, 0xff);
                swim3_select(fs, RELAX);