4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 296dcc40f2f2e402facf7cd26cf3f2c8f4b17d47 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/swim3.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c index c1c676a33e4a..3f6df3f1f5d9 100644 --- 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);