[PATCH 5.11 387/601] ataflop: fix off by one in ataflop_probe()

Greg Kroah-Hartman
2021-05-12T17:41:43Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit b777f4c47781df6b23e3f4df6fdb92d9aceac7bb ]

Smatch complains that the "type > NUM_DISK_MINORS" should be >=
instead of >. We also need to subtract one from "type" at the start.

Fixes: bf9c0538e485 ("ataflop: use a separate gendisk for each media format")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/ataflop.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index aed2c2a4f4ea..d601e49f80e0 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -2001,7 +2001,10 @@ static void ataflop_probe(dev_t dev)
int drive = MINOR(dev) & 3;
int type = MINOR(dev) >> 2;

- if (drive >= FD_MAX_UNITS || type > NUM_DISK_MINORS)
+ if (type)
+ type--;
+
+ if (drive >= FD_MAX_UNITS || type >= NUM_DISK_MINORS)
return;
mutex_lock(&ataflop_probe_lock);
if (!unit[drive].disk[type]) {
--
2.30.2