ataflop: fix off by one in ataflop_probe()

[ 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>

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index aed2c2a4f4ea3f95de0849e43683c79a77ebf6e6..d601e49f80e07a10c76351c07d4c79e44d135705 100644 (file)
--- 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]) {