i2c: bail out early when RDWR parameters are wrong

[ Upstream commit 71581562ee36032d2d574a9b23ad4af6d6a64cf7 ]

The buggy parameters currently get caught later, but emit a noisy WARN.
Userspace should not be able to trigger this, so add similar checks much
earlier. Also avoids some unneeded code paths, of course. Apply kernel
coding stlye to a comment while here.

Reported-by: syzbot+ffb0b3ffa6cfbc7d7b3f@syzkaller.appspotmail.com
Tested-by: syzbot+ffb0b3ffa6cfbc7d7b3f@syzkaller.appspotmail.com
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
1 file changed