i2c: i801: Don't silently correct invalid transfer size
authorHeiner Kallweit <hkallweit1@gmail.com>
Sun, 7 Nov 2021 21:57:00 +0000 (22:57 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 27 Jan 2022 08:00:58 +0000 (09:00 +0100)
commit202d0e22fe512df0f1cb6253d40ce1058e373247
tree429637f0ca55a12eca8d9fd48b5d70f04f949a67
parentbb0304a352c2ebee5ee140ad08910746add9bbd9
i2c: i801: Don't silently correct invalid transfer size

[ Upstream commit effa453168a7eeb8a562ff4edc1dbf9067360a61 ]

If an invalid block size is provided, reject it instead of silently
changing it to a supported value. Especially critical I see the case of
a write transfer with block length 0. In this case we have no guarantee
that the byte we would write is valid. When silently reducing a read to
32 bytes then we don't return an error and the caller may falsely
assume that we returned the full requested data.

If this change should break any (broken) caller, then I think we should
fix the caller.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/i2c/busses/i2c-i801.c