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 09:54:21 +0000 (10:54 +0100)
commit25714ad6bf5e98025579fa4c08ff2041a663910c
treea8b38cccca7b4be22a0beea28e48632bbf0d23ce
parent75e2cfa5fae9474f84a2437b62a73a2ba0d2509f
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