diff options
| author | Heiner Kallweit <hkallweit1@gmail.com> | 2023-09-09 22:25:06 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2023-09-19 10:56:27 +0200 |
| commit | f78ca48a8ba9cdec96e8839351e49eec3233b177 (patch) | |
| tree | fa13578213a1621b69aa4eebff6748915a250a91 /drivers/i2c/busses | |
| parent | ce9ecca0238b140b88f43859b211c9fdfd8e5b70 (diff) | |
| download | linux-f78ca48a8ba9cdec96e8839351e49eec3233b177.tar.gz | |
i2c: i801: fix potential race in i801_block_transaction_byte_by_byte
Currently we set SMBHSTCNT_LAST_BYTE only after the host has started
receiving the last byte. If we get e.g. preempted before setting
SMBHSTCNT_LAST_BYTE, the host may be finished with receiving the byte
before SMBHSTCNT_LAST_BYTE is set.
Therefore change the code to set SMBHSTCNT_LAST_BYTE before writing
SMBHSTSTS_BYTE_DONE for the byte before the last byte. Now the code
is also consistent with what we do in i801_isr_byte_done().
Reported-by: Jean Delvare <jdelvare@suse.com>
Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/
Cc: stable@vger.kernel.org
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers/i2c/busses')
| -rw-r--r-- | drivers/i2c/busses/i2c-i801.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 73ae064321331d..f53be242f3b79b 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -679,15 +679,11 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, return result ? priv->status : -ETIMEDOUT; } - for (i = 1; i <= len; i++) { - if (i == len && read_write == I2C_SMBUS_READ) - smbcmd |= SMBHSTCNT_LAST_BYTE; - outb_p(smbcmd, SMBHSTCNT(priv)); - - if (i == 1) - outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START, - SMBHSTCNT(priv)); + if (len == 1 && read_write == I2C_SMBUS_READ) + smbcmd |= SMBHSTCNT_LAST_BYTE; + outb_p(smbcmd | SMBHSTCNT_START, SMBHSTCNT(priv)); + for (i = 1; i <= len; i++) { status = i801_wait_byte_done(priv); if (status) return status; @@ -710,9 +706,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, data->block[0] = len; } - /* Retrieve/store value in SMBBLKDAT */ - if (read_write == I2C_SMBUS_READ) + if (read_write == I2C_SMBUS_READ) { data->block[i] = inb_p(SMBBLKDAT(priv)); + if (i == len - 1) + outb_p(smbcmd | SMBHSTCNT_LAST_BYTE, SMBHSTCNT(priv)); + } + if (read_write == I2C_SMBUS_WRITE && i+1 <= len) outb_p(data->block[i+1], SMBBLKDAT(priv)); |