i2c: smbus: fix NULL function pointer dereference
Baruch reported an OOPS when using the designware controller as target
only. Target-only modes break the assumption of one transfer function
always being available. Fix this by always checking the pointer in
__i2c_transfer.
Reported-by: Baruch Siach <baruch@tkos.co.il>
Closes: https://lore.kernel.org/r/4269631780e5ba789cf1ae391eec1b959def7d99.1712761976.git.baruch@tkos.co.il
Fixes: 4b1acc4333
("i2c: core changes for slave support")
[wsa: dropped the simplification in core-smbus to avoid theoretical regressions]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Baruch Siach <baruch@tkos.co.il>
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@ -2200,13 +2200,18 @@ static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs,
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* Returns negative errno, else the number of messages executed.
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*
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* Adapter lock must be held when calling this function. No debug logging
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* takes place. adap->algo->master_xfer existence isn't checked.
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* takes place.
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*/
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int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
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{
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unsigned long orig_jiffies;
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int ret, try;
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if (!adap->algo->master_xfer) {
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dev_dbg(&adap->dev, "I2C level transfers not supported\n");
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return -EOPNOTSUPP;
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}
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if (WARN_ON(!msgs || num < 1))
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return -EINVAL;
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@ -2273,11 +2278,6 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
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{
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int ret;
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if (!adap->algo->master_xfer) {
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dev_dbg(&adap->dev, "I2C level transfers not supported\n");
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return -EOPNOTSUPP;
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}
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/* REVISIT the fault reporting model here is weak:
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*
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* - When we get an error after receiving N bytes from a slave,
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