Re: [PATCH] net: mdio: octeon: Fix some double free issues

On Thu, May 13, 2021 at 09:24:55AM +0200, Christophe JAILLET wrote:

'bus->mii_bus' has been allocated with 'devm_mdiobus_alloc_size()' in the
probe function. So it must not be freed explicitly or there will be a
double free.

Remove the incorrect 'mdiobus_free' in the error handling path of the
probe function and in remove function.

Suggested-By: Andrew Lunn <andrew@lunn.ch>
Fixes: 35d2aeac9810 ("phy: mdio-octeon: Use devm_mdiobus_alloc_size()")
Signed-off-by: Christophe JAILLET <redacted>

Reviewed-by: Russell King <redacted>

---
The 'smi_en.u64 = 0; oct_mdio_writeq()' looks odd to me. Usually the normal
path and the error handling path don't write the same value. Here, both
write 0.
Having '1' somewhere would 'look' more usual. :)
More over I think that 'smi_en.s.en = 1;' in the probe is useless.

It looks fine to me.

        smi_en.u64 = 0;
        smi_en.s.en = 1;
        oct_mdio_writeq(smi_en.u64, bus->register_base + SMI_EN);

smi_en is a union of a u64 and a structure containing a bitfield. s.en
corresponds on LE systems with the u64 bit 0. So the above has the
effect of writing a u64 value of '1' to the SMI_EN register, whereas:

        smi_en.u64 = 0;
        oct_mdio_writeq(smi_en.u64, bus->register_base + SMI_EN);

has the effect of writing a u64 value of '0' to the SMI_EN register.

This code is fine.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!