On Sat, 09 Jun 2007 20:21:18 +0400
Vitaly Bordug <[email protected]> wrote:
>
> device_bind_driver() error code returning has been fixed.
> release() function has been written, so that to free resources
> in correct way; the release path is now clean.
>
> Before the rework, it used to cause
> Device 'fixed@100:1' does not have a release() function, it is broken
> and must be fixed.
> BUG: at drivers/base/core.c:104 device_release()
>
> Call Trace:
> [<ffffffff802ec380>] kobject_cleanup+0x53/0x7e
> [<ffffffff802ec3ab>] kobject_release+0x0/0x9
> [<ffffffff802ecf3f>] kref_put+0x74/0x81
> [<ffffffff8035493b>] fixed_mdio_register_device+0x230/0x265
> [<ffffffff80564d31>] fixed_init+0x1f/0x35
> [<ffffffff802071a4>] init+0x147/0x2fb
> [<ffffffff80223b6e>] schedule_tail+0x36/0x92
> [<ffffffff8020a678>] child_rip+0xa/0x12
> [<ffffffff80311714>] acpi_ds_init_one_object+0x0/0x83
> [<ffffffff8020705d>] init+0x0/0x2fb
> [<ffffffff8020a66e>] child_rip+0x0/0x12
>
>
> Also changed the notation of the fixed phy definition on
> mdio bus to the form of <speed>+<duplex> to make it able to be used by
> gianfar and ucc_geth that define phy_id strictly as "%d:%d"
>
>
> static int fixed_mdio_register_device(int number, int speed, int duplex)
> {
> @@ -221,6 +238,12 @@ static int fixed_mdio_register_device(int number, int speed, int duplex)
> }
>
> fixed->regs = kzalloc(MII_REGS_NUM*sizeof(int), GFP_KERNEL);
> + if (NULL == fixed->regs) {
> + kfree(dev);
> + kfree(new_bus);
> + kfree(fixed);
> + return -ENOMEM;
> + }
> fixed->regs_num = MII_REGS_NUM;
> fixed->phy_status.speed = speed;
> fixed->phy_status.duplex = duplex;
> @@ -249,57 +272,43 @@ static int fixed_mdio_register_device(int number, int speed, int duplex)
> fixed->phydev = phydev;
>
> if(NULL == phydev) {
> - err = -ENOMEM;
> - goto device_create_fail;
> + kfree(dev);
> + kfree(new_bus);
> + kfree(fixed->regs);
> + kfree(fixed);
> + return -ENOMEM;
> }
>
> phydev->irq = PHY_IGNORE_INTERRUPT;
> phydev->dev.bus = &mdio_bus_type;
>
> - if(number)
> - snprintf(phydev->dev.bus_id, BUS_ID_SIZE,
> - "fixed_%d@%d:%d", number, speed, duplex);
> - else
> - snprintf(phydev->dev.bus_id, BUS_ID_SIZE,
> - "fixed@%d:%d", speed, duplex);
> + snprintf(phydev->dev.bus_id, BUS_ID_SIZE,
> + "%d:%d", number, speed + duplex);
> +
> phydev->bus = new_bus;
>
> + phydev->dev.driver = &fixed_mdio_driver.driver;
> + phydev->dev.release = fixed_mdio_release;
> +
> + err = phydev->dev.driver->probe(&phydev->dev);
> + if(err < 0) {
> + printk(KERN_ERR "Phy %s: problems with fixed driver\n",
> + phydev->dev.bus_id);
> + kfree(phydev);
> + kfree(dev);
> + kfree(new_bus);
> + kfree(fixed->regs);
> + kfree(fixed);
> + return err;
> + }
This is pretty fragile code. It would be better to consolidate all the
cleanup in a single spot at the end of fixed_mdio_register_device() and to
then employ the usual `goto err_foo;' technique.
Generally, embedding multiple return points into a large function like this
is a thing we prefer to avoid: it increases the risk that later changes will
introduce resource leaks, locking errors, etc.
Also, the
if (NULL == some_ptr)
thing does look rather weird. It is normally done to force a compile error
if someone uses "=" instead of "==", but gcc will warn about that anyway,
so it isn't really needed.
-
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