On Tue, Mar 23, 2021 at 02:14:18PM -0500, Pierre-Louis Bossart wrote: > > > On 3/23/21 1:32 PM, Greg KH wrote: > > On Tue, Mar 23, 2021 at 01:04:49PM -0500, Pierre-Louis Bossart wrote: > > > > > > > > Note that the auxiliary bus API has separate init and add steps, which > > > > > requires more attention in the error unwinding paths. The main loop > > > > > needs to deal with kfree() and auxiliary_device_uninit() for the > > > > > current iteration before jumping to the common label which releases > > > > > everything allocated in prior iterations. > > > > > > > > The init/add steps can be moved together in the aux bus code if that > > > > makes this usage simpler. Please do that instead. > > > > > > IIRC the two steps were separated during the auxbus reviews to allow the > > > parent to call kfree() on an init failure, and auxiliary_device_uninit() > > > afterwards. > > > > > > https://www.kernel.org/doc/html/latest/driver-api/auxiliary_bus.html#auxiliary-device > > > > > > With a single auxbus_register(), the parent wouldn't know whether to use > > > kfree() or auxiliary_device_uinit() when an error is returned, would it? > > > > > > > It should, you know the difference when you call device_register() vs. > > device_initialize()/device_add(), for what to do, right? > > > > Should be no difference here either :) > > sorry, not following. > > with the regular devices, the errors can only happen on the second "add" > stage. > > int device_register(struct device *dev) > { > device_initialize(dev); > return device_add(dev); > } > > that's not what is currently implemented for the auxiliary bus > > the current flow is > > ldev = kzalloc(..) > some inits > ret = auxiliary_device_init(&ldev->auxdev) > if (ret < 0) { > kfree(ldev); > goto err1; > } > > ret = auxiliary_device_add(&ldev->auxdev) > if (ret < 0) > auxiliary_device_uninit(&ldev->auxdev) > goto err2; > } > ... > err2: > err1: > > How would I convert this to > > ldev = kzalloc(..) > some inits > ret = auxiliary_device_register() > if (ret) { > kfree(ldev) or not? > unit or not? > } > > IIRC during reviews there was an ask that the parent and name be checked, > and that's why the code added the two checks below: > > int auxiliary_device_init(struct auxiliary_device *auxdev) > { > struct device *dev = &auxdev->dev; > > if (!dev->parent) { > pr_err("auxiliary_device has a NULL dev->parent\n"); > return -EINVAL; > } > > if (!auxdev->name) { > pr_err("auxiliary_device has a NULL name\n"); > return -EINVAL; > } > > dev->bus = &auxiliary_bus_type; > device_initialize(&auxdev->dev); > return 0; > } > > does this clarify the sequence? Yes, thanks, but I don't know the answer to your question, sorry. This feels more complex than it should be, but I do not have the time at the moment to look into it, sorry. Try getting the authors of this code to fix it up :) thanks, greg k-h
