Messages in this thread | | | Date | Wed, 3 Feb 2016 08:02:35 -0800 | From | Jarkko Sakkinen <> | Subject | Re: [tpmdd-devel] [PATCH] tpm: fix rollback/cleanup before tpm_chip_register() |
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On Tue, Feb 02, 2016 at 04:13:53PM -0700, Jason Gunthorpe wrote: > On Sat, Jan 30, 2016 at 06:05:42PM -0800, Jarkko Sakkinen wrote: > > The release-callback is not used before the device is attached to the > > device hierarchy. This caused resources not to cleanup properly if the > > device driver initialization failed before tpm_chip_register(). > > This commentary is not right, the release callback is callable > immediately after device_initialize returns, it will be called by the > last put_device().
Ah, right.
> > - * tpmm_chip_alloc() - allocate a new struct tpm_chip instance > > - * @dev: device to which the chip is associated > > + * tpmm_chip_alloc() - allocate and initialize a TPM chip > > + * @pdev: the platform device who is the parent of the chip > > ? A platform device is not required, just something in a state that > can handle devm.
Platform device in a generic sense like like ACPI or PNP device or something else. How would you call it instead? I want to call the parameter something else than 'dev' solely for readability.
Would s/the platform device/the parent device/ be better?
> > + /* Associate character device with the platform device only after > > + * it is properly initialized. > > + */ > > + dev_set_drvdata(pdev, chip); > > + devm_add_action(pdev, (void (*)(void *)) tpm_dev_release, > > &chip->dev); > > No, a release function can never be called naked. The action needs > to do put_device, which is the error unwind for device_initialize().
Got it (already from your first comment)!
What does "called naked" even mean? I just don't understand the english here and want to be sure that I understand what you are saying and not make false assumptions.
> > @@ -162,7 +165,10 @@ static int tpm_add_char_device(struct tpm_chip *chip) > > MINOR(chip->dev.devt), rc); > > > > cdev_del(&chip->cdev); > > - return rc; > > + } else { > > + devm_remove_action(chip->dev.parent, > > + (void (*)(void *)) tpm_dev_release, > > + &chip->dev); > > This is in the wrong place, the devm should be canceled only if > tpm_chip_register returns success, at that point the caller's contract > is to guarentee a call to tpm_chip_unregister, and > tpm_chip_unregister does the put_device that calls the release > function.
rc == 0 at that point i.e. success. I don't see the problem here.
> Jason
/Jarkko
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