Re: [PATCH v5 4/5] Initialize TPM and get durations and timeouts

["Stefan Berger" <stefanb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

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Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> wrote on 02/11/2016 
01:12:08 PM:


> 
> On Thu, Feb 11, 2016 at 10:24:18AM -0500, Stefan Berger wrote:
> >    We need two steps here. One to let tpmm_chip_alloc call two 
functions
> >    tpm_chip_alloc + tpmm_chip_dev (better name?), which are both going 
to
> >    be public and called by tpm-vtpm.c, and provide tpm_chip_free. Let 
me
> >    do that. Then we can get rid of the bitmap for the chip->dev_num
> >    independently and use idr there.
> 
> Make sense. Don't change the names all the drivers would have to be
> churn'd. tpm_chip_alloc, tpmm_chip_alloc.
> 

That's right:

struct tpm_chip *tpmm_chip_alloc(struct device *dev,
                                 const struct tpm_class_ops *ops)
{
        struct tpm_chip *chip;

        chip = tpm_chip_alloc(ops);
        if (IS_ERR(chip))
                return chip;

        tpmm_chip_dev(chip, dev);

        return chip;
}
EXPORT_SYMBOL_GPL(tpmm_chip_alloc);


> It is probably OK just to use put_device(&chip->dev), tpm_chip_put is
> already taken for something else. Don't call it free, it isn't free.

tpm_chip_free undoes what tpm_chip_alloc did.

/**
 * tpm_chip_alloc() - allocate a new struct tpm_chip instance
 * @dev: device to which the chip is associated
 * @ops: struct tpm_class_ops instance
 *
 * Allocates a new struct tpm_chip instance and assigns a free
 * device number for it.
 */
struct tpm_chip *tpm_chip_alloc(const struct tpm_class_ops *ops)
{
        struct tpm_chip *chip;

        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (chip == NULL)
                return ERR_PTR(-ENOMEM);

        mutex_init(&chip->tpm_mutex);
        INIT_LIST_HEAD(&chip->list);

        chip->ops = ops;

        spin_lock(&driver_lock);
        chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES);
        if (chip->dev_num < TPM_NUM_DEVICES)
                set_bit(chip->dev_num, dev_mask);
        spin_unlock(&driver_lock);

        if (chip->dev_num >= TPM_NUM_DEVICES) {
                pr_err("No available tpm device numbers\n");
                kfree(chip);
                return ERR_PTR(-ENOMEM);
        }

        scnprintf(chip->devname, sizeof(chip->devname), "tpm%d", 
chip->dev_num);

        return chip;
}
EXPORT_SYMBOL_GPL(tpm_chip_alloc);

/**
 * tpm_chip_free() - free tpm_chip previously allocated with 
tpm_chip_alloc
 * @chip: the tpm_chip to free
 */
void tpm_chip_free(struct tpm_chip *chip)
{
        spin_lock(&driver_lock);
        clear_bit(chip->dev_num, dev_mask);
        spin_unlock(&driver_lock);

        kfree(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_free);


Good?

   Stefan

> 
> Jason
> 


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