On Thu, 26 Jul 2018 21:54:17 +0200
Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:
> +/**
> + * assign_adapter_store
> + *
> + * @dev: the matrix device
> + * @attr: a mediated matrix device attribute
> + * @buf: a buffer containing the adapter ID (APID) to be assigned
> + * @count: the number of bytes in @buf
> + *
> + * Parses the APID from @buf and assigns it to the mediated matrix device.
> + *
> + * Returns the number of bytes processed if the APID is valid; otherwise returns
> + * an error.
> + */
> +static ssize_t assign_adapter_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + int ret;
> + unsigned long apid;
> + struct mdev_device *mdev = mdev_from_dev(dev);
> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> + unsigned long max_apid = matrix_mdev->matrix.apm_max;
> +
> + ret = kstrtoul(buf, 0, &apid);
> + if (ret || (apid > max_apid)) {
> + pr_warn("%s: %s: adapter id '%s' not a value from 0 to %02lu(%#04lx)\n",
> + VFIO_AP_MODULE_NAME, __func__, buf, max_apid, max_apid);
I'm not sure how helpful a message to the syslog is if you are writing
to sysfs attributes. If you decide to drop the message, you could do
if (apid > max_apid)
ret = -EINVAL;
if (ret)
return ret;
which looks more straightforward to me.
> +
> + if (!ret)
> + ret = -EINVAL;
> +
> + return ret;
> + }
> +
> + /* Set the bit in the AP mask (APM) corresponding to the AP adapter
> + * number (APID). The bits in the mask, from most significant to least
> + * significant bit, correspond to APIDs 0-255.
> + */
> + mutex_lock(&matrix_dev.lock);
> + set_bit_inv(apid, matrix_mdev->matrix.apm);
> + ret = count;
> +
> + mutex_unlock(&matrix_dev.lock);
> +
> + return ret;
> +}
> +static DEVICE_ATTR_WO(assign_adapter);
> +
> +/**
> + * unassign_adapter_store
> + *
> + * @dev: the matrix device
> + * @attr: a mediated matrix device attribute
> + * @buf: a buffer containing the adapter ID (APID) to be assigned
> + * @count: the number of bytes in @buf
> + *
> + * Parses the APID from @buf and unassigns it from the mediated matrix device.
> + * The APID must be a valid value
> + *
> + * Returns the number of bytes processed if the APID is valid; otherwise returns
> + * an error.
> + */
> +static ssize_t unassign_adapter_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + int ret;
> + unsigned long apid;
> + struct mdev_device *mdev = mdev_from_dev(dev);
> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
> +
> + unsigned long max_apid = matrix_mdev->matrix.apm_max;
> +
> + ret = kstrtoul(buf, 0, &apid);
> + if (ret || (apid > max_apid)) {
> + pr_warn("%s: %s: adapter id '%s' must be a value from 0 to %02lu(%#04lx)\n",
> + VFIO_AP_MODULE_NAME, __func__, buf, max_apid, max_apid);
dito
> +
> + if (!ret)
> + ret = -EINVAL;
> +
> + return ret;
> + }
> +
> + mutex_lock(&matrix_dev.lock);
> + if (!test_bit_inv(apid, matrix_mdev->matrix.apm)) {
> + pr_warn("%s: %s: adapter id %02lu(%#04lx) not assigned\n",
> + VFIO_AP_MODULE_NAME, __func__, apid, apid);
> + ret = -ENODEV;
Any reason why this needs to be an error? Setting a bit that was set
before is not an error, either.
> + goto done;
> + }
> +
> + clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm);
> + ret = count;
> +
> +done:
> + mutex_unlock(&matrix_dev.lock);
> +
> + return ret;
> +}
> +DEVICE_ATTR_WO(unassign_adapter);
