Messages in this thread | | | Subject | Re: [PATCH v9 10/22] s390: vfio-ap: sysfs interfaces to configure adapters | From | Tony Krowiak <> | Date | Wed, 15 Aug 2018 12:59:35 -0400 |
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On 08/15/2018 05:52 AM, Cornelia Huck wrote: > On Mon, 13 Aug 2018 17:48:07 -0400 > Tony Krowiak <akrowiak@linux.vnet.ibm.com> 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 = 0; > You don't need to initialize this to 0, as kstrtoul will set it in any > case.
Right you are! Will change it.
> >> + 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) >> + return ret; >> + if (apid > max_apid) >> + return -EINVAL; >> + >> + /* 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); >> + >> + ret = vfio_ap_mdev_verify_queues_reserved_for_apid(matrix_mdev, apid); > That function name really is a mouthful :) I don't have any better > suggestions, though.
It is, but I think it describes exactly what the function does.
> >> + if (ret) >> + goto done; >> + >> + set_bit_inv(apid, matrix_mdev->matrix.apm); >> + >> + ret = vfio_ap_mdev_verify_no_sharing(matrix_mdev); >> + if (ret) >> + goto share_err; >> + >> + ret = count; >> + goto done; >> + >> +share_err: >> + clear_bit_inv(apid, matrix_mdev->matrix.apm); >> +done: >> + 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 > A valid value, but not necessarily assigned, right?
You are correct, if the APID is not assigned, then the corresponding bit will be cleared regardless. In a previous version, the functions failed if the APID is not assigned, but a colleague removed that check. I guess it makes sense given it really does not hurt anything to ask to unassign an APID that isn't assigned to begin with. Would you prefer I update the comment, or do you feel the user should be made aware of an attempt to unassign an APID that is not assigned?
> >> + * >> + * 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); >> + >> + ret = kstrtoul(buf, 0, &apid); >> + if (ret) >> + return ret; >> + >> + if (apid > matrix_mdev->matrix.apm_max) >> + return -EINVAL; >> + >> + mutex_lock(&matrix_dev.lock); >> + clear_bit_inv((unsigned long)apid, matrix_mdev->matrix.apm); >> + mutex_unlock(&matrix_dev.lock); >> + >> + return count; >> +} >> +DEVICE_ATTR_WO(unassign_adapter); > In general, looks good to me.
That is good news indeed.
>
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