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Date: Wed, 5 Jan 2022 09:05:21 +0100
From: Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>
CC: Bjorn Andersson <bjorn.andersson@...aro.org>,
<linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-stm32@...md-mailman.stormreply.com>
Subject: Re: [RFC PATCH v2 1/6] remoteproc: core: Introduce virtio device
add/remove functions
Hello Mathieu,
On 1/4/22 8:08 PM, Mathieu Poirier wrote:
> Good morning,
>
> On Wed, Dec 22, 2021 at 09:23:44AM +0100, Arnaud Pouliquen wrote:
>> In preparation of the migration of the management of rvdev in
>> remoteproc_virtio.c, this patch spins off new functions to manage the
>> remoteproc virtio device.
>>
>> The rproc_rvdev_add_device and rproc_rvdev_remove_device will be
>> moved to remoteproc_virtio.c.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
>> ---
>> update vs previous revision:
>> - update according to the rebase from v15-rc1 to v16-rc1
>> - split patch to introduce rproc_register_rvdev and rproc_unregister_rvdev
>> function in a separate patch
>> ---
>> drivers/remoteproc/remoteproc_core.c | 94 +++++++++++++++++-----------
>> 1 file changed, 57 insertions(+), 37 deletions(-)
>>
>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>> index 69f51acf235e..d1f1c5c25bd7 100644
>> --- a/drivers/remoteproc/remoteproc_core.c
>> +++ b/drivers/remoteproc/remoteproc_core.c
>> @@ -484,6 +484,61 @@ static int copy_dma_range_map(struct device *to, struct device *from)
>> return 0;
>> }
>>
>> +static int rproc_rvdev_add_device(struct rproc_vdev *rvdev)
>> +{
>> + struct rproc *rproc = rvdev->rproc;
>> + char name[16];
>> + int ret;
>> +
>> + snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
>> + rvdev->dev.parent = &rproc->dev;
>> + rvdev->dev.release = rproc_rvdev_release;
>> + dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
>> + dev_set_drvdata(&rvdev->dev, rvdev);
>> +
>> + ret = device_register(&rvdev->dev);
>> + if (ret) {
>> + put_device(&rvdev->dev);
>> + return ret;
>> + }
>
> Registering the device here is a problem... If device_register() fails
> put_device() is called and we return, only to call device_unregister() on the
> same device in rproc_handle_vdev().
>
> Moreover in rproc_handle_vdev(), device_unregister() is called in the error
> path but device_register() is called here in rproc_rvdev_add_device(). This
> introduces coupling between the two functions, making it hard to maintain from
> hereon.
Very relevant, I need to rework the error management.
>
> I suggest calling device_register() in rproc_handle_vdev() after
> rproc_rvdev_add_device() has returned successfully.
One of the goals of this patchset is to move the device_register in
remote_proc_virtio.c
Doing this would not go in this direction.
I need to test but following could be an alternative:
- Call rproc_rvdev_remove_device in rproc_handle_vdev in case of error.
- Remove the put_device in rproc_rvdev_add_device.
=> This would be aligned with patch [6/6] implementation
with rproc_virtio_register_device/rproc_virtio_unregister_device...
Thanks,
Arnaud
>
> More comments to come tomorrow.
>
> Thanks,
> Mathieu
>
>> + ret = copy_dma_range_map(&rvdev->dev, rproc->dev.parent);
>> + if (ret)
>> + goto free_rvdev;
>> +
>> + /* Make device dma capable by inheriting from parent's capabilities */
>> + set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
>> +
>> + ret = dma_coerce_mask_and_coherent(&rvdev->dev,
>> + dma_get_mask(rproc->dev.parent));
>> + if (ret) {
>> + dev_warn(&rvdev->dev,
>> + "Failed to set DMA mask %llx. Trying to continue... (%pe)\n",
>> + dma_get_mask(rproc->dev.parent), ERR_PTR(ret));
>> + }
>> +
>> + list_add_tail(&rvdev->node, &rproc->rvdevs);
>> +
>> + rvdev->subdev.start = rproc_vdev_do_start;
>> + rvdev->subdev.stop = rproc_vdev_do_stop;
>> +
>> + rproc_add_subdev(rproc, &rvdev->subdev);
>> +
>> + return 0;
>> +
>> +free_rvdev:
>> + device_unregister(&rvdev->dev);
>> + return ret;
>> +}
>> +
>> +static void rproc_rvdev_remove_device(struct rproc_vdev *rvdev)
>> +{
>> + struct rproc *rproc = rvdev->rproc;
>> +
>> + rproc_remove_subdev(rproc, &rvdev->subdev);
>> + list_del(&rvdev->node);
>> + device_unregister(&rvdev->dev);
>> +}
>> +
>> /**
>> * rproc_handle_vdev() - handle a vdev fw resource
>> * @rproc: the remote processor
>> @@ -519,7 +574,6 @@ static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
>> struct device *dev = &rproc->dev;
>> struct rproc_vdev *rvdev;
>> int i, ret;
>> - char name[16];
>>
>> /* make sure resource isn't truncated */
>> if (struct_size(rsc, vring, rsc->num_of_vrings) + rsc->config_len >
>> @@ -553,34 +607,10 @@ static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
>> rvdev->rproc = rproc;
>> rvdev->index = rproc->nb_vdev++;
>>
>> - /* Initialise vdev subdevice */
>> - snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
>> - rvdev->dev.parent = &rproc->dev;
>> - rvdev->dev.release = rproc_rvdev_release;
>> - dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
>> - dev_set_drvdata(&rvdev->dev, rvdev);
>> -
>> - ret = device_register(&rvdev->dev);
>> - if (ret) {
>> - put_device(&rvdev->dev);
>> - return ret;
>> - }
>> -
>> - ret = copy_dma_range_map(&rvdev->dev, rproc->dev.parent);
>> + ret = rproc_rvdev_add_device(rvdev);
>> if (ret)
>> goto free_rvdev;
>>
>> - /* Make device dma capable by inheriting from parent's capabilities */
>> - set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
>> -
>> - ret = dma_coerce_mask_and_coherent(&rvdev->dev,
>> - dma_get_mask(rproc->dev.parent));
>> - if (ret) {
>> - dev_warn(dev,
>> - "Failed to set DMA mask %llx. Trying to continue... (%pe)\n",
>> - dma_get_mask(rproc->dev.parent), ERR_PTR(ret));
>> - }
>> -
>> /* parse the vrings */
>> for (i = 0; i < rsc->num_of_vrings; i++) {
>> ret = rproc_parse_vring(rvdev, rsc, i);
>> @@ -598,13 +628,6 @@ static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
>> goto unwind_vring_allocations;
>> }
>>
>> - list_add_tail(&rvdev->node, &rproc->rvdevs);
>> -
>> - rvdev->subdev.start = rproc_vdev_do_start;
>> - rvdev->subdev.stop = rproc_vdev_do_stop;
>> -
>> - rproc_add_subdev(rproc, &rvdev->subdev);
>> -
>> return 0;
>>
>> unwind_vring_allocations:
>> @@ -619,7 +642,6 @@ void rproc_vdev_release(struct kref *ref)
>> {
>> struct rproc_vdev *rvdev = container_of(ref, struct rproc_vdev, refcount);
>> struct rproc_vring *rvring;
>> - struct rproc *rproc = rvdev->rproc;
>> int id;
>>
>> for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
>> @@ -627,9 +649,7 @@ void rproc_vdev_release(struct kref *ref)
>> rproc_free_vring(rvring);
>> }
>>
>> - rproc_remove_subdev(rproc, &rvdev->subdev);
>> - list_del(&rvdev->node);
>> - device_unregister(&rvdev->dev);
>> + rproc_rvdev_remove_device(rvdev);
>> }
>>
>> /**
>> --
>> 2.17.1
>>
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