Re: [RFC PATCH v2 1/6] remoteproc: core: Introduce virtio device add/remove functions
From: Arnaud POULIQUEN
Date: Wed Jan 05 2022 - 03:05:29 EST
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@xxxxxxxxxxx>
---
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