by Suzuki K Poulose

[permalink] [raw]

Subject: Re: [PATCH v4 01/13] coresight: Fix loss of connection info when a module is unloaded

On 04/04/2023 14:53, James Clark wrote:
> child_fwnode should be a read only property based on the DT. If it's

minor nit: Not restricted to DT. This also covers the ACPI.

> cleared on the parent device when a child is unloaded, then when the
> child is loaded again the connection won't be remade.
>
> child_dev should be cleared instead which signifies that the connection
> should be remade when the child_fwnode registers a new coresight_device.
>
> Similarly the reference count shouldn't be decremented as long as the
> parent device exists. The correct place to drop the reference is in
> coresight_release_platform_data() which is already done.
>
> Reproducible on Juno with the following steps:
>
> # load all coresight modules.
> $ cd /sys/bus/coresight/devices/
> $ echo 1 > tmc_etr0/enable_sink
> $ echo 1 > etm0/enable_source
> # Works fine ^
>
> $ echo 0 > etm0/enable_source
> $ rmmod coresight-funnel
> $ modprobe coresight-funnel
> $ echo 1 > etm0/enable_source
> -bash: echo: write error: Invalid argument
>
> Fixes: 37ea1ffddffa ("coresight: Use fwnode handle instead of device names")
> Fixes: 2af89ebacf29 ("coresight: Clear the connection field properly")
> Signed-off-by: James Clark <[email protected]>

Looks good to me.

Tested-by: Suzuki K Poulose <[email protected]>

2023-04-04 14:24:17

by Suzuki K Poulose

[permalink] [raw]

Subject: Re: [PATCH v4 07/13] coresight: Store pointers to connections rather than an array of them

On 04/04/2023 14:53, James Clark wrote:
> This will allow the same connection object to be referenced via the
> input connection list in a later commit rather than duplicating them.
>
> Signed-off-by: James Clark <[email protected]>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 47 ++++++++++---------
> .../hwtracing/coresight/coresight-platform.c | 10 ++--
> drivers/hwtracing/coresight/coresight-priv.h | 1 +
> .../hwtracing/coresight/coresight-tmc-etr.c | 2 +-
> include/linux/coresight.h | 5 +-
> 5 files changed, 35 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 91274e7e6944..0b738960973b 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -119,7 +119,7 @@ static int coresight_find_link_inport(struct coresight_device *csdev,
> struct coresight_connection *conn;
>
> for (i = 0; i < parent->pdata->nr_outconns; i++) {
> - conn = &parent->pdata->out_conns[i];
> + conn = parent->pdata->out_conns[i];
> if (conn->dest_dev == csdev)
> return conn->dest_port;
> }
> @@ -137,7 +137,7 @@ static int coresight_find_link_outport(struct coresight_device *csdev,
> struct coresight_connection *conn;
>
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> - conn = &csdev->pdata->out_conns[i];
> + conn = csdev->pdata->out_conns[i];
> if (conn->dest_dev == child)
> return conn->src_port;
> }
> @@ -606,7 +606,7 @@ coresight_find_enabled_sink(struct coresight_device *csdev)
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> struct coresight_device *child_dev;
>
> - child_dev = csdev->pdata->out_conns[i].dest_dev;
> + child_dev = csdev->pdata->out_conns[i]->dest_dev;
> if (child_dev)
> sink = coresight_find_enabled_sink(child_dev);
> if (sink)
> @@ -722,7 +722,7 @@ static int coresight_grab_device(struct coresight_device *csdev)
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> struct coresight_device *child;
>
> - child = csdev->pdata->out_conns[i].dest_dev;
> + child = csdev->pdata->out_conns[i]->dest_dev;
> if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
> if (!coresight_get_ref(child))
> goto err;
> @@ -733,7 +733,7 @@ static int coresight_grab_device(struct coresight_device *csdev)
> for (i--; i >= 0; i--) {
> struct coresight_device *child;
>
> - child = csdev->pdata->out_conns[i].dest_dev;
> + child = csdev->pdata->out_conns[i]->dest_dev;
> if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
> coresight_put_ref(child);
> }
> @@ -752,7 +752,7 @@ static void coresight_drop_device(struct coresight_device *csdev)
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> struct coresight_device *child;
>
> - child = csdev->pdata->out_conns[i].dest_dev;
> + child = csdev->pdata->out_conns[i]->dest_dev;
> if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
> coresight_put_ref(child);
> }
> @@ -794,7 +794,7 @@ static int _coresight_build_path(struct coresight_device *csdev,
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> struct coresight_device *child_dev;
>
> - child_dev = csdev->pdata->out_conns[i].dest_dev;
> + child_dev = csdev->pdata->out_conns[i]->dest_dev;
> if (child_dev &&
> _coresight_build_path(child_dev, sink, path) == 0) {
> found = true;
> @@ -964,7 +964,7 @@ coresight_find_sink(struct coresight_device *csdev, int *depth)
> struct coresight_device *child_dev, *sink = NULL;
> int child_depth = curr_depth;
>
> - child_dev = csdev->pdata->out_conns[i].dest_dev;
> + child_dev = csdev->pdata->out_conns[i]->dest_dev;
> if (child_dev)
> sink = coresight_find_sink(child_dev, &child_depth);
>
> @@ -1334,7 +1334,7 @@ static int coresight_orphan_match(struct device *dev, void *data)
> * an orphan connection whose name matches @csdev, link it.
> */
> for (i = 0; i < i_csdev->pdata->nr_outconns; i++) {
> - conn = &i_csdev->pdata->out_conns[i];
> + conn = i_csdev->pdata->out_conns[i];
>
> /* We have found at least one orphan connection */
> if (conn->dest_dev == NULL) {
> @@ -1372,7 +1372,7 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev)
> int i, ret = 0;
>
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> - struct coresight_connection *conn = &csdev->pdata->out_conns[i];
> + struct coresight_connection *conn = csdev->pdata->out_conns[i];
>
> conn->dest_dev =
> coresight_find_csdev_by_fwnode(conn->dest_fwnode);
> @@ -1406,15 +1406,12 @@ static int coresight_remove_match(struct device *dev, void *data)
> * a connection whose name matches @csdev, remove it.
> */
> for (i = 0; i < iterator->pdata->nr_outconns; i++) {
> - conn = &iterator->pdata->out_conns[i];
> + conn = iterator->pdata->out_conns[i];
>
> - if (conn->dest_dev == NULL)
> - continue;
> -
> - if (csdev->dev.fwnode == conn->dest_fwnode) {
> + /* Child_dev being set signifies that the links were made */
> + if (csdev->dev.fwnode == conn->dest_fwnode && conn->dest_dev) {
> iterator->orphan = true;
> coresight_remove_links(iterator, conn);
> -
> conn->dest_dev = NULL;
> /* No need to continue */
> break;
> @@ -1534,22 +1531,26 @@ void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
> * to the output port of this device.
> */
> void coresight_release_platform_data(struct coresight_device *csdev,
> + struct device *dev,
> struct coresight_platform_data *pdata)
> {
> int i;
> - struct coresight_connection *conns = pdata->out_conns;
> + struct coresight_connection **conns = pdata->out_conns;
>
> for (i = 0; i < pdata->nr_outconns; i++) {
> /* If we have made the links, remove them now */
> - if (csdev && conns[i].dest_dev)
> - coresight_remove_links(csdev, &conns[i]);
> + if (csdev && conns[i]->dest_dev)
> + coresight_remove_links(csdev, conns[i]);
> /*
> * Drop the refcount and clear the handle as this device
> * is going away
> */
> - fwnode_handle_put(conns[i].dest_fwnode);
> - conns[i].dest_fwnode = NULL;
> + fwnode_handle_put(conns[i]->dest_fwnode);
> + conns[i]->dest_fwnode = NULL;
> + devm_kfree(dev, conns[i]);
> }
> + devm_kfree(dev, pdata->out_conns);
> + devm_kfree(dev, pdata);
> if (csdev)
> coresight_remove_conns_sysfs_group(csdev);
> }
> @@ -1666,7 +1667,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
>
> err_out:
> /* Cleanup the connection information */
> - coresight_release_platform_data(NULL, desc->pdata);
> + coresight_release_platform_data(NULL, desc->dev, desc->pdata);
> return ERR_PTR(ret);
> }
> EXPORT_SYMBOL_GPL(coresight_register);
> @@ -1679,7 +1680,7 @@ void coresight_unregister(struct coresight_device *csdev)
> cti_assoc_ops->remove(csdev);
> coresight_remove_conns(csdev);
> coresight_clear_default_sink(csdev);
> - coresight_release_platform_data(csdev, csdev->pdata);
> + coresight_release_platform_data(csdev, csdev->dev.parent, csdev->pdata);
> device_unregister(&csdev->dev);
> }
> EXPORT_SYMBOL_GPL(coresight_unregister);
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 8c2029336161..017ea5762988 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -37,7 +37,7 @@ coresight_add_out_conn(struct device *dev,
> * Warn on any existing duplicate output port.
> */
> for (i = 0; i < pdata->nr_outconns; ++i) {
> - conn = &pdata->out_conns[i];
> + conn = pdata->out_conns[i];
> /* Output == -1 means ignore the port for example for helpers */
> if (conn->src_port != -1 &&
> conn->src_port == new_conn->src_port) {
> @@ -54,8 +54,10 @@ coresight_add_out_conn(struct device *dev,
> if (!pdata->out_conns)
> return ERR_PTR(-ENOMEM);
>
> - pdata->out_conns[pdata->nr_outconns - 1] = *new_conn;
> - return &pdata->out_conns[pdata->nr_outconns - 1];
> + pdata->out_conns[pdata->nr_outconns - 1] = devm_kmalloc(
> + dev, sizeof(struct coresight_connection), GFP_KERNEL);

Please check the error in allocation. While at it, please use a variable
to simplify the code reading.

Otherwise looks good to me

Suzuki