Re: [PATCH v1 1/3] driver core: Avoid pointless deferred probe attempts
On Tue, Mar 09, 2021 at 03:26:05PM -0800, Saravana Kannan wrote: > On Tue, Mar 2, 2021 at 1:11 PM Saravana Kannan wrote: > > > > There's no point in adding a device to the deferred probe list if we > > know for sure that it doesn't have a matching driver. So, check if a > > device can match with a driver before adding it to the deferred probe > > list. > > > > Signed-off-by: Saravana Kannan > > Rafael/Greg, > > Any concerns with this specific patch? Do you see any bugs? I'm asking > because some of the other improvements I'm working on depend on this > flag. So I want to make sure this can land before I take my work in > progress too far. Looks fine, now queuing up, thanks. greg k-h
Re: [PATCH v1 1/3] driver core: Avoid pointless deferred probe attempts
On Tue, Mar 2, 2021 at 1:11 PM Saravana Kannan wrote:
>
> There's no point in adding a device to the deferred probe list if we
> know for sure that it doesn't have a matching driver. So, check if a
> device can match with a driver before adding it to the deferred probe
> list.
>
> Signed-off-by: Saravana Kannan
Rafael/Greg,
Any concerns with this specific patch? Do you see any bugs? I'm asking
because some of the other improvements I'm working on depend on this
flag. So I want to make sure this can land before I take my work in
progress too far.
-Saravana
> ---
> drivers/base/dd.c | 6 ++
> include/linux/device.h | 4
> 2 files changed, 10 insertions(+)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 9179825ff646..f18963f42e21 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work,
> deferred_probe_work_func);
>
> void driver_deferred_probe_add(struct device *dev)
> {
> + if (!dev->can_match)
> + return;
> +
> mutex_lock(&deferred_probe_mutex);
> if (list_empty(&dev->p->deferred_probe)) {
> dev_dbg(dev, "Added to deferred list\n");
> @@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver *drv,
> struct device *dev)
> if (!device_is_registered(dev))
> return -ENODEV;
>
> + dev->can_match = true;
> pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
> drv->bus->name, __func__, dev_name(dev), drv->name);
>
> @@ -829,6 +833,7 @@ static int __device_attach_driver(struct device_driver
> *drv, void *_data)
> return 0;
> } else if (ret == -EPROBE_DEFER) {
> dev_dbg(dev, "Device match requests probe deferral\n");
> + dev->can_match = true;
> driver_deferred_probe_add(dev);
> } else if (ret < 0) {
> dev_dbg(dev, "Bus failed to match device: %d\n", ret);
> @@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void
> *data)
> return 0;
> } else if (ret == -EPROBE_DEFER) {
> dev_dbg(dev, "Device match requests probe deferral\n");
> + dev->can_match = true;
> driver_deferred_probe_add(dev);
> } else if (ret < 0) {
> dev_dbg(dev, "Bus failed to match device: %d\n", ret);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index ba660731bd25..569932d282c0 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -439,6 +439,9 @@ struct dev_links_info {
> * @state_synced: The hardware state of this device has been synced to match
> * the software state of this device by calling the driver/bus
> * sync_state() callback.
> + * @can_match: The device has matched with a driver at least once or it is in
> + * a bus (like AMBA) which can't check for matching drivers until
> + * other devices probe successfully.
> * @dma_coherent: this particular device is dma coherent, even if the
> * architecture supports non-coherent devices.
> * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
> @@ -545,6 +548,7 @@ struct device {
> booloffline:1;
> boolof_node_reused:1;
> boolstate_synced:1;
> + boolcan_match:1;
> #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
> defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
> defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
> --
> 2.30.1.766.gb4fecdf3b7-goog
>
[PATCH v1 1/3] driver core: Avoid pointless deferred probe attempts
There's no point in adding a device to the deferred probe list if we
know for sure that it doesn't have a matching driver. So, check if a
device can match with a driver before adding it to the deferred probe
list.
Signed-off-by: Saravana Kannan
---
drivers/base/dd.c | 6 ++
include/linux/device.h | 4
2 files changed, 10 insertions(+)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 9179825ff646..f18963f42e21 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -123,6 +123,9 @@ static DECLARE_WORK(deferred_probe_work,
deferred_probe_work_func);
void driver_deferred_probe_add(struct device *dev)
{
+ if (!dev->can_match)
+ return;
+
mutex_lock(&deferred_probe_mutex);
if (list_empty(&dev->p->deferred_probe)) {
dev_dbg(dev, "Added to deferred list\n");
@@ -726,6 +729,7 @@ static int driver_probe_device(struct device_driver *drv,
struct device *dev)
if (!device_is_registered(dev))
return -ENODEV;
+ dev->can_match = true;
pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
drv->bus->name, __func__, dev_name(dev), drv->name);
@@ -829,6 +833,7 @@ static int __device_attach_driver(struct device_driver
*drv, void *_data)
return 0;
} else if (ret == -EPROBE_DEFER) {
dev_dbg(dev, "Device match requests probe deferral\n");
+ dev->can_match = true;
driver_deferred_probe_add(dev);
} else if (ret < 0) {
dev_dbg(dev, "Bus failed to match device: %d\n", ret);
@@ -1064,6 +1069,7 @@ static int __driver_attach(struct device *dev, void *data)
return 0;
} else if (ret == -EPROBE_DEFER) {
dev_dbg(dev, "Device match requests probe deferral\n");
+ dev->can_match = true;
driver_deferred_probe_add(dev);
} else if (ret < 0) {
dev_dbg(dev, "Bus failed to match device: %d\n", ret);
diff --git a/include/linux/device.h b/include/linux/device.h
index ba660731bd25..569932d282c0 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -439,6 +439,9 @@ struct dev_links_info {
* @state_synced: The hardware state of this device has been synced to match
* the software state of this device by calling the driver/bus
* sync_state() callback.
+ * @can_match: The device has matched with a driver at least once or it is in
+ * a bus (like AMBA) which can't check for matching drivers until
+ * other devices probe successfully.
* @dma_coherent: this particular device is dma coherent, even if the
* architecture supports non-coherent devices.
* @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
@@ -545,6 +548,7 @@ struct device {
booloffline:1;
boolof_node_reused:1;
boolstate_synced:1;
+ boolcan_match:1;
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)
--
2.30.1.766.gb4fecdf3b7-goog
