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driver core: Avoid pointless deferred probe attempts

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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 <saravanak@google.com>
Link: https://lore.kernel.org/r/20210302211133.2244281-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Saravana Kannan
2021-03-02 13:11:30 -08:00
committed by Greg Kroah-Hartman
parent 01085e24ff
commit f2db85b64f
2 changed files with 10 additions and 0 deletions
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6
drivers/base/dd.c
View File

@@ -122,6 +122,9 @@ static DECLARE_WORK(deferred_probe_work, deferred_probe_work_func);
void driver_deferred_probe_add(struct device *dev) void driver_deferred_probe_add(struct device *dev)
{ {
if (!dev->can_match)
return;
mutex_lock(&deferred_probe_mutex); mutex_lock(&deferred_probe_mutex);
if (list_empty(&dev->p->deferred_probe)) { if (list_empty(&dev->p->deferred_probe)) {
dev_dbg(dev, "Added to deferred list\n"); dev_dbg(dev, "Added to deferred list\n");
@@ -725,6 +728,7 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev)
if (!device_is_registered(dev)) if (!device_is_registered(dev))
return -ENODEV; return -ENODEV;
dev->can_match = true;
pr_debug("bus: '%s': %s: matched device %s with driver %s\n", pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
drv->bus->name, __func__, dev_name(dev), drv->name); drv->bus->name, __func__, dev_name(dev), drv->name);
@@ -828,6 +832,7 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
return 0; return 0;
} else if (ret == -EPROBE_DEFER) { } else if (ret == -EPROBE_DEFER) {
dev_dbg(dev, "Device match requests probe deferral\n"); dev_dbg(dev, "Device match requests probe deferral\n");
dev->can_match = true;
driver_deferred_probe_add(dev); driver_deferred_probe_add(dev);
} else if (ret < 0) { } else if (ret < 0) {
dev_dbg(dev, "Bus failed to match device: %d\n", ret); dev_dbg(dev, "Bus failed to match device: %d\n", ret);
@@ -1063,6 +1068,7 @@ static int __driver_attach(struct device *dev, void *data)
return 0; return 0;
} else if (ret == -EPROBE_DEFER) { } else if (ret == -EPROBE_DEFER) {
dev_dbg(dev, "Device match requests probe deferral\n"); dev_dbg(dev, "Device match requests probe deferral\n");
dev->can_match = true;
driver_deferred_probe_add(dev); driver_deferred_probe_add(dev);
} else if (ret < 0) { } else if (ret < 0) {
dev_dbg(dev, "Bus failed to match device: %d\n", ret); dev_dbg(dev, "Bus failed to match device: %d\n", ret);

4
include/linux/device.h
View File

@@ -439,6 +439,9 @@ struct dev_links_info {
* @state_synced: The hardware state of this device has been synced to match * @state_synced: The hardware state of this device has been synced to match
* the software state of this device by calling the driver/bus * the software state of this device by calling the driver/bus
* sync_state() callback. * 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 * @dma_coherent: this particular device is dma coherent, even if the
* architecture supports non-coherent devices. * architecture supports non-coherent devices.
* @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
@@ -545,6 +548,7 @@ struct device {
bool offline:1; bool offline:1;
bool of_node_reused:1; bool of_node_reused:1;
bool state_synced:1; bool state_synced:1;
bool can_match:1;
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ #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) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL)