static DEFINE_MUTEX(fwnode_link_lock);
static bool fw_devlink_is_permissive(void);
static bool fw_devlink_drv_reg_done;
+static bool fw_devlink_best_effort;
/**
* fwnode_link_add - Create a link between two fwnode_handles.
}
}
+static bool dev_is_best_effort(struct device *dev)
+{
+ return fw_devlink_best_effort && dev->can_match;
+}
+
/**
* device_links_check_suppliers - Check presence of supplier drivers.
* @dev: Consumer device.
int device_links_check_suppliers(struct device *dev)
{
struct device_link *link;
- int ret = 0;
+ int ret = 0, fwnode_ret = 0;
struct fwnode_handle *sup_fw;
/*
sup_fw = list_first_entry(&dev->fwnode->suppliers,
struct fwnode_link,
c_hook)->supplier;
- dev_err_probe(dev, -EPROBE_DEFER, "wait for supplier %pfwP\n",
- sup_fw);
- mutex_unlock(&fwnode_link_lock);
- return -EPROBE_DEFER;
+ if (!dev_is_best_effort(dev)) {
+ fwnode_ret = -EPROBE_DEFER;
+ dev_err_probe(dev, -EPROBE_DEFER,
+ "wait for supplier %pfwP\n", sup_fw);
+ } else {
+ fwnode_ret = -EAGAIN;
+ }
}
mutex_unlock(&fwnode_link_lock);
+ if (fwnode_ret == -EPROBE_DEFER)
+ return fwnode_ret;
device_links_write_lock();
if (link->status != DL_STATE_AVAILABLE &&
!(link->flags & DL_FLAG_SYNC_STATE_ONLY)) {
+
+ if (dev_is_best_effort(dev) &&
+ link->flags & DL_FLAG_INFERRED &&
+ !link->supplier->can_match) {
+ ret = -EAGAIN;
+ continue;
+ }
+
device_links_missing_supplier(dev);
dev_err_probe(dev, -EPROBE_DEFER,
"supplier %s not ready\n",
dev->links.status = DL_DEV_PROBING;
device_links_write_unlock();
- return ret;
+
+ return ret ? ret : fwnode_ret;
}
/**
* save to drop the managed link completely.
*/
device_link_drop_managed(link);
+ } else if (dev_is_best_effort(dev) &&
+ link->flags & DL_FLAG_INFERRED &&
+ link->status != DL_STATE_CONSUMER_PROBE &&
+ !link->supplier->can_match) {
+ /*
+ * When dev_is_best_effort() is true, we ignore device
+ * links to suppliers that don't have a driver. If the
+ * consumer device still managed to probe, there's no
+ * point in maintaining a device link in a weird state
+ * (consumer probed before supplier). So delete it.
+ */
+ device_link_drop_managed(link);
} else {
WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
WRITE_ONCE(link->status, DL_STATE_ACTIVE);
device_links_write_unlock();
}
+/**
+ * wait_for_init_devices_probe - Try to probe any device needed for init
+ *
+ * Some devices might need to be probed and bound successfully before the kernel
+ * boot sequence can finish and move on to init/userspace. For example, a
+ * network interface might need to be bound to be able to mount a NFS rootfs.
+ *
+ * With fw_devlink=on by default, some of these devices might be blocked from
+ * probing because they are waiting on a optional supplier that doesn't have a
+ * driver. While fw_devlink will eventually identify such devices and unblock
+ * the probing automatically, it might be too late by the time it unblocks the
+ * probing of devices. For example, the IP4 autoconfig might timeout before
+ * fw_devlink unblocks probing of the network interface.
+ *
+ * This function is available to temporarily try and probe all devices that have
+ * a driver even if some of their suppliers haven't been added or don't have
+ * drivers.
+ *
+ * The drivers can then decide which of the suppliers are optional vs mandatory
+ * and probe the device if possible. By the time this function returns, all such
+ * "best effort" probes are guaranteed to be completed. If a device successfully
+ * probes in this mode, we delete all fw_devlink discovered dependencies of that
+ * device where the supplier hasn't yet probed successfully because they have to
+ * be optional dependencies.
+ *
+ * Any devices that didn't successfully probe go back to being treated as if
+ * this function was never called.
+ *
+ * This also means that some devices that aren't needed for init and could have
+ * waited for their optional supplier to probe (when the supplier's module is
+ * loaded later on) would end up probing prematurely with limited functionality.
+ * So call this function only when boot would fail without it.
+ */
+void __init wait_for_init_devices_probe(void)
+{
+ if (!fw_devlink_flags || fw_devlink_is_permissive())
+ return;
+
+ /*
+ * Wait for all ongoing probes to finish so that the "best effort" is
+ * only applied to devices that can't probe otherwise.
+ */
+ wait_for_device_probe();
+
+ pr_info("Trying to probe devices needed for running init ...\n");
+ fw_devlink_best_effort = true;
+ driver_deferred_probe_trigger();
+
+ /*
+ * Wait for all "best effort" probes to finish before going back to
+ * normal enforcement.
+ */
+ wait_for_device_probe();
+ fw_devlink_best_effort = false;
+}
+
static void fw_devlink_unblock_consumers(struct device *dev)
{
struct device_link *link;
* changes in the midst of a probe, then deferred processing should be triggered
* again.
*/
-static void driver_deferred_probe_trigger(void)
+void driver_deferred_probe_trigger(void)
{
if (!driver_deferred_probe_enable)
return;
{
bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
!drv->suppress_bind_attrs;
- int ret;
+ int ret, link_ret;
if (defer_all_probes) {
/*
return -EPROBE_DEFER;
}
- ret = device_links_check_suppliers(dev);
- if (ret)
- return ret;
+ link_ret = device_links_check_suppliers(dev);
+ if (link_ret == -EPROBE_DEFER)
+ return link_ret;
pr_debug("bus: '%s': %s: probing driver %s with device %s\n",
drv->bus->name, __func__, drv->name, dev_name(dev));
ret = call_driver_probe(dev, drv);
if (ret) {
+ /*
+ * If fw_devlink_best_effort is active (denoted by -EAGAIN), the
+ * device might actually probe properly once some of its missing
+ * suppliers have probed. So, treat this as if the driver
+ * returned -EPROBE_DEFER.
+ */
+ if (link_ret == -EAGAIN)
+ ret = -EPROBE_DEFER;
+
/*
* Return probe errors as positive values so that the callers
* can distinguish them from other errors.
projects / kernel.git / commitdiff