diff options
| -rw-r--r-- | drivers/base/base.h | 1 | ||||
| -rw-r--r-- | drivers/base/core.c | 100 | ||||
| -rw-r--r-- | drivers/base/dd.c | 19 | ||||
| -rw-r--r-- | include/linux/device/driver.h | 1 |
4 files changed, 110 insertions, 11 deletions
diff --git a/drivers/base/base.h b/drivers/base/base.h index ab71403d102f..b3a43a164dcd 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -160,6 +160,7 @@ extern int devres_release_all(struct device *dev); extern void device_block_probing(void); extern void device_unblock_probing(void); extern void deferred_probe_extend_timeout(void); +extern void driver_deferred_probe_trigger(void); /* /sys/devices directory */ extern struct kset *devices_kset; diff --git a/drivers/base/core.c b/drivers/base/core.c index 7cd789c4985d..61fdfe99b348 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -54,6 +54,7 @@ static unsigned int defer_sync_state_count = 1; 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. @@ -965,6 +966,11 @@ static void device_links_missing_supplier(struct device *dev) } } +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. @@ -984,7 +990,7 @@ static void device_links_missing_supplier(struct device *dev) 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; /* @@ -997,12 +1003,17 @@ int device_links_check_suppliers(struct device *dev) 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(); @@ -1012,6 +1023,14 @@ int device_links_check_suppliers(struct device *dev) 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", @@ -1024,7 +1043,8 @@ int device_links_check_suppliers(struct device *dev) dev->links.status = DL_DEV_PROBING; device_links_write_unlock(); - return ret; + + return ret ? ret : fwnode_ret; } /** @@ -1289,6 +1309,18 @@ void device_links_driver_bound(struct device *dev) * 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); @@ -1655,6 +1687,62 @@ void fw_devlink_drivers_done(void) 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; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 11b0fb6414d3..4a55fbb7e0da 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -172,7 +172,7 @@ static bool driver_deferred_probe_enable; * 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; @@ -580,7 +580,7 @@ static int really_probe(struct device *dev, struct device_driver *drv) { bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) && !drv->suppress_bind_attrs; - int ret; + int ret, link_ret; if (defer_all_probes) { /* @@ -592,9 +592,9 @@ static int really_probe(struct device *dev, struct device_driver *drv) 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)); @@ -634,6 +634,15 @@ re_probe: 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. */ diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index 700453017e1c..2114d65b862f 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -129,6 +129,7 @@ extern struct device_driver *driver_find(const char *name, struct bus_type *bus); extern int driver_probe_done(void); extern void wait_for_device_probe(void); +void __init wait_for_init_devices_probe(void); /* sysfs interface for exporting driver attributes */ |