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| author | Alex Shi <alex.shi@linaro.org> | 2014-06-09 12:55:42 +0800 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2014-06-09 12:55:42 +0800 |
| commit | 3b8d7f4db34913c8e2ea0177723784b646f7424e (patch) | |
| tree | 1c28a8a8c273dffd031935f5ee509db5c5e0f386 /drivers/base | |
| parent | f669f023e2ce45ab6e289bd980d435e1dae0e362 (diff) | |
| parent | c2f7eb8029e23c4f5445340d8fc0d05367538e6d (diff) | |
Merge tag v3.10.42 into linux-linaro-lsk
This is the 3.10.42 stable release
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/dd.c | 17 | ||||
| -rw-r--r-- | drivers/base/topology.c | 3 |
2 files changed, 18 insertions, 2 deletions
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 06051767393f..8a8d611f2021 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -52,6 +52,7 @@ static DEFINE_MUTEX(deferred_probe_mutex); static LIST_HEAD(deferred_probe_pending_list); static LIST_HEAD(deferred_probe_active_list); static struct workqueue_struct *deferred_wq; +static atomic_t deferred_trigger_count = ATOMIC_INIT(0); /** * deferred_probe_work_func() - Retry probing devices in the active list. @@ -135,6 +136,17 @@ static bool driver_deferred_probe_enable = false; * This functions moves all devices from the pending list to the active * list and schedules the deferred probe workqueue to process them. It * should be called anytime a driver is successfully bound to a device. + * + * Note, there is a race condition in multi-threaded probe. In the case where + * more than one device is probing at the same time, it is possible for one + * probe to complete successfully while another is about to defer. If the second + * depends on the first, then it will get put on the pending list after the + * trigger event has already occured and will be stuck there. + * + * The atomic 'deferred_trigger_count' is used to determine if a successful + * trigger has occurred in the midst of probing a driver. If the trigger count + * changes in the midst of a probe, then deferred processing should be triggered + * again. */ static void driver_deferred_probe_trigger(void) { @@ -147,6 +159,7 @@ static void driver_deferred_probe_trigger(void) * into the active list so they can be retried by the workqueue */ mutex_lock(&deferred_probe_mutex); + atomic_inc(&deferred_trigger_count); list_splice_tail_init(&deferred_probe_pending_list, &deferred_probe_active_list); mutex_unlock(&deferred_probe_mutex); @@ -265,6 +278,7 @@ static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue); static int really_probe(struct device *dev, struct device_driver *drv) { int ret = 0; + int local_trigger_count = atomic_read(&deferred_trigger_count); atomic_inc(&probe_count); pr_debug("bus: '%s': %s: probing driver %s with device %s\n", @@ -310,6 +324,9 @@ probe_failed: /* Driver requested deferred probing */ dev_info(dev, "Driver %s requests probe deferral\n", drv->name); driver_deferred_probe_add(dev); + /* Did a trigger occur while probing? Need to re-trigger if yes */ + if (local_trigger_count != atomic_read(&deferred_trigger_count)) + driver_deferred_probe_trigger(); } else if (ret != -ENODEV && ret != -ENXIO) { /* driver matched but the probe failed */ printk(KERN_WARNING diff --git a/drivers/base/topology.c b/drivers/base/topology.c index ae989c57cd5e..bcd19886fa1a 100644 --- a/drivers/base/topology.c +++ b/drivers/base/topology.c @@ -40,8 +40,7 @@ static ssize_t show_##name(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ - unsigned int cpu = dev->id; \ - return sprintf(buf, "%d\n", topology_##name(cpu)); \ + return sprintf(buf, "%d\n", topology_##name(dev->id)); \ } #if defined(topology_thread_cpumask) || defined(topology_core_cpumask) || \ |