do_initcalls() could call all driver initialization code in kernel_init
thread. It means that probe() function will be also called from that
time. After this, kernel could access console & release __init section
in the same thread.
But if device probe fails and moves into deferred probe list, a new
thread is created to reinvoke probe. If the device is serial console,
kernel has to open console failure & release __init section before
reinvoking failure. Because there's no synchronization mechanism.
Now add wait event to synchronize after do_initcalls().
Signed-off-by: Haojian Zhuang <haojian.zhu...@linaro.org>
---
drivers/base/dd.c | 8 +++++---
init/main.c | 1 +
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 65631015..23db672 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -53,6 +53,9 @@ static LIST_HEAD(deferred_probe_pending_list);
static LIST_HEAD(deferred_probe_active_list);
static struct workqueue_struct *deferred_wq;
+static atomic_t probe_count = ATOMIC_INIT(0);
+static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
+
/**
* deferred_probe_work_func() - Retry probing devices in the active list.
*/
@@ -77,6 +80,7 @@ static void deferred_probe_work_func(struct work_struct *work)
private = list_first_entry(&deferred_probe_active_list,
typeof(*dev->p), deferred_probe);
dev = private->device;
+ atomic_dec(&probe_count);
list_del_init(&private->deferred_probe);
get_device(dev);
@@ -257,9 +261,6 @@ int device_bind_driver(struct device *dev)
}
EXPORT_SYMBOL_GPL(device_bind_driver);
-static atomic_t probe_count = ATOMIC_INIT(0);
-static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);
-
static int really_probe(struct device *dev, struct device_driver *drv)
{
int ret = 0;
@@ -308,6 +309,7 @@ probe_failed:
/* Driver requested deferred probing */
dev_info(dev, "Driver %s requests probe deferral\n", drv->name);
driver_deferred_probe_add(dev);
+ atomic_inc(&probe_count);
} else if (ret != -ENODEV && ret != -ENXIO) {
/* driver matched but the probe failed */
printk(KERN_WARNING
diff --git a/init/main.c b/init/main.c
index 63534a1..033bf5f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -786,6 +786,7 @@ static void __init do_basic_setup(void)
do_ctors();
usermodehelper_enable();
do_initcalls();
+ wait_for_device_probe();
}
static void __init do_pre_smp_initcalls(void)
--
1.7.10.4
--
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