[PATCH] driver-core: remove lock for platform devices during probe

From: Wei Li
Date: Mon Apr 24 2017 - 01:43:39 EST


During driver probe procedure, lock on the parent of
platform devices could be removed to make probe in
parallel.

Signed-off-by: Wei Li <weili@xxxxxxxxxxxxxx>
---
drivers/base/dd.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a1fbf55..e238fbc 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -25,6 +25,7 @@
#include <linux/async.h>
#include <linux/pm_runtime.h>
#include <linux/pinctrl/devinfo.h>
+#include <linux/platform_device.h>

#include "base.h"
#include "power/power.h"
@@ -749,13 +750,14 @@ static int __driver_attach(struct device *dev, void *data)
return ret;
} /* ret > 0 means positive match */

- if (dev->parent) /* Needed for USB */
+ if (dev->parent &&
+ (dev->bus != &platform_bus_type)) /* Needed for USB */
device_lock(dev->parent);
device_lock(dev);
if (!dev->driver)
driver_probe_device(drv, dev);
device_unlock(dev);
- if (dev->parent)
+ if (dev->parent && (dev->bus != &platform_bus_type))
device_unlock(dev->parent);

return 0;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project