2 files changed, 28 insertions, 0 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 858b6c0b9a15..dba164bbcc1a 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -910,6 +910,10 @@
                         The filter can be disabled or changed to another
                         driver later using sysfs.
 
+        driver_async_probe=  [KNL]
+                        List of driver names to be probed asynchronously.
+                        Format: <driver_name1>,<driver_name2>...
+
         drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
                         Broken monitors, graphic adapters, KVMs and EDIDless
                         panels may send no or incorrect EDID data sets.
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 348fc4695d4d..a823f469e53f 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -57,6 +57,10 @@ static atomic_t deferred_trigger_count = ATOMIC_INIT(0);
 static struct dentry *deferred_devices;
 static bool initcalls_done;
 
+/* Save the async probe drivers' name from kernel cmdline */
+#define ASYNC_DRV_NAMES_MAX_LEN 256
+static char async_probe_drv_names[ASYNC_DRV_NAMES_MAX_LEN];
+
 /*
  * In some cases, like suspend to RAM or hibernation, It might be reasonable
  * to prohibit probing of devices as it could be unsafe.
@@ -674,6 +678,23 @@ int driver_probe_device(struct device_driver *drv, struct device *dev)
         return ret;
 }
 
+static inline bool cmdline_requested_async_probing(const char *drv_name)
+{
+        return parse_option_str(async_probe_drv_names, drv_name);
+}
+
+/* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
+static int __init save_async_options(char *buf)
+{
+        if (strlen(buf) >= ASYNC_DRV_NAMES_MAX_LEN)
+                printk(KERN_WARNING
+                        "Too long list of driver names for 'driver_async_probe'!\n");
+
+        strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
+        return 0;
+}
+__setup("driver_async_probe=", save_async_options);
+
 bool driver_allows_async_probing(struct device_driver *drv)
 {
         switch (drv->probe_type) {
@@ -684,6 +705,9 @@ bool driver_allows_async_probing(struct device_driver *drv)
                 return false;
 
         default:
+                if (cmdline_requested_async_probing(drv->name))
+                        return true;
+
                 if (module_requested_async_probing(drv->owner))
                         return true;