driver core: Add "*" wildcard support to driver_async_probe cmdline param

There's currently no way to use driver_async_probe kernel cmdline param
to enable default async probe for all drivers.  So, add support for "*"
to match with all driver names.  When "*" is used, all other drivers
listed in driver_async_probe are drivers that will NOT match the "*".

For example:
* driver_async_probe=drvA,drvB,drvC
  drvA, drvB and drvC do asynchronous probing.

* driver_async_probe=*
  All drivers do asynchronous probing except those that have set
  PROBE_FORCE_SYNCHRONOUS flag.

* driver_async_probe=*,drvA,drvB,drvC
  All drivers do asynchronous probing except drvA, drvB, drvC and those
  that have set PROBE_FORCE_SYNCHRONOUS flag.

Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20220504005344.117803-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 3f1cc5e..c7513d0 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1076,7 +1076,10 @@
                        driver later using sysfs.
 
        driver_async_probe=  [KNL]
-                       List of driver names to be probed asynchronously.
+                       List of driver names to be probed asynchronously. *
+                       matches with all driver names. If * is specified, the
+                       rest of the listed driver names are those that will NOT
+                       match the *.
                        Format: <driver_name1>,<driver_name2>...
 
        drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 39c70fc..810f45c 100644 (file)
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -60,6 +60,7 @@ 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];
+static bool async_probe_default;
 
 /*
  * In some cases, like suspend to RAM or hibernation, It might be reasonable
@@ -797,7 +798,11 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev)
 
 static inline bool cmdline_requested_async_probing(const char *drv_name)
 {
-       return parse_option_str(async_probe_drv_names, drv_name);
+       bool async_drv;
+
+       async_drv = parse_option_str(async_probe_drv_names, drv_name);
+
+       return (async_probe_default != async_drv);
 }
 
 /* The option format is "driver_async_probe=drv_name1,drv_name2,..." */
@@ -807,6 +812,8 @@ static int __init save_async_options(char *buf)
                pr_warn("Too long list of driver names for 'driver_async_probe'!\n");
 
        strlcpy(async_probe_drv_names, buf, ASYNC_DRV_NAMES_MAX_LEN);
+       async_probe_default = parse_option_str(async_probe_drv_names, "*");
+
        return 1;
 }
 __setup("driver_async_probe=", save_async_options);