driver core: Fix driver_deferred_probe_check_state() logic

driver_deferred_probe_check_state() has some uninituitive behavior.

* From boot to late_initcall, it returns -EPROBE_DEFER

* From late_initcall to the deferred_probe_timeout (if set)
  it returns -ENODEV

* If the deferred_probe_timeout it set, after it fires, it
  returns -ETIMEDOUT

This is a bit confusing, as its useful to have the function
return -EPROBE_DEFER while the timeout is still running. This
behavior has resulted in the somwhat duplicative
driver_deferred_probe_check_state_continue() function being
added.

Thus this patch tries to improve the logic, so that it behaves
as such:

* If late_initcall has passed, and modules are not enabled
  it returns -ENODEV

* If modules are enabled and deferred_probe_timeout is set,
  it returns -EPROBE_DEFER until the timeout, afterwhich it
  returns -ETIMEDOUT.

* In all other cases, it returns -EPROBE_DEFER

This will make the deferred_probe_timeout value much more
functional, and will allow us to consolidate the
driver_deferred_probe_check_state() and
driver_deferred_probe_check_state_continue() logic in a later
patch.

Cc: [email protected]
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Thierry Reding <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Liam Girdwood <[email protected]>
Cc: Bjorn Andersson <[email protected]>
Cc: Saravana Kannan <[email protected]>
Cc: Todd Kjos <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Rob Herring <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index b25bcab2a26bd2adb8e7e975d7ff9f4cc5ea0cca..d75b34de69644e5dcd402382e795daeddcbd2a49 100644 (file)
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -237,24 +237,26 @@ __setup("deferred_probe_timeout=", deferred_probe_timeout_setup);
 
 static int __driver_deferred_probe_check_state(struct device *dev)
 {
-       if (!initcalls_done)
-               return -EPROBE_DEFER;
+       if (!IS_ENABLED(CONFIG_MODULES) && initcalls_done)
+               return -ENODEV;
 
        if (!deferred_probe_timeout) {
                dev_WARN(dev, "deferred probe timeout, ignoring dependency");
                return -ETIMEDOUT;
        }
 
-       return 0;
+       return -EPROBE_DEFER;
 }
 
 /**
  * driver_deferred_probe_check_state() - Check deferred probe state
  * @dev: device to check
  *
- * Returns -ENODEV if init is done and all built-in drivers have had a chance
- * to probe (i.e. initcalls are done), -ETIMEDOUT if deferred probe debug
- * timeout has expired, or -EPROBE_DEFER if none of those conditions are met.
+ * Return:
+ * -ENODEV if initcalls have completed and modules are disabled.
+ * -ETIMEDOUT if the deferred probe timeout was set and has expired
+ *  and modules are enabled.
+ * -EPROBE_DEFER in other cases.
  *
  * Drivers or subsystems can opt-in to calling this function instead of directly
  * returning -EPROBE_DEFER.
@@ -264,7 +266,7 @@ int driver_deferred_probe_check_state(struct device *dev)
        int ret;
 
        ret = __driver_deferred_probe_check_state(dev);
-       if (ret < 0)
+       if (ret != -ENODEV)
                return ret;
 
        dev_warn(dev, "ignoring dependency for device, assuming no driver");
@@ -292,7 +294,7 @@ int driver_deferred_probe_check_state_continue(struct device *dev)
        int ret;
 
        ret = __driver_deferred_probe_check_state(dev);
-       if (ret < 0)
+       if (ret != -ENODEV)
                return ret;
 
        return -EPROBE_DEFER;