Re: [PATCH v5 1/6] driver core: Fix driver_deferred_probe_check_state() logic
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From: "Rafael J. Wysocki" <rafael@kernel.org>
Date: 2020-02-25 16:24:28
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On Tue, Feb 25, 2020 at 6:08 AM John Stultz [off-list ref] wrote:
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: Rob Herring <robh@kernel.org> Cc: "Rafael J. Wysocki" <redacted> Cc: Kevin Hilman <khilman@kernel.org> Cc: Ulf Hansson <redacted> Cc: Pavel Machek <redacted> Cc: Len Brown <redacted> Cc: Todd Kjos <redacted> Cc: Saravana Kannan <redacted> Cc: Bjorn Andersson <redacted> Cc: Liam Girdwood <lgirdwood@gmail.com> Cc: Mark Brown <broonie@kernel.org> Cc: Thierry Reding <redacted> Cc: Linus Walleij <redacted> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-pm@vger.kernel.org Signed-off-by: John Stultz <redacted>
Reviewed-by: Rafael J. Wysocki <redacted>
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--- v4: * Simplified logic suggested by Andy Shevchenko * Clarified commit message to focus on logic change v5: * Cleanup comment wording as suggested by Rafael * Tweaked the logic to use Saravana's suggested conditionals --- drivers/base/dd.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)diff --git a/drivers/base/dd.c b/drivers/base/dd.c index b25bcab2a26b..d75b34de6964 100644 --- 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; --2.17.1