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Wysocki" Subject: [PATCH 2/2] driver core: platform: simplify __platform_driver_probe() Date: Tue, 31 Jan 2023 09:24:59 +0100 Message-Id: <20230131082459.301603-2-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230131082459.301603-1-gregkh@linuxfoundation.org> References: <20230131082459.301603-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2285; i=gregkh@linuxfoundation.org; h=from:subject; bh=F1oXVOG/G5R87LGJbW98rwPjWbBIBnHqxHXX0+MontQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDMk3LkS/Fp4uXRy0K18ya+/V35ZSxmKTrtdxWa12S93r8Wfb ndR3HbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCR/q8MCzbd2vCxr7+HzzK/7ax+5a 996c86HBnmqVw87J6hNXHS0/KjWq+OzYkuNmO/BwA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1756526289868236290?= X-GMAIL-MSGID: =?utf-8?q?1756526289868236290?= __platform_driver_probe() pokes around in some bus and driver private lists and locks in a way that is not needed at all. The code only wants to know if a device was bound to the driver that was registered, so walk all devices on the bus to see if there was a match. If there is not a match, return an error. This is the same logic as was originally present, but just done in a simpler and more obvious way that is not a layering violation. Cc: "Rafael J. Wysocki" Signed-off-by: Greg Kroah-Hartman --- drivers/base/platform.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 423874269f9d..77510e4f47de 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -883,6 +883,13 @@ static int platform_probe_fail(struct platform_device *pdev) return -ENXIO; } +static int is_bound_to_driver(struct device *dev, void *driver) +{ + if (dev->driver == driver) + return 1; + return 0; +} + /** * __platform_driver_probe - register driver for non-hotpluggable device * @drv: platform driver structure @@ -936,20 +943,17 @@ int __init_or_module __platform_driver_probe(struct platform_driver *drv, if (retval) return retval; - /* - * Fixup that section violation, being paranoid about code scanning - * the list of drivers in order to probe new devices. Check to see - * if the probe was successful, and make sure any forced probes of - * new devices fail. - */ - spin_lock(&drv->driver.bus->p->klist_drivers.k_lock); + /* Force all new probes of this driver to fail */ drv->probe = platform_probe_fail; - if (list_empty(&drv->driver.p->klist_devices.k_list)) - retval = -ENODEV; - spin_unlock(&drv->driver.bus->p->klist_drivers.k_lock); - if (retval) + /* Walk all platform devices and see if any actually bound to this driver. + * If not, return an error as the device should have done so by now. + */ + if (!bus_for_each_dev(&platform_bus_type, NULL, &drv->driver, is_bound_to_driver)) { + retval = -ENODEV; platform_driver_unregister(drv); + } + return retval; } EXPORT_SYMBOL_GPL(__platform_driver_probe);