From patchwork Thu Sep 14 20:02:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 13385965 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42655266A5 for ; Thu, 14 Sep 2023 20:03:01 +0000 (UTC) Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [IPv6:2a0a:edc0:2:b01:1d::104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7391E26BC for ; Thu, 14 Sep 2023 13:03:00 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qgsYE-00006F-4T; Thu, 14 Sep 2023 22:02:58 +0200 Received: from [2a0a:edc0:0:900:1d::77] (helo=ptz.office.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qgsYB-006NGb-4l; Thu, 14 Sep 2023 22:02:55 +0200 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1qgsYA-001fbf-Rc; Thu, 14 Sep 2023 22:02:54 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Chunfeng Yun , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-mediatek@lists.infradead.org, kernel@pengutronix.de Subject: [PATCH v2] usb: mtu3: Convert to platform remove callback returning void Date: Thu, 14 Sep 2023 22:02:51 +0200 Message-Id: <20230914200251.919584-1-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3339; i=u.kleine-koenig@pengutronix.de; h=from:subject; bh=vg8gEBT4C1SlsEfqTCxI/0BtXyuADwBrBVPRdO7Vs3E=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBlA2bqdPimOIqh+KW+CD5TPCoIzjtlCjSSxLwRz A0PiPugYVSJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCZQNm6gAKCRCPgPtYfRL+ TrtTB/9aRs+Bmk4Iy2g0xqVRF748Mi7m3xP001hO9GGYUzB8srUWVD3CbRdqeErI3UddogWFVWS kXAYTYqdBImIEwxovEjO2Ce6dcP7JXx57TWaJWXKv+Q3fGjGAYe070+erxZYSrIXvMLmg4DmCbe esCjIfAieiHo632Nk+6tNEHkZtOdHYDo0aGt1cFBFGboxcI6x2iBgRWK++Q0LSTUito6lO+87am PEpJeylyVIARPY8CDGd9S+Gq1MCmDcJm83BlThsXreDj3vDYTLRwi4+7qUkniFRA+UVCUdtAZVB Lz4AH+Hw9GpYKf3K4YXfo6+r5iT4T/FFk59suToL8aMIDycm X-Developer-Key: i=u.kleine-koenig@pengutronix.de; a=openpgp; fpr=0D2511F322BFAB1C1580266BE2DCDD9132669BD6 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-usb@vger.kernel.org The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. The function mtu3_remove() can only return a non-zero value if ssusb->dr_mode is neiter USB_DR_MODE_PERIPHERAL nor USB_DR_MODE_HOST nor USB_DR_MODE_OTG. In this case however the probe callback doesn't succeed and so the remove callback isn't called at all. So the code branch resulting in this error path could just be dropped were it not for the compiler choking on "enumeration value 'USB_DR_MODE_UNKNOWN' not handled in switch [-Werror=switch]". So instead replace this code path by a WARN_ON and then mtu3_remove() be converted to return void trivially. Signed-off-by: Uwe Kleine-König --- Changes since (implicit) v1 sent with Message-Id: 20230709163335.3458886-1-u.kleine-koenig@pengutronix.de: - Keep case USB_DR_MODE_UNKNOWN to cope for the compiler being called with -Werror=switch. - Rebase to a newer tree Just to evaluate the options, I tried with a BUG_ON(ssusb->dr_mode == USB_DR_MODE_UNKNOWN) before the switch, but even then gcc insists on the case label for this value. Best regards Uwe drivers/usb/mtu3/mtu3_plat.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) base-commit: 98897dc735cf6635f0966f76eb0108354168fb15 diff --git a/drivers/usb/mtu3/mtu3_plat.c b/drivers/usb/mtu3/mtu3_plat.c index 6f264b129243..18c6cf9a2d71 100644 --- a/drivers/usb/mtu3/mtu3_plat.c +++ b/drivers/usb/mtu3/mtu3_plat.c @@ -451,7 +451,7 @@ static int mtu3_probe(struct platform_device *pdev) return ret; } -static int mtu3_remove(struct platform_device *pdev) +static void mtu3_remove(struct platform_device *pdev) { struct ssusb_mtk *ssusb = platform_get_drvdata(pdev); @@ -469,8 +469,17 @@ static int mtu3_remove(struct platform_device *pdev) ssusb_gadget_exit(ssusb); ssusb_host_exit(ssusb); break; - default: - return -EINVAL; + case USB_DR_MODE_UNKNOWN: + /* + * This cannot happen because with dr_mode == + * USB_DR_MODE_UNKNOWN, .probe() doesn't succeed and so + * .remove() wouldn't be called at all. However (little + * surprising) the compiler isn't smart enough to see that, so + * we explicitly have this case item to not make the compiler + * wail about an unhandled enumeration value. + */ + WARN_ON(1); + break; } ssusb_rscs_exit(ssusb); @@ -478,8 +487,6 @@ static int mtu3_remove(struct platform_device *pdev) pm_runtime_disable(&pdev->dev); pm_runtime_put_noidle(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); - - return 0; } static int resume_ip_and_ports(struct ssusb_mtk *ssusb, pm_message_t msg) @@ -615,7 +622,7 @@ MODULE_DEVICE_TABLE(of, mtu3_of_match); static struct platform_driver mtu3_driver = { .probe = mtu3_probe, - .remove = mtu3_remove, + .remove_new = mtu3_remove, .driver = { .name = MTU3_DRIVER_NAME, .pm = DEV_PM_OPS,