From patchwork Sun Nov 5 09:34:17 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: 13445674 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 B22E88C16 for ; Sun, 5 Nov 2023 09:34:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none 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 55CF8C0 for ; Sun, 5 Nov 2023 01:34:43 -0800 (PST) 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 1qzZWd-0000Pd-T4; Sun, 05 Nov 2023 10:34:35 +0100 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 1qzZWb-006l7I-Te; Sun, 05 Nov 2023 10:34:33 +0100 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1qzZWb-00D8nf-KR; Sun, 05 Nov 2023 10:34:33 +0100 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Vinod Koul Cc: Taichi Sugaya , Takao Orito , dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@pengutronix.de Subject: [PATCH 1/4] dmaengine: milbeaut-hdmac: Convert to platform remove callback returning void Date: Sun, 5 Nov 2023 10:34:17 +0100 Message-ID: <20231105093415.3704633-7-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231105093415.3704633-6-u.kleine-koenig@pengutronix.de> References: <20231105093415.3704633-6-u.kleine-koenig@pengutronix.de> Precedence: bulk X-Mailing-List: dmaengine@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2642; i=u.kleine-koenig@pengutronix.de; h=from:subject; bh=iFA5SppBIUUrRTjlHh/H9b168YL1tbBN6Q5z7xRSG+A=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBlR2GYE0b9wUxglKY+saD0HA5khqRUyH857dbZ5 Bg24LiORTKJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCZUdhmAAKCRCPgPtYfRL+ Tt96CACPBr/T5fmGsFg4nVxjGCv2TxQEa7qFpSvVlYTvnfx7FIGt6PIdltD6B3LEJDxvjq27B68 dnpAJsbhXY0ZcmaWX3TGcJrFpazAb1/ogMK6MEsglattVL7+RcLtzbr79qBADdwDaR3RkUUIZAh e8jXRrnxCtXBTL7xqv2rpdkIC2Lv5S8Wseu/SIynz3CdpTxcjzuL8SVVog/BDy+qeHz5mHLoPif jQeWAQiccAHnbnlY+FnerBcCnE65bKjT8iHTABdnb7h4C1jqW7WzT7FX5OObi7sdjqMyjUw/5Bg kizbOnbQZuha5RdvWCCcJeB8c1Teb5DKlG4DjATRUMokhgCp 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: dmaengine@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 ignored (apart from emitting a warning) 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. Eventually after all drivers are converted, .remove_new() will be renamed to .remove(). There is an error path that has the above mentioned problem. This patch only adds a more drastic error message. To properly fix it, dmaengine_terminate_sync() must be known to have succeeded (or that it's safe to not call it as other drivers seem to assume). Signed-off-by: Uwe Kleine-König --- drivers/dma/milbeaut-hdmac.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/dma/milbeaut-hdmac.c b/drivers/dma/milbeaut-hdmac.c index 1b0a95892627..7b41c670970a 100644 --- a/drivers/dma/milbeaut-hdmac.c +++ b/drivers/dma/milbeaut-hdmac.c @@ -531,7 +531,7 @@ static int milbeaut_hdmac_probe(struct platform_device *pdev) return ret; } -static int milbeaut_hdmac_remove(struct platform_device *pdev) +static void milbeaut_hdmac_remove(struct platform_device *pdev) { struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev); struct dma_chan *chan; @@ -546,16 +546,21 @@ static int milbeaut_hdmac_remove(struct platform_device *pdev) */ list_for_each_entry(chan, &mdev->ddev.channels, device_node) { ret = dmaengine_terminate_sync(chan); - if (ret) - return ret; + if (ret) { + /* + * This results in resource leakage and maybe also + * use-after-free errors as e.g. *mdev is kfreed. + */ + dev_alert(&pdev->dev, "Failed to terminate channel %d (%pe)\n", + chan->chan_id, ERR_PTR(ret)); + return; + } milbeaut_hdmac_free_chan_resources(chan); } of_dma_controller_free(pdev->dev.of_node); dma_async_device_unregister(&mdev->ddev); clk_disable_unprepare(mdev->clk); - - return 0; } static const struct of_device_id milbeaut_hdmac_match[] = { @@ -566,7 +571,7 @@ MODULE_DEVICE_TABLE(of, milbeaut_hdmac_match); static struct platform_driver milbeaut_hdmac_driver = { .probe = milbeaut_hdmac_probe, - .remove = milbeaut_hdmac_remove, + .remove_new = milbeaut_hdmac_remove, .driver = { .name = "milbeaut-m10v-hdmac", .of_match_table = milbeaut_hdmac_match,