From patchwork Sun Nov 5 09:34:19 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: 13445673 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 3407C8C13 for ; Sun, 5 Nov 2023 09:34:43 +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 8EF0BB7 for ; Sun, 5 Nov 2023 01:34:42 -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-0000Pf-T9; 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 1qzZWc-006l7O-Ak; Sun, 05 Nov 2023 10:34:34 +0100 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1qzZWc-00D8nn-1o; Sun, 05 Nov 2023 10:34:34 +0100 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Vinod Koul Cc: Kunihiko Hayashi , Masami Hiramatsu , dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@pengutronix.de Subject: [PATCH 3/4] dmaengine: uniphier-mdmac: Convert to platform remove callback returning void Date: Sun, 5 Nov 2023 10:34:19 +0100 Message-ID: <20231105093415.3704633-9-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=2640; i=u.kleine-koenig@pengutronix.de; h=from:subject; bh=KteA0sSG4oioIIBmCXZuIP2i8ZzuLBd1ds3YZc/Wpw0=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBlR2GbzQegeQgG49nVuLEjV+AkhupybybvP492w XTJhuZ4chaJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCZUdhmwAKCRCPgPtYfRL+ TpE/CAC1VKU/vpTuUqO+Gq5U0eCAqLliLMByCCgKcNlEW7RJfqye/3E8kl9IZrLo4FhrRcDAuqX wJIlwLTkPVwvtFxcfVl+bu6b28zsv1052aqlS7OcMXl3be+Eu2LmG5c5fMvamZHoLVVjKve90pB 6vVmBX4VG8jDfHuB9oyEhud35+OYkI8eF51lq+wuyo80SCSeGDYW/eBOjQ91UHs0ALmQyuZvjpO QFBLlmPUE677TisT5Qc/rl9+ORNYUmv3ww2bQizxoryjgFj+bfbSlMRB7vtoDxHkmt4Ey3Xm1KI wn8ULnJNoFKrGQf/FmaHtLYpe+T43FVwZXvC21/u0tdxws4m 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/uniphier-mdmac.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/dma/uniphier-mdmac.c b/drivers/dma/uniphier-mdmac.c index 618839df0748..ad7125f6e2ca 100644 --- a/drivers/dma/uniphier-mdmac.c +++ b/drivers/dma/uniphier-mdmac.c @@ -453,7 +453,7 @@ static int uniphier_mdmac_probe(struct platform_device *pdev) return ret; } -static int uniphier_mdmac_remove(struct platform_device *pdev) +static void uniphier_mdmac_remove(struct platform_device *pdev) { struct uniphier_mdmac_device *mdev = platform_get_drvdata(pdev); struct dma_chan *chan; @@ -468,16 +468,21 @@ static int uniphier_mdmac_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; + } uniphier_mdmac_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 uniphier_mdmac_match[] = { @@ -488,7 +493,7 @@ MODULE_DEVICE_TABLE(of, uniphier_mdmac_match); static struct platform_driver uniphier_mdmac_driver = { .probe = uniphier_mdmac_probe, - .remove = uniphier_mdmac_remove, + .remove_new = uniphier_mdmac_remove, .driver = { .name = "uniphier-mio-dmac", .of_match_table = uniphier_mdmac_match,