From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0F57CEB64D7 for ; Tue, 20 Jun 2023 13:20:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aZJcuxcQYbjfC9eLvlMuzDuysZkz01wFePrymjos1uE=; b=wj25CV3eUKnNtu YxAYAkw8ZsprunDe+lXgrQXAiys/hqjRCEIfPgzv6yTsw49tED7n/EXecZZfBwEuUmcEXXw0FC0hE FPYan1oUs5JUoa/sqk2RSORgz3QKBBEvSwFTE8km7RxHEP1+t+xyrDWIFLYMehV/S9U/He1xIeMY9 bCzypr2oaaHHSqAu8Vw4OE/FmuOSCIykqXv/9oy6PG+1N3/WfQuK9tT/4YCrKsVAbSq6Ra51N0JpO Yu2OMnxZe6jQOvviKaEUB4/9Mj2Ln7kovSD8JDzENng7V88B/MZDgvpn+RLrLAvhCEsPe3QGap3T+ hVcBQKu/Ciwa46HWmjyA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qBbHF-00BMdx-2o; Tue, 20 Jun 2023 13:20:09 +0000 Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qBbHD-00BMd4-1n for linux-mtd@lists.infradead.org; Tue, 20 Jun 2023 13:20:08 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1687267207; x=1718803207; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ioFas3xTWzb8p1vfOgeqS8+ZIZhYvxBAQPoT1srDwhE=; b=WHUMFzbRT/OpItdvOO/eZZYgtbO55Y8rA81CcfsxAtaShB+FyiydIEE/ vyTYsUYJsy0m1GiiJK0hVuWGvQxqh7EGN/1AtU7xeIajKEeyslb0ydaS6 2K6um9XI2xnNYmWjNiWM3Um5VTIgnGc6I5ul6msIcn2BQzBXpDoRFmfeN GI2Q9T/tOlU2MgvwStmFDzbzczwvJ5jWbFr2ApeaSuZLVRgz2rIU1RtNq OOatewkdp71+0kHRldHpM4ZjJA7DriEYIBM0opigwvo14ECxclGHZh45/ Aa0oaV5ktP3QFstxFIiiFGbus8AxCwIjCYHK3UemnKz3dQFwgkCWVnwjn w==; X-IronPort-AV: E=McAfee;i="6600,9927,10747"; a="349588300" X-IronPort-AV: E=Sophos;i="6.00,257,1681196400"; d="scan'208";a="349588300" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2023 06:20:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10747"; a="691427007" X-IronPort-AV: E=Sophos;i="6.00,257,1681196400"; d="scan'208";a="691427007" Received: from sannilnx-dsk.jer.intel.com ([10.12.231.107]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2023 06:20:04 -0700 From: Alexander Usyskin To: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Tomas Winkler , Alexander Usyskin , Vitaly Lubart , Andy Shevchenko Subject: [PATCH 2/2] mtd: call external _get and _put in right order Date: Tue, 20 Jun 2023 16:19:05 +0300 Message-Id: <20230620131905.648089-3-alexander.usyskin@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230620131905.648089-1-alexander.usyskin@intel.com> References: <20230620131905.648089-1-alexander.usyskin@intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230620_062007_640746_6AE43312 X-CRM114-Status: GOOD ( 15.30 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org MTD provider provides mtd_info object to mtd subsystem. With kref patch the mtd_info object can be alive after provider released mtd device. Fix calling order in _get and _put functions to allow mtd provider to safely alloc and release mtd object. Execute: 1) call external _get 2) get_module 3) add internal kref in the get function and opposite order in the put one. The _put_device callback should be the last in put as the master struct memory may be freed in this callback. Signed-off-by: Alexander Usyskin --- drivers/mtd/mtdcore.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 84bd1878367d..a5bc60013edf 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1227,21 +1227,20 @@ int __get_mtd_device(struct mtd_info *mtd) struct mtd_info *master = mtd_get_master(mtd); int err; - if (!try_module_get(master->owner)) - return -ENODEV; - - kref_get(&mtd->refcnt); - if (master->_get_device) { err = master->_get_device(mtd); - - if (err) { - kref_put(&mtd->refcnt, mtd_device_release); - module_put(master->owner); + if (err) return err; - } } + if (!try_module_get(master->owner)) { + if (master->_put_device) + master->_put_device(master); + return -ENODEV; + } + + kref_get(&mtd->refcnt); + while (mtd->parent) { if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd->parent != master) kref_get(&mtd->parent->refcnt); @@ -1338,13 +1337,14 @@ void __put_mtd_device(struct mtd_info *mtd) mtd = parent; } - if (master->_put_device) - master->_put_device(master); + if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) + kref_put(&master->refcnt, mtd_device_release); module_put(master->owner); - if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) - kref_put(&master->refcnt, mtd_device_release); + /* must be the last as master can be freed in the _put_device */ + if (master->_put_device) + master->_put_device(master); } EXPORT_SYMBOL_GPL(__put_mtd_device); -- 2.34.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/