From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 07 Jun 2023 14:08:51 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1q6ry8-00EJRy-Gj for lore@lore.pengutronix.de; Wed, 07 Jun 2023 14:08:51 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q6ry5-0003wI-Qf for lore@pengutronix.de; Wed, 07 Jun 2023 14:08:50 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ksPHlOfpVjJC+Ulceea/zLezBk5cINgKrRzn7aYbo3k=; b=Iuqo3B999PuTC1S+s88NNB0hso EQ2nV4iitSlKLrE3TRacA050q9/l7SSqQZ3S8iyu2CnBl3HFp/hYZy9ioi75ui8iME9AsZMbdk1si ztoq8KJ4DydV785JBcXmirrcQkqghQ0XCW6DOyIK+BIuOk9Zjy2GwabtTE4jmLBO3KRG03TH1a6s0 6YKQnaGefRMR7piesNX6R3/gwquTfDOTpmnXX4eKEo0ut9kuwOKrNC8ihKvwNwPmVoQ3oFz7Qq1xK BVhS2pGXeP04ej4f8W7Gf3TwuksL38ksjJ7JPJfMH4X8KJPeSmCBrGBWSKT6yhuAQp5GCTcqyco8n ceuhO7zA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q6rwv-005kuT-0j; Wed, 07 Jun 2023 12:07:37 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q6rwl-005knc-0G for barebox@lists.infradead.org; Wed, 07 Jun 2023 12:07:31 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q6rwi-00032x-E6; Wed, 07 Jun 2023 14:07:24 +0200 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1q6rwh-005jkH-NW; Wed, 07 Jun 2023 14:07:23 +0200 Received: from afa by dude05.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1q6rwf-00CyN0-2Z; Wed, 07 Jun 2023 14:07:21 +0200 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 7 Jun 2023 14:07:06 +0200 Message-Id: <20230607120714.3083182-12-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230607120714.3083182-1-a.fatoum@pengutronix.de> References: <20230607120714.3083182-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230607_050727_138523_FEB7144B X-CRM114-Status: GOOD ( 19.85 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.9 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH v2 11/19] cdev: have devfs_add_partition return existing identical partition, not NULL X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) Starting with commit 7f9f45b9bfef ("devfs: Do not create overlapping partitions"), any overlapping is disallowed. Overlapping can be useful though to bridge the gap between partition described in DT and via on-disk partition tables. Let's handle the case of identical partitions specially and have it neither be an error or a duplicate partition, but instead just return the existing partition and create a cdev link to it if the name differs. This existing partition will be given a device tree node and thus enabling schemes like: &{/state} { backend = <&state_part>; }; &mmc1 { partitions { compatible = "fixed-partitions"; #address-cells = <2>; #size-cells = <2>; state_part: partition@5300000 { label = "barebox-state"; /* will be folded with overlapping GPT partition if found */ reg = <0x0 0x5300000 0x0 0x100000>; }; }; }; Signed-off-by: Ahmad Fatoum --- v1 -> v2: - create link to existing cdev if name differs - add identical: goto label to make intent clearer --- fs/devfs-core.c | 57 +++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 46 insertions(+), 11 deletions(-) diff --git a/fs/devfs-core.c b/fs/devfs-core.c index 72a37918962b..c9f7fcfb076d 100644 --- a/fs/devfs-core.c +++ b/fs/devfs-core.c @@ -405,6 +405,12 @@ int devfs_remove(struct cdev *cdev) return 0; } +static bool region_identical(loff_t starta, loff_t lena, + loff_t startb, loff_t lenb) +{ + return starta == startb && lena == lenb; +} + static bool region_overlap(loff_t starta, loff_t lena, loff_t startb, loff_t lenb) { @@ -415,10 +421,22 @@ static bool region_overlap(loff_t starta, loff_t lena, return 1; } -static int check_overlap(struct cdev *cdev, const char *name, loff_t offset, loff_t size) +/** + * check_overlap() - check overlap with existing partitions + * @cdev: parent cdev + * @name: partition name for informational purposes on conflict + * @offset: offset of new partition to be added + * @size: size of new partition to be added + * + * Return: NULL if no overlapping partition found or overlapping + * partition if and only if it's identical in offset and size + * to an existing partition. Otherwise, PTR_ERR(-EINVAL). + */ +static struct cdev *check_overlap(struct cdev *cdev, const char *name, loff_t offset, loff_t size) { struct cdev *cpart; loff_t cpart_offset; + int ret; list_for_each_entry(cpart, &cdev->partitions, partition_entry) { cpart_offset = cpart->offset; @@ -431,20 +449,29 @@ static int check_overlap(struct cdev *cdev, const char *name, loff_t offset, lof if (cpart->mtd) cpart_offset = cpart->mtd->master_offset; - if (region_overlap(cpart_offset, cpart->size, - offset, size)) + if (region_identical(cpart_offset, cpart->size, offset, size)) { + ret = 0; + goto identical; + } + + if (region_overlap(cpart_offset, cpart->size, offset, size)) { + ret = -EINVAL; goto conflict; + } } - return 0; + return NULL; +identical: conflict: - pr_err("New partition %s (0x%08llx-0x%08llx) on %s " - "overlaps with partition %s (0x%08llx-0x%08llx), not creating it\n", - name, offset, offset + size - 1, cdev->name, - cpart->name, cpart_offset, cpart_offset + cpart->size - 1); + __pr_printk(ret ? MSG_WARNING : MSG_DEBUG, + "New partition %s (0x%08llx-0x%08llx) on %s " + "%s with partition %s (0x%08llx-0x%08llx), not creating it\n", + name, offset, offset + size - 1, cdev->name, + ret ? "conflicts" : "identical", + cpart->name, cpart_offset, cpart_offset + cpart->size - 1); - return -EINVAL; + return ret ? ERR_PTR(ret) : cpart; } static struct cdev *__devfs_add_partition(struct cdev *cdev, @@ -452,6 +479,7 @@ static struct cdev *__devfs_add_partition(struct cdev *cdev, { loff_t offset, size; static struct cdev *new; + struct cdev *overlap; if (cdev_by_name(partinfo->name)) return ERR_PTR(-EEXIST); @@ -482,8 +510,15 @@ static struct cdev *__devfs_add_partition(struct cdev *cdev, return ERR_PTR(-EINVAL); } - if (check_overlap(cdev, partinfo->name, offset, size)) - return ERR_PTR(-EINVAL); + overlap = check_overlap(cdev, partinfo->name, offset, size); + if (overlap) { + if (!IS_ERR(overlap)) { + /* only fails with -EEXIST, which is fine */ + (void)devfs_create_link(overlap, partinfo->name); + } + + return overlap; + } if (IS_ENABLED(CONFIG_MTD) && cdev->mtd) { struct mtd_info *mtd; -- 2.39.2