From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Thu, 01 Jun 2023 09:33:20 +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 1q4coD-005UE0-Be for lore@lore.pengutronix.de; Thu, 01 Jun 2023 09:33:20 +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 1q4coA-0002eg-Ou for lore@pengutronix.de; Thu, 01 Jun 2023 09:33:19 +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:From:In-Reply-To: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=glPKtuDZbSzOPkDPdcgCsB6+WaZ7yBQZiJstaHOcbSs=; b=uatkxX680ovOy4DJsyJ5/dwgNa lpDF5HPCn3Jsrbof3nNZEtaYb8JKeYT2xT8gBqvjsWav3CWgIT7WFEtsBKlSTRO65h4F1JhidyRJo LxUzQAmiAFRJuDsAA4QUAOt9gxjI6gjcP2JEuwMd1nXJKcBh/xjrXoHIz/H2DMcPIxLcWsrMFFlvY g5KcBXy/rjSG3O3ULNDyOHy02b/bvOYdlj0ziN98xKBVtkKV/yn9dDqjIPEG1eYYPthRYAdRe/W8U ErKMlBEM7o7FD1JUsslTKpV2LTHP8p+61knILi1hnLULe3JcHH/yfAhtN2C5YoFUU1+7GsNW+Qng5 D83uaJcw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q4cn6-002N2u-1H; Thu, 01 Jun 2023 07:32:12 +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 1q4cn2-002N1Z-25 for barebox@lists.infradead.org; Thu, 01 Jun 2023 07:32:10 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1q4cmz-0002ZD-Mx; Thu, 01 Jun 2023 09:32:05 +0200 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1q4cmz-00024s-Fs; Thu, 01 Jun 2023 09:32:05 +0200 Date: Thu, 1 Jun 2023 09:32:05 +0200 To: Ahmad Fatoum Cc: Marco Felsch , barebox@lists.infradead.org Message-ID: <20230601073205.GG18491@pengutronix.de> References: <20230531145927.1399282-1-a.fatoum@pengutronix.de> <20230531145927.1399282-11-a.fatoum@pengutronix.de> <20230531172305.cgcargl7mcpevmv3@pengutronix.de> <21481bc5-e36f-2bd3-e932-1eb0af71b176@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <21481bc5-e36f-2bd3-e932-1eb0af71b176@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain User-Agent: Mutt/1.10.1 (2018-07-13) From: Sascha Hauer X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230601_003208_687506_79FBF0D6 X-CRM114-Status: GOOD ( 33.19 ) 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=-4.8 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: Re: [PATCH 10/18] 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) On Thu, Jun 01, 2023 at 06:56:47AM +0200, Ahmad Fatoum wrote: > Hello Marco, > > On 31.05.23 19:23, Marco Felsch wrote: > > Hi Ahmad, > > > > On 23-05-31, Ahmad Fatoum wrote: > >> 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. 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 > >> --- > >> fs/devfs-core.c | 50 ++++++++++++++++++++++++++++++++++++++----------- > >> 1 file changed, 39 insertions(+), 11 deletions(-) > >> > >> diff --git a/fs/devfs-core.c b/fs/devfs-core.c > >> index a0732dafca42..b3a274d01ee0 100644 > >> --- a/fs/devfs-core.c > >> +++ b/fs/devfs-core.c > >> @@ -402,6 +402,12 @@ 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) > >> { > >> @@ -412,10 +418,22 @@ 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; > >> @@ -428,20 +446,28 @@ 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 conflict; > >> + } > > > > The 'goto conflict' is a bit misleading here since this is no conflict > > as you described within the commit message. > > It's still a conflict, but one that can be resolved by returning the existing > partition. As a compromise you could use a 'conflict' and 'identical' label and place them directly under each other. No functional change, but makes the intention clearer. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |