From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Sat, 06 Sep 2025 02:11:12 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uugWP-008dSC-0l for lore@lore.pengutronix.de; Sat, 06 Sep 2025 02:11:12 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uugWM-0008FC-3V for lore@pengutronix.de; Sat, 06 Sep 2025 02:11:12 +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: Content-Type:In-Reply-To:From:References:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/byWb0BGpC+RPSgPBy4U8MjBvEGjAJG9mB0CcbZ3GV4=; b=g/IUTKhPdez6yWnIsqJDhkILZK 7vktgDQl80EMyzHLDZ/hv+m1AytiwQ09uA/2k2IgdNnWohmQoYpwrLiJJZU9HL0qwexoUxITj0gA4 6xeKh7CklXl/+LioBtvMJoUsWsfFhwtldYFCn012LMAK7SPNdpFG8Cq5uOu//8ZbnzvlJbiUBNLQd rb+Z1IyyKi/DQv3V+eZA/k1WIEPBkynrjIdylQNvMkpcaoJSVm3zXuO5OcTwuInzqHI+B+QLRDb1D p5g2PxAx/4HR7AC7wcbG8iuWmPmX3rHpyCu6+tNP+e5FBkkAtDBuLDlPPvxY5oNNCBFD0ykCoxBAK 22uKHDlw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uugVQ-00000005RAo-2tQP; Sat, 06 Sep 2025 00:10:12 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uuZRg-000000039pg-0koZ for barebox@lists.infradead.org; Fri, 05 Sep 2025 16:37:53 +0000 Received: from ptz.office.stw.pengutronix.de ([2a0a:edc0:0:900:1d::77] helo=[127.0.0.1]) by metis.whiteo.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1uuZRe-0004cF-T6; Fri, 05 Sep 2025 18:37:50 +0200 Message-ID: <5dc919d3-eb60-47ec-81ee-b0e81423563a@pengutronix.de> Date: Fri, 5 Sep 2025 18:37:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Tobias Waldekranz , barebox@lists.infradead.org References: <20250828150637.2222474-1-tobias@waldekranz.com> <20250828150637.2222474-4-tobias@waldekranz.com> Content-Language: en-US, de-DE, de-BE From: Ahmad Fatoum In-Reply-To: <20250828150637.2222474-4-tobias@waldekranz.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250905_093752_223937_C3ADAF85 X-CRM114-Status: GOOD ( 27.65 ) 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.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-5.3 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 autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH 3/5] dm: linear: Add linear target X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) On 8/28/25 5:05 PM, Tobias Waldekranz wrote: > This target allows you to map in a region of another device as a > contiguous range of blocks of a dm device. > > This is the basic building block used by LVM to stitch together > logical volumes from one or more ranges of blocks from one or more > physical disks. > > Signed-off-by: Tobias Waldekranz > --- > drivers/block/dm/Kconfig | 7 ++ > drivers/block/dm/Makefile | 1 + > drivers/block/dm/dm-linear.c | 123 +++++++++++++++++++++++++++++++++++ > 3 files changed, 131 insertions(+) > create mode 100644 drivers/block/dm/dm-linear.c > > diff --git a/drivers/block/dm/Kconfig b/drivers/block/dm/Kconfig > index f64c69e03d..e763e530d3 100644 > --- a/drivers/block/dm/Kconfig > +++ b/drivers/block/dm/Kconfig > @@ -5,3 +5,10 @@ menuconfig DM_BLK > other data sources. Modeled after, and intended to be > compatible with, the Linux kernel's device mapper subsystem. > > +config DM_BLK_LINEAR > + bool "Linear target" > + depends on DM_BLK Tab/Spaces mix up. > + help > + Maps a contiguous region of an existing device into a dm > + device. > + > diff --git a/drivers/block/dm/Makefile b/drivers/block/dm/Makefile > index 9c045087c0..f52d19f9c4 100644 > --- a/drivers/block/dm/Makefile > +++ b/drivers/block/dm/Makefile > @@ -1,2 +1,3 @@ > # SPDX-License-Identifier: GPL-2.0-only > obj-$(CONFIG_DM_BLK) += dm-core.o > +obj-$(CONFIG_DM_BLK_LINEAR) += dm-linear.o > diff --git a/drivers/block/dm/dm-linear.c b/drivers/block/dm/dm-linear.c > new file mode 100644 > index 0000000000..d3415814cb > --- /dev/null > +++ b/drivers/block/dm/dm-linear.c > @@ -0,0 +1,123 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +// SPDX-FileCopyrightText: © 2025 Tobias Waldekranz , Wires > + > +#include > +#include Nitpick: If possible, I'd like to avoid common.h in new code. It's a lot of unneeded stuff in there. > +#include > +#include > + > +#include "dm-target.h" > + > +struct dm_linear { > + struct cdev *cdev; > + loff_t offset; > +}; > + > +static int dm_linear_read(struct dm_target *ti, void *buf, > + sector_t block, blkcnt_t num_blocks) > +{ > + struct dm_linear *l = ti->private; > + > + block <<= SECTOR_SHIFT; > + num_blocks <<= SECTOR_SHIFT; > + > + if (cdev_read(l->cdev, buf, num_blocks, l->offset + block, 0) < num_blocks) > + return -EIO; Why not propagate the underlying error code if it's negative? > + > + return 0; > +} > + > +static int dm_linear_write(struct dm_target *ti, const void *buf, > + sector_t block, blkcnt_t num_blocks) > +{ > + struct dm_linear *l = ti->private; > + > + block <<= SECTOR_SHIFT; > + num_blocks <<= SECTOR_SHIFT; > + > + if (cdev_write(l->cdev, buf, num_blocks, l->offset + block, 0) < num_blocks) > + return -EIO; > + > + return 0; > +} > + > +static int dm_linear_create(struct dm_target *ti, unsigned int argc, char **argv) > +{ > + struct dm_linear *l; > + int err; > + > + if (argc != 2) { > + dm_target_err(ti, "Expected 2 arguments (\" \"), got %u\n", > + argc); > + err = -EINVAL; > + goto err; > + } > + > + l = xzalloc(sizeof(*l)); > + ti->private = l; > + > + if (kstrtoull(argv[1], 0, &l->offset)) { > + dm_target_err(ti, "Invalid offset: \"%s\"\n", argv[1]); > + err = -EINVAL; > + goto err_free; > + } > + l->offset <<= SECTOR_SHIFT; > + > + l->cdev = cdev_open_by_path_name(argv[0], O_RDWR); > + if (!l->cdev) { > + dm_target_err(ti, "Cannot open device %s: %m\n", argv[0]); > + err = -ENODEV; > + goto err_free; > + } > + > + l->cdev = cdev_readlink(l->cdev); > + > + if ((ti->size << SECTOR_SHIFT) > (l->cdev->size - l->offset)) { > + dm_target_err(ti, "%s is too small to map %llu blocks at %llu, %llu available\n", > + argv[0], ti->size, l->offset >> SECTOR_SHIFT, > + (l->cdev->size - l->offset) >> SECTOR_SHIFT); > + err = -ENOSPC; > + goto err_close; > + } > + > + return 0; > + > +err_close: > + cdev_close(l->cdev); > +err_free: > + free(l); > +err: > + return err; > +} > + > +static int dm_linear_destroy(struct dm_target *ti) > +{ > + struct dm_linear *l = ti->private; > + > + cdev_close(l->cdev); > + free(l); > + return 0; > +} > + > +static char *dm_linear_asprint(struct dm_target *ti) > +{ > + struct dm_linear *l = ti->private; > + > + return xasprintf("dev:%s offset:%llu", > + cdev_name(l->cdev), l->offset >> SECTOR_SHIFT); > +} > + > +static struct dm_target_ops dm_linear_ops = { > + .name = "linear", > + .asprint = dm_linear_asprint, > + .create = dm_linear_create, > + .destroy = dm_linear_destroy, > + .read = dm_linear_read, > + .write = dm_linear_write, > +}; > + > +static int __init dm_linear_init(void) > +{ > + return dm_target_register(&dm_linear_ops); > +} > +device_initcall(dm_linear_init); -- 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 |