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-008dSB-0d 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 1uugWL-0008F1-Ih 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:References:To:Subject:From: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=/EhqLJF5IewVXbxT12Fpc8z5Ux2DbBFd5rEziM0TuiM=; b=hQEGswAAIFiG7nMlbu0pB9TYec hS04e1sDZVFrb/Si+m3F7yNrQ+E8nEArdgxXgkYeoduRqsp9jNYgJeKPH7xskMcMZzGeemKRwG5jT fgyng7Y9JnYLI1f2s34qbTdhbtWX+AldlDHUrAu9l/V8RN/ShpQwUktC0LqX3T7jR8LdInBMzOaVz nN5JH5fmoDlGZZJFbS1h6kVAXsgpL6YtKFYsdt+010auQghy4jZDCGfv7YE8zS1l9WWKiApwW2K9N 1veFP4qzxV13dbQ+i9NNnrY2q0LXVtCXFgYFY8R01YeNjSi2VuKWbaifOslsDa7CtjnlisGhEV7Oe OE7OeX5w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uugVc-00000005RXo-1ze2; Sat, 06 Sep 2025 00:10:24 +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 1uuaD8-00000003TMX-15Tv for barebox@lists.infradead.org; Fri, 05 Sep 2025 17:26:55 +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 1uuaD6-00068S-VJ; Fri, 05 Sep 2025 19:26:53 +0200 Message-ID: <1b9efd77-7c36-4c92-ba0b-cfde134cf6ef@pengutronix.de> Date: Fri, 5 Sep 2025 19:26:52 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Ahmad Fatoum To: Tobias Waldekranz , barebox@lists.infradead.org References: <20250828150637.2222474-1-tobias@waldekranz.com> <20250828150637.2222474-3-tobias@waldekranz.com> Content-Language: en-US, de-DE, de-BE In-Reply-To: <20250828150637.2222474-3-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_102654_299967_44592A1A X-CRM114-Status: GOOD ( 17.12 ) 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 2/5] dm: Add initial device mapper infrastructure 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) Hi, On 8/28/25 5:05 PM, Tobias Waldekranz wrote: > +struct dm_device *dm_create(const char *name, const char *table) > +{ > + struct dm_target *ti; > + struct dm_device *dm; > + int err; > + > + dm = xzalloc(sizeof(*dm)); > + > + dev_set_name(&dm->dev, "%s", name); > + dm->dev.id = DEVICE_ID_SINGLE; > + err = register_device(&dm->dev); > + if (err) > + goto err_free; > + > + INIT_LIST_HEAD(&dm->targets); > + err = dm_parse_table(dm, table); > + if (err) > + goto err_unregister; > + > + dm->blk = (struct block_device) { > + .dev = &dm->dev, > + .cdev = { > + .name = xstrdup(name), > + }, > + > + .type = BLK_TYPE_VIRTUAL, > + .ops = &dm_blk_ops, > + > + .num_blocks = dm_size(dm), > + .blockbits = SECTOR_SHIFT, > + }; > + > + err = blockdevice_register(&dm->blk); > + if (err) > + goto err_destroy; Mhm, don't we have two block caching layers this way? Is this really something we want? For drivers/block/ramdisk.c this was deemed unnecessary, so it opencodes the blockdevice_register. If this makes sense here as well, we could move that code into common/block.c and make it reusable. For now, I think a FIXME alerting to the fact that we have an unnecessary caching step here is enough. Cheers, Ahmad > + > + list_add_tail(&dm->list, &dm_device_list); > + return dm; > + > +err_destroy: > + list_for_each_entry_reverse(ti, &dm->targets, list) { > + ti->ops->destroy(ti); > + } > + > +err_unregister: > + unregister_device(&dm->dev); > + > +err_free: > + free(dm); > + return ERR_PTR(err); > +} > +EXPORT_SYMBOL(dm_create); > diff --git a/drivers/block/dm/dm-target.h b/drivers/block/dm/dm-target.h > new file mode 100644 > index 0000000000..506e808b79 > --- /dev/null > +++ b/drivers/block/dm/dm-target.h > @@ -0,0 +1,39 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* SPDX-FileCopyrightText: © 2025 Tobias Waldekranz , Wires */ > + > +#ifndef __DM_TARGET_H > +#define __DM_TARGET_H > + > +struct dm_device; > +struct dm_target_ops; > + > +struct dm_target { > + struct dm_device *dm; > + struct list_head list; > + > + sector_t base; > + blkcnt_t size; > + > + const struct dm_target_ops *ops; > + void *private; > +}; > + > +void dm_target_err(struct dm_target *ti, const char *fmt, ...); > + > +struct dm_target_ops { > + struct list_head list; > + const char *name; > + > + char *(*asprint)(struct dm_target *ti); > + int (*create)(struct dm_target *ti, unsigned int argc, char **argv); > + int (*destroy)(struct dm_target *ti); > + int (*read)(struct dm_target *ti, void *buf, > + sector_t block, blkcnt_t num_blocks); > + int (*write)(struct dm_target *ti, const void *buf, > + sector_t block, blkcnt_t num_blocks); > +}; > + > +int dm_target_register(struct dm_target_ops *ops); > +void dm_target_unregister(struct dm_target_ops *ops); > + > +#endif /* __DM_TARGET_H */ > diff --git a/include/dm.h b/include/dm.h > new file mode 100644 > index 0000000000..255796ca2f > --- /dev/null > +++ b/include/dm.h > @@ -0,0 +1,16 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > + > +#ifndef __DM_H > +#define __DM_H > + > +struct dm_device; > + > +struct dm_device *dm_find_by_name(const char *name); > +int dm_foreach(int (*cb)(struct dm_device *dm, void *ctx), void *ctx); > + > +char *dm_asprint(struct dm_device *dm); > + > +void dm_destroy(struct dm_device *dm); > +struct dm_device *dm_create(const char *name, const char *ctable); > + > +#endif /* __DM_H */ -- 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 |