From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 28 Oct 2025 11:26:46 +0100 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 1vDguc-00CeaT-0s for lore@lore.pengutronix.de; Tue, 28 Oct 2025 11:26:46 +0100 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 1vDgub-0003cN-MC for lore@pengutronix.de; Tue, 28 Oct 2025 11:26:46 +0100 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:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=JzoYya62oVvj4KhT694AhD5OagqOvNpGX1n0Lr+n9Mc=; b=ahcxru0TSRlFTLkcQh92Xr92AM TgsjrMDFIilaFy3D2WkZW5uCZ1oSx5A4YL8PwzpXHdPRgJPw9ROnBjEoo3SjsEqQPbt0zJn5yQTBM dfI6erWExcjtfmudYoCZ6TlKMxJPtbzzTcKmsOYdf+h2mmZy3h6178sfEE2kPRFJtgaUu5y0hlEgQ NFxmPpdaTEj5JRd5teI1fRF9ZJ+tjgESHLAVZ0R1PBPrxIlYr4qAhU5O+2jGXegCmJXcY6+Wt2LIk y12kOFDE207YYqQY6BORaayrnqIoTAB+pct/RjAmlGrwai1Uv02bj2xsqX1aYDVclGFOZxsuIAEb0 Aw6Zz0Rw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vDgu6-0000000Fl3A-2IfM; Tue, 28 Oct 2025 10:26:14 +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 1vDgu0-0000000Fl1U-1h6W for barebox@lists.infradead.org; Tue, 28 Oct 2025 10:26:12 +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 1vDgtv-0003Vb-3i; Tue, 28 Oct 2025 11:26:03 +0100 Message-ID: <94867b83-cde8-449f-8ed4-d97855831d09@pengutronix.de> Date: Tue, 28 Oct 2025 11:26:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Sascha Hauer , Ahmad Fatoum Cc: barebox@lists.infradead.org References: <20251027075438.2480311-1-a.fatoum@barebox.org> Content-Language: en-US, de-DE, de-BE From: Ahmad Fatoum In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251028_032608_449374_8671245B X-CRM114-Status: GOOD ( 19.92 ) 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=-4.1 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH RFC 1/3] lib: add talloc for overlaying a tree onto allocations 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 10/28/25 10:42 AM, Sascha Hauer wrote: > On Mon, Oct 27, 2025 at 08:54:32AM +0100, Ahmad Fatoum wrote: >> +#ifndef __TALLOC_H__ >> +#define __TALLOC_H__ >> + >> +#include >> + >> +struct talloc { >> + struct talloc *child; >> + struct talloc *next; >> + union { >> + struct talloc *prev; >> + struct talloc *parent; /* Valid only when is_first(mem) */ >> + }; >> +}; > > Currently tlsf allocations are 8 byte aligned. On 32bit architectures > struct talloc will be 12 bytes, so talloc allocations will only have 4 > byte alignment. Good catch. On 32-bit, there is 4 bytes of unused padding inside TLSF and feels bad sacrificing 4 more bytes here. :/ Will have to give it a thought. >> +static void *talloc_ctx_init(struct talloc *hdr, const void *parent) >> +{ >> + void *mem; >> + >> + if (!hdr) >> + return NULL; >> + >> + memset(hdr, 0, sizeof(*hdr)); >> + >> + mem = hdr2mem(hdr); >> + talloc_steal(parent, mem); >> + return mem; >> +} >> + >> +/** >> + * talloc_usable_size() - Report the size of the talloation > > s/talloation/tallocation/ Will fix for v2. > >> + * >> + * @mem: pointer to previously talloc'ed memory chunk. >> + * >> + * Return: size of tallocation >> + */ >> +size_t talloc_usable_size(void *mem) >> +{ >> + return malloc_usable_size(mem) - sizeof(struct talloc); >> +} >> +EXPORT_SYMBOL(talloc_usable_size); > > This function is unused. Do we need it? To make it easier to retrofit normal malloc code for talloc, it's useful to have already, I think. >> +/** >> + * talloc_free() - Deallocate a talloc'ed memory chunk and all the chunks depending on it. >> + * >> + * @mem: pointer to previously talloc'ed memory chunk. >> + */ >> +void talloc_free(void *mem) >> +{ >> + struct talloc *hdr = mem2hdr(mem); >> + >> + if (ZERO_OR_NULL_PTR(hdr)) >> + return; > > For correctness I believe you have to check mem here, not hdr. > > (Although the above works as long as sizeof(struct talloc) <= ZERO_SIZE_PTR) Thanks. This used to be container_of_safe of a flexible data member, which I dropped in the meantime. Will fix for v2. Cheers, Ahmad > > 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 |