From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CD41DFD0640 for ; Wed, 11 Mar 2026 07:09:40 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4fW21b2bVjz3dVH; Wed, 11 Mar 2026 18:09:39 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:7c80:54:3::133" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1773212979; cv=none; b=G5UMagMNuQ00wQwtb6K+MpIc/c+ldzYGIb9w/OUkVAz6c/yMGwgMtUzDl+wIaFzMKeV3i6SdrF8Z11ybqK6l3jza9UM5eDWoZmMGhbJoyh85yy5Kafkz2iihOxyUkuuTHLTo8fTVGl6971ORQ8JIAJDfitTGnN2NldrYsIJsEPk09ZljFGfxyILm9JGVWAu7wJOMxutVVfkLRe5+6o2OLiXkGU1c8VPrLxQnuWW6iz17FzyB6VBrIMpZr0STo2SYvpZYK4lcov0qQPppE6MriN+Quao3rt5mT3wU6xRVIFnlzknuAuUue9cHcyJSbGSSb5xEoF2pyeJuVwVEzVeLOQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1773212979; c=relaxed/relaxed; bh=9fvnUIU7nYzp+spbrgNcfNOp4SrOTES6+fJpo+CBdYA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GR7pPz0Po0ajrEqlGV+IRqg/uw8xHCwq44ERUnaVgYFwMWDlsMaB53GQBBoYJZcCUvFoMgOldfeOy4LOiVgmMwtqOMd0Ez1INqqYJG7+3ArAPqbsqTQG8jRdGwpjk8y3z0oTXOzDo/rq8kGiEb0BP4JZCgW9NcoqBxQoFwjFsXIMW608GJ4ZEgxidz1n4Wr/SU+PtLMApF47ZxVPa35V7laTHeVsw4WlORl+M0U5p6dw9ZBdNpT4fdDmSNCuyF+xE25ZrWpp6h+xFjOukEniWV3E8txlKEQnuO+LKFGdOMkby/BFKVuOn/Wxn8U4K3tG5x9NvSS42kjEw2HSMurNCg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=fail (p=none dis=none) header.from=lst.de; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=2AOHWBeq; dkim-atps=neutral; spf=none (client-ip=2607:7c80:54:3::133; helo=bombadil.infradead.org; envelope-from=batv+bcc67bb7b2d0717eac20+8235+infradead.org+hch@bombadil.srs.infradead.org; receiver=lists.ozlabs.org) smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: lists.ozlabs.org; dmarc=fail (p=none dis=none) header.from=lst.de Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=2AOHWBeq; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=bombadil.srs.infradead.org (client-ip=2607:7c80:54:3::133; helo=bombadil.infradead.org; envelope-from=batv+bcc67bb7b2d0717eac20+8235+infradead.org+hch@bombadil.srs.infradead.org; receiver=lists.ozlabs.org) Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4fW21Z5kpKz3dTw for ; Wed, 11 Mar 2026 18:09:38 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=9fvnUIU7nYzp+spbrgNcfNOp4SrOTES6+fJpo+CBdYA=; b=2AOHWBeqnBOKCbCqQD/Dv51tWP FhXGZ7dxnT3Wb6tan/33z+XTuAVt1CAJLx+4IN6HHcPtmoOx4pYyP0mh3LR9IrzRSx3j6c6nB0SxF cBJudpV23GMI+nuXXVdwlKcZgUT0EDn3aZEJqgK9ZesGu7KAmeIf3I21n9iWPal2aO4IcWTRa+IT/ Gw2kISYfXpS+3+SUjl0qj4IeLF07yy5VGCVBHD/r36qMuKLtNhJhxsZHQEZw5dOZd3LGKslQhB0Fr ofzOddPTw5xuXpto3KmykY0xyei2og7OtC5N5t/EsgYOx/Lc0LyY1xjeTQyqx05o9bCHORVE9Jepj a5Luyefw==; Received: from [212.243.42.10] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w0Dh3-0000000B0qJ-3xXB; Wed, 11 Mar 2026 07:09:22 +0000 From: Christoph Hellwig To: Andrew Morton Cc: Richard Henderson , Matt Turner , Magnus Lindholm , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "David S. Miller" , Andreas Larsson , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Herbert Xu , Dan Williams , Chris Mason , David Sterba , Arnd Bergmann , Song Liu , Yu Kuai , Li Nan , "Theodore Ts'o" , "Jason A. Donenfeld" , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-arch@vger.kernel.org, linux-raid@vger.kernel.org Subject: [PATCH 21/27] xor: add a better public API Date: Wed, 11 Mar 2026 08:03:53 +0100 Message-ID: <20260311070416.972667-22-hch@lst.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260311070416.972667-1-hch@lst.de> References: <20260311070416.972667-1-hch@lst.de> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html xor_blocks is very annoying to use, because it is limited to 4 + 1 sources / destinations, has an odd argument order and is completely undocumented. Lift the code that loops around it from btrfs and async_tx/async_xor into common code under the name xor_gen and properly document it. Signed-off-by: Christoph Hellwig --- include/linux/raid/xor.h | 2 ++ lib/raid/xor/xor-core.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/include/linux/raid/xor.h b/include/linux/raid/xor.h index 02bda8d99534..6d9a39fd85dd 100644 --- a/include/linux/raid/xor.h +++ b/include/linux/raid/xor.h @@ -7,4 +7,6 @@ extern void xor_blocks(unsigned int count, unsigned int bytes, void *dest, void **srcs); +void xor_gen(void *dest, void **srcs, unsigned int src_cnt, unsigned int bytes); + #endif /* _XOR_H */ diff --git a/lib/raid/xor/xor-core.c b/lib/raid/xor/xor-core.c index 47e09ae954b2..64f12f579e96 100644 --- a/lib/raid/xor/xor-core.c +++ b/lib/raid/xor/xor-core.c @@ -46,6 +46,38 @@ xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs) } EXPORT_SYMBOL(xor_blocks); +/** + * xor_gen - generate RAID-style XOR information + * @dest: destination vector + * @srcs: source vectors + * @src_cnt: number of source vectors + * @bytes: length in bytes of each vector + * + * Performs bit-wise XOR operation into @dest for each of the @src_cnt vectors + * in @srcs for a length of @bytes bytes. @src_count must be non-zero, and the + * memory pointed to by @dest and each member of @srcs must be at least 32-byte + * aligned. @bytes must be non-zero and a multiple of 512. + * + * Note: for typical RAID uses, @dest either needs to be zeroed, or filled with + * the first disk, which then needs to be removed from @srcs. + */ +void xor_gen(void *dest, void **srcs, unsigned int src_cnt, unsigned int bytes) +{ + unsigned int src_off = 0; + + WARN_ON_ONCE(bytes & 511); + + while (src_cnt > 0) { + unsigned int this_cnt = min(src_cnt, MAX_XOR_BLOCKS); + + xor_blocks(this_cnt, bytes, dest, srcs + src_off); + + src_cnt -= this_cnt; + src_off += this_cnt; + } +} +EXPORT_SYMBOL(xor_gen); + /* Set of all registered templates. */ static struct xor_block_template *__initdata template_list; static bool __initdata xor_forced = false; -- 2.47.3