From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EFDC73909A2; Wed, 11 Mar 2026 07:09:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773212979; cv=none; b=gWwgke74ygt+4OhO46UNS2aBRtWqbCdg4SH20Mxte4jDwMGX3Mykjsv832NvC8XA3K0hbgMm6ZB0rK3q1C02Db6Oc58NRj3RBd0rchq3aX8YAhNJfEmNtX4lPOqNbH9/hsC7fEsa4p36nbnnPX/kidaP48Zr3aKa0k06tmSqdDg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773212979; c=relaxed/simple; bh=9RQhp6tuaXpfHOrHQCgCLw2CBD4KxYV1pfp+3QrIzWk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Rs95yNJbNvaOZFD/22cFrx/AEidX4b3KVgDFJysxVx9aqN3QzLy6BWL8C21OByKOetd1hg8Zn5Oah1aalGtiCbmeGQ0PzY0ST44l7mRYzsvq3F/EtWLtkXzWlk4xgGqZol0RoqJlcCifmkSzHHQMUh7p3BZvTMvTUM549X6vugE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=2AOHWBeq; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="2AOHWBeq" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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