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 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.lore.kernel.org (Postfix) with ESMTPS id 6A4BAFD063E for ; Wed, 11 Mar 2026 07:09:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=grGjLvbH0NtGWH1Qsz+POdQ3oOwgEsaRytI5JJKjDE8=; b=xbL5t8w+1WvkR/ QdT5OZaLQ69UFyV1sYKO+5wUVfmTbQ1ZSVjK5Zfl4y5aPxuohaYsaATSaJlfYXDryPEUKXzB/fxCG fBc1nJZeGU+dQiZZs3gUllUNL2X9u6XuxTAxlj6fOVxvPUeyQZLv3kZvM641jtaE64HKqDC4id5s+ HZbX4qRQnn22rrjm5xOBAnQmEyeRUzXWeUxy4m4mhXCIo+ftD71rdfJZyR1gWFgRQpn47grcW+ohN qlH/mBfSNS4jgVUih0MMH2gkti2DMuK7KtW/l1Gl1zIL8o0FlJ4o1ve/uZCrxHgsPHlS3AusugeZS qH6WZIo6qgLJFaPfuFQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w0Dh7-0000000B10p-1Q3X; Wed, 11 Mar 2026 07:09:25 +0000 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> MIME-Version: 1.0 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv