From patchwork Mon Jan 18 16:30:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 12027691 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85E59C433DB for ; Mon, 18 Jan 2021 16:32:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5280D22BE9 for ; Mon, 18 Jan 2021 16:32:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406780AbhARQbz (ORCPT ); Mon, 18 Jan 2021 11:31:55 -0500 Received: from smtp.infotech.no ([82.134.31.41]:45763 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbhARQbs (ORCPT ); Mon, 18 Jan 2021 11:31:48 -0500 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id 55D67204295; Mon, 18 Jan 2021 17:30:32 +0100 (CET) X-Virus-Scanned: by amavisd-new-2.6.6 (20110518) (Debian) at infotech.no Received: from smtp.infotech.no ([127.0.0.1]) by localhost (smtp.infotech.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id hNUSQtqmjh3E; Mon, 18 Jan 2021 17:30:28 +0100 (CET) Received: from xtwo70.bingwo.ca (host-104-157-204-209.dyn.295.ca [104.157.204.209]) by smtp.infotech.no (Postfix) with ESMTPA id 666E4204279; Mon, 18 Jan 2021 17:30:25 +0100 (CET) From: Douglas Gilbert To: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, target-devel@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, bostroesser@gmail.com, ddiss@suse.de, bvanassche@acm.org, jgg@ziepe.ca Subject: [PATCH v6 4/4] scatterlist: add sgl_memset() Date: Mon, 18 Jan 2021 11:30:06 -0500 Message-Id: <20210118163006.61659-5-dgilbert@interlog.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210118163006.61659-1-dgilbert@interlog.com> References: <20210118163006.61659-1-dgilbert@interlog.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org The existing sg_zero_buffer() function is a bit restrictive. For example protection information (PI) blocks are usually initialized to 0xff bytes. As its name suggests sgl_memset() is modelled on memset(). One difference is the type of the val argument which is u8 rather than int. Plus it returns the number of bytes (over)written. Change implementation of sg_zero_buffer() to call this new function. Reviewed-by: Bodo Stroesser Signed-off-by: Douglas Gilbert --- include/linux/scatterlist.h | 20 +++++++++- lib/scatterlist.c | 79 +++++++++++++++++++++---------------- 2 files changed, 62 insertions(+), 37 deletions(-) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 71be65f9ebb5..69e87280b44d 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -318,8 +318,6 @@ size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, const void *buf, size_t buflen, off_t skip); size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, size_t buflen, off_t skip); -size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, - size_t buflen, off_t skip); size_t sgl_copy_sgl(struct scatterlist *d_sgl, unsigned int d_nents, off_t d_skip, struct scatterlist *s_sgl, unsigned int s_nents, off_t s_skip, @@ -333,6 +331,24 @@ bool sgl_compare_sgl_idx(struct scatterlist *x_sgl, unsigned int x_nents, off_t struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, size_t n_bytes, size_t *miscompare_idx); +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, + u8 val, size_t n_bytes); + +/** + * sg_zero_buffer - Zero-out a part of a SG list + * @sgl: The SG list + * @nents: Number of SG entries + * @buflen: The number of bytes to zero out + * @skip: Number of bytes to skip before zeroing + * + * Returns the number of bytes zeroed. + **/ +static inline size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, + size_t buflen, off_t skip) +{ + return sgl_memset(sgl, nents, skip, 0, buflen); +} + /* * Maximum number of entries that will be allocated in one piece, if * a list larger than this is required then chaining will be utilized. diff --git a/lib/scatterlist.c b/lib/scatterlist.c index e3182de753d0..7e6acc67e9f6 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -1023,41 +1023,6 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, } EXPORT_SYMBOL(sg_pcopy_to_buffer); -/** - * sg_zero_buffer - Zero-out a part of a SG list - * @sgl: The SG list - * @nents: Number of SG entries - * @buflen: The number of bytes to zero out - * @skip: Number of bytes to skip before zeroing - * - * Returns the number of bytes zeroed. - **/ -size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, - size_t buflen, off_t skip) -{ - unsigned int offset = 0; - struct sg_mapping_iter miter; - unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; - - sg_miter_start(&miter, sgl, nents, sg_flags); - - if (!sg_miter_skip(&miter, skip)) - return false; - - while (offset < buflen && sg_miter_next(&miter)) { - unsigned int len; - - len = min(miter.length, buflen - offset); - memset(miter.addr, 0, len); - - offset += len; - } - - sg_miter_stop(&miter); - return offset; -} -EXPORT_SYMBOL(sg_zero_buffer); - /** * sgl_copy_sgl - Copy over a destination sgl from a source sgl * @d_sgl: Destination sgl @@ -1240,3 +1205,47 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk return sgl_compare_sgl_idx(x_sgl, x_nents, x_skip, y_sgl, y_nents, y_skip, n_bytes, NULL); } EXPORT_SYMBOL(sgl_compare_sgl); + +/** + * sgl_memset - set byte 'val' up to n_bytes times on SG list + * @sgl: The SG list + * @nents: Number of SG entries in sgl + * @skip: Number of bytes to skip before starting + * @val: byte value to write to sgl + * @n_bytes: The (maximum) number of bytes to modify + * + * Returns: + * The number of bytes written. + * + * Notes: + * Stops writing if either sgl or n_bytes is exhausted. If n_bytes is + * set SIZE_MAX then val will be written to each byte until the end + * of sgl. + * + * The notes in sgl_copy_sgl() about large sgl_s _applies here as well. + * + **/ +size_t sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, + u8 val, size_t n_bytes) +{ + size_t offset = 0; + size_t len; + struct sg_mapping_iter miter; + + if (n_bytes == 0) + return 0; + sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC | SG_MITER_TO_SG); + if (!sg_miter_skip(&miter, skip)) + goto fini; + + while ((offset < n_bytes) && sg_miter_next(&miter)) { + len = min(miter.length, n_bytes - offset); + memset(miter.addr, val, len); + offset += len; + } +fini: + sg_miter_stop(&miter); + return offset; +} +EXPORT_SYMBOL(sgl_memset); +