From patchwork Fri Oct 16 04:52:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 11840869 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1FF151984 for ; Fri, 16 Oct 2020 04:53:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0AF532073A for ; Fri, 16 Oct 2020 04:53:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388665AbgJPExU (ORCPT ); Fri, 16 Oct 2020 00:53:20 -0400 Received: from smtp.infotech.no ([82.134.31.41]:44940 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388345AbgJPExK (ORCPT ); Fri, 16 Oct 2020 00:53:10 -0400 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id B2F60204238; Fri, 16 Oct 2020 06:53:08 +0200 (CEST) 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 l6GpIUqz6pps; Fri, 16 Oct 2020 06:53:07 +0200 (CEST) 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 9A707204259; Fri, 16 Oct 2020 06:53:05 +0200 (CEST) From: Douglas Gilbert To: linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Cc: martin.petersen@oracle.com, axboe@kernel.dk, bvanassche@acm.org Subject: [PATCH 4/4] scatterlist: add sgl_memset() Date: Fri, 16 Oct 2020 00:52:58 -0400 Message-Id: <20201016045258.16246-5-dgilbert@interlog.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201016045258.16246-1-dgilbert@interlog.com> References: <20201016045258.16246-1-dgilbert@interlog.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@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. Signed-off-by: Douglas Gilbert --- include/linux/scatterlist.h | 3 +++ lib/scatterlist.c | 39 +++++++++++++++++++++++++++++++++++-- 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ae260dc5fedb..e50dc9a6d887 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -329,6 +329,9 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, size_t n_bytes); +void sgl_memset(struct scatterlist *sgl, unsigned int nents, off_t skip, + u8 val, size_t n_bytes); + /* * 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 344725990b9d..3ca66f0c949f 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -1083,8 +1083,8 @@ EXPORT_SYMBOL(sgl_copy_sgl); * **/ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_skip, - struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, - size_t n_bytes) + struct scatterlist *y_sgl, unsigned int y_nents, off_t y_skip, + size_t n_bytes) { bool equ = true; size_t x_off, y_off, len, x_len, y_len; @@ -1140,3 +1140,38 @@ bool sgl_compare_sgl(struct scatterlist *x_sgl, unsigned int x_nents, off_t x_sk return equ; } EXPORT_SYMBOL(sgl_compare_sgl); + +/** + * sgl_memset - set byte 'val' 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 number of bytes to modify + * + * Notes: + * Writes val n_bytes times or until sgl is exhausted. + * + **/ +void 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; + unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG; + + if (n_bytes == 0) + return; + sg_miter_start(&miter, sgl, nents, sg_flags); + 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); +}