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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 76EBFC43461 for ; Tue, 8 Sep 2020 19:02:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20EE320757 for ; Tue, 8 Sep 2020 19:02:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599591748; bh=1/B2Nlfy+gnWful87HjQ5P9kzGx/+jtgEH5HlRcJhUM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=j7X211A7BZu+3hOn8cmsuh2ewGg80VzN36swx6KzDkcrPFYVByIs9jVXZLM0ENgh5 lVTEHopoPu+MtAzvMVI/E/FqQqOidxapGX7Ytx4jAS4NLZu/KSSPCvsi2P1mVQGHry drCLRb58/LVW8w9C/5S4QMdQDhfTgtsJ9iw9ZLRM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731595AbgIHTCA (ORCPT ); Tue, 8 Sep 2020 15:02:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:55072 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731293AbgIHQIC (ORCPT ); Tue, 8 Sep 2020 12:08:02 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1D59B23E56; Tue, 8 Sep 2020 15:47:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599580057; bh=1/B2Nlfy+gnWful87HjQ5P9kzGx/+jtgEH5HlRcJhUM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=biK2xbuL9A6kjDinANH30khfzTRzDPB+bz4o6wSXAPZLck6domfJ5YNR4tWnZkI0M b/em2RKZ1YqdASFsTO7SLCZGKoIZOxHJKVyL6j00RyK87xXOEorGUfqEAIvdry+gZP l55HXlaUu41pVCddgfhnSE8vVTMgkYjbJD3ZlB0o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, JiangYu , Daniel Meyerholt , Mike Christie , Bodo Stroesser , "Martin K. Petersen" Subject: [PATCH 4.19 05/88] scsi: target: tcmu: Optimize use of flush_dcache_page Date: Tue, 8 Sep 2020 17:25:06 +0200 Message-Id: <20200908152221.351964351@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200908152221.082184905@linuxfoundation.org> References: <20200908152221.082184905@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bodo Stroesser commit 3c58f737231e2c8cbf543a09d84d8c8e80e05e43 upstream. (scatter|gather)_data_area() need to flush dcache after writing data to or before reading data from a page in uio data area. The two routines are able to handle data transfer to/from such a page in fragments and flush the cache after each fragment was copied by calling the wrapper tcmu_flush_dcache_range(). That means: 1) flush_dcache_page() can be called multiple times for the same page. 2) Calling flush_dcache_page() indirectly using the wrapper does not make sense, because each call of the wrapper is for one single page only and the calling routine already has the correct page pointer. Change (scatter|gather)_data_area() such that, instead of calling tcmu_flush_dcache_range() before/after each memcpy, it now calls flush_dcache_page() before unmapping a page (when writing is complete for that page) or after mapping a page (when starting to read the page). After this change only calls to tcmu_flush_dcache_range() for addresses in vmalloc'ed command ring are left over. The patch was tested on ARM with kernel 4.19.118 and 5.7.2 Link: https://lore.kernel.org/r/20200618131632.32748-2-bstroesser@ts.fujitsu.com Tested-by: JiangYu Tested-by: Daniel Meyerholt Acked-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/target/target_core_user.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -687,8 +687,10 @@ static void scatter_data_area(struct tcm from = kmap_atomic(sg_page(sg)) + sg->offset; while (sg_remaining > 0) { if (block_remaining == 0) { - if (to) + if (to) { + flush_dcache_page(page); kunmap_atomic(to); + } block_remaining = DATA_BLOCK_SIZE; dbi = tcmu_cmd_get_dbi(tcmu_cmd); @@ -733,7 +735,6 @@ static void scatter_data_area(struct tcm memcpy(to + offset, from + sg->length - sg_remaining, copy_bytes); - tcmu_flush_dcache_range(to, copy_bytes); } sg_remaining -= copy_bytes; @@ -742,8 +743,10 @@ static void scatter_data_area(struct tcm kunmap_atomic(from - sg->offset); } - if (to) + if (to) { + flush_dcache_page(page); kunmap_atomic(to); + } } static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd, @@ -789,13 +792,13 @@ static void gather_data_area(struct tcmu dbi = tcmu_cmd_get_dbi(cmd); page = tcmu_get_block_page(udev, dbi); from = kmap_atomic(page); + flush_dcache_page(page); } copy_bytes = min_t(size_t, sg_remaining, block_remaining); if (read_len < copy_bytes) copy_bytes = read_len; offset = DATA_BLOCK_SIZE - block_remaining; - tcmu_flush_dcache_range(from, copy_bytes); memcpy(to + sg->length - sg_remaining, from + offset, copy_bytes);