From patchwork Thu Oct 12 21:59:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuan-Wei Chiu X-Patchwork-Id: 733404 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 D21BE3FB21 for ; Thu, 12 Oct 2023 21:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VIA+h5/n" Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 948D2DA; Thu, 12 Oct 2023 14:59:11 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id d9443c01a7336-1c746bc3bceso3979785ad.1; Thu, 12 Oct 2023 14:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697147951; x=1697752751; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=2bRmsNjujjr87IHjRkMLVF3EP+IER+0qQMW+fpMjLQg=; b=VIA+h5/nZoHUgD3AI0UixqdM6pdd0yjw+UrdxuWekL0/bcwmZ23iPlB9eqHKjSnaiG jfzk1dzBbMVlk+yPvOeNcIO24a0vk949cizdDQQNArl/PIECN3RzFLf5JCQzTid/yV5l gCccI8QiVoTUD8QJXp/wkXR4Viv6qCRX25t1ySGGQNU+UCq21aDwisgvpZBLgdqdZHtn eaUNNpD+2/IY+0oijDHQHnDR3715FoMUor5dcTA5Tboucb14xFR0b2rvJ3rg4nk9Eg2e DNcfNuJ1tDFXEkcqL71fMk9YtfSUsN2PJ/bIZVwqWCWRBvhwscge1WQYBcpynHkHwtwc V+Jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697147951; x=1697752751; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=2bRmsNjujjr87IHjRkMLVF3EP+IER+0qQMW+fpMjLQg=; b=OHoPGrSN+5tg87wabtpV71E9/i41dKVixVarFHCLkpCZHW5ATsA6kC1yVutKahfsHN 9xXB122fqQulj0qLH1jfpLoCucme/fI+dYsBU3NVTc7gqcZET2NDos71fUsoO+Glik5Q xkuR8Huw8x67nS8KspDTOavEiNgvC5MTFFZf5HT/+ZfTXfYHhrtWpfiYw55eh0C1Pa35 CcrQ4mDgH4/tvCQk6rqwwZxxYcYE2qPIF9kw7yDJdyMkGdfTufGrZ4dDBpKY5ndPqCCk a5Vrv7p/gfrG58g/W0rKMLVZlC5GiSUw1Xe5OVeUduzcsHlnuqJbb4EyWK6RQg4xAvc8 hcBw== X-Gm-Message-State: AOJu0YxE3+sz5Z0jFURgvXRfhQ1qHdqTBJRHpY/7utDraomOVqqzBfWV crJ1J21zwe4R9QTMK0n0vqE= X-Google-Smtp-Source: AGHT+IEJ5AnfE0+n1T0JHCM+RVwVG1qkIZvLRGfH9TlJVR5npNnpa4dd1sYhMzJW9LCyM0so1ZGDLw== X-Received: by 2002:a17:90a:9f83:b0:27c:fbf8:6c43 with SMTP id o3-20020a17090a9f8300b0027cfbf86c43mr7314082pjp.1.1697147950948; Thu, 12 Oct 2023 14:59:10 -0700 (PDT) Received: from localhost.localdomain ([140.116.154.65]) by smtp.gmail.com with ESMTPSA id 5-20020a17090a198500b0027768125e24sm2489295pji.39.2023.10.12.14.59.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Oct 2023 14:59:10 -0700 (PDT) From: Kuan-Wei Chiu To: dan.j.williams@intel.com, vishal.l.verma@intel.com, dave.jiang@intel.com, ira.weiny@intel.com Cc: rafael@kernel.org, lenb@kernel.org, nvdimm@lists.linux.dev, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Kuan-Wei Chiu Subject: [PATCH] ACPI: NFIT: Optimize nfit_mem_cmp() for efficiency Date: Fri, 13 Oct 2023 05:59:03 +0800 Message-Id: <20231012215903.2104652-1-visitorckw@gmail.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net The original code used conditional branching in the nfit_mem_cmp function to compare two values and return -1, 1, or 0 based on the result. However, the list_sort comparison function only needs results <0, >0, or =0. This patch optimizes the code to make the comparison branchless, improving efficiency and reducing code size. This change reduces the number of comparison operations from 1-2 to a single subtraction operation, thereby saving the number of instructions. Signed-off-by: Kuan-Wei Chiu --- drivers/acpi/nfit/core.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index f96bf32cd368..eea827d9af08 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -1138,11 +1138,7 @@ static int nfit_mem_cmp(void *priv, const struct list_head *_a, handleA = __to_nfit_memdev(a)->device_handle; handleB = __to_nfit_memdev(b)->device_handle; - if (handleA < handleB) - return -1; - else if (handleA > handleB) - return 1; - return 0; + return handleA - handleB; } static int nfit_mem_init(struct acpi_nfit_desc *acpi_desc)