From patchwork Fri Oct 13 12:22:36 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: 734047 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 4F81015E86 for ; Fri, 13 Oct 2023 12:22:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aMPVCWPL" Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5124BF; Fri, 13 Oct 2023 05:22:44 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id d9443c01a7336-1c746bc3bceso5602485ad.1; Fri, 13 Oct 2023 05:22:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697199764; x=1697804564; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2zx15p0SmnRH09BE0u4PUAnqk7+Zw8rJ36gokTY/TP8=; b=aMPVCWPLUm/yNcUul5Bcwo/D6XX9JAaqJKITX2A6quJxheuplRVWCdHO6GwLzoj4Xr 5pC1OM5VTzufH80nfta7x7nbuXJpY95i+huY6UeFDFLk+tpLlyjleOfFQ3/8jjSeYixu hKGjdA3GRLNYNQ/ya3hfxCJ9z3lOHORW/GMNVjX3JuVw07EC3fBlr0k5aV0YpyJuYaZj oU8mu2yrgJwqD7mNyDoD29hTV2OALYYGRa/aq+yjW0nwOvqQ9TdbbpMYrSpjbX4uFg4h BWwLYT6+oEIjYM7Prsd2I1xptclx/1SoI0lnrg1B3ANAWFPCEsiKC12Rg3UMRTm7whz1 /1eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697199764; x=1697804564; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2zx15p0SmnRH09BE0u4PUAnqk7+Zw8rJ36gokTY/TP8=; b=eh7et56HpvsJKViGmKR+QCVm6aC9tKGovQV2QZQnDIfj2OZW6NxZ/W+MpuqW28grhK b/gq7cvHSYyn4WiBmpxiyYyy40IaPTRTwh+PCHG6K6hSHBg0+U+hOt6b+LAq0d31xTyz kqBkKt3xAyk5acs6WJX8KmA5aarkNZ6hsGzVIpx3NyQQBSxNLoqJaBJplXrUiUd9qvmk H1hAsNM9vOdMzfXiB1XkQwPbpJr+pFRwnhMo7c8roaTt7Azqt09HNxlFfmkGsgeRuRwK fDqnB9wO1zVYAJAel5Ct+eaqbgOinwDU9M7Jz0AGPpym3K1VMABDo0l1PNIL1vIItRin 1Mrw== X-Gm-Message-State: AOJu0Yyy4IQR16RhsA8WR+BRxz7MzYGzyRjtOzn2eVVHP+2TekyN1p2y 3B1Ie9/7KVsDRtKRf4/3NhM= X-Google-Smtp-Source: AGHT+IGjkU4JcHIHWn7TBKy/+945CIIvrTtnhePZe+9GlhF00RheFqtdVD3cHO93AVyexdwWn60ibQ== X-Received: by 2002:a05:6a20:4407:b0:133:6e3d:68cd with SMTP id ce7-20020a056a20440700b001336e3d68cdmr36263214pzb.3.1697199764020; Fri, 13 Oct 2023 05:22:44 -0700 (PDT) Received: from localhost.localdomain ([140.116.154.65]) by smtp.gmail.com with ESMTPSA id jd22-20020a170903261600b001bc930d4517sm3781802plb.42.2023.10.13.05.22.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Oct 2023 05:22:43 -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 v2] ACPI: NFIT: Optimize nfit_mem_cmp() for efficiency Date: Fri, 13 Oct 2023 20:22:36 +0800 Message-Id: <20231013122236.2127269-1-visitorckw@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231012215903.2104652-1-visitorckw@gmail.com> References: <20231012215903.2104652-1-visitorckw@gmail.com> 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 --- v1 -> v2: - Add explicit type cast in case the sizes of u32 and int differ. 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..563a32eba888 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 (int)handleA - (int)handleB; } static int nfit_mem_init(struct acpi_nfit_desc *acpi_desc)