From patchwork Sun Aug 4 07:56:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13752552 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3985EC3DA7F for ; Sun, 4 Aug 2024 07:58:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BA7A910E0A0; Sun, 4 Aug 2024 07:58:22 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="Jq/rr7Tx"; dkim-atps=neutral Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) by gabe.freedesktop.org (Postfix) with ESMTPS id 442A110E0A0 for ; Sun, 4 Aug 2024 07:58:21 +0000 (UTC) Received: by mail-pl1-f173.google.com with SMTP id d9443c01a7336-1fd69e44596so33007395ad.1 for ; Sun, 04 Aug 2024 00:58:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722758301; x=1723363101; darn=lists.freedesktop.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=bS0UkRamrVL5XCR4Rnj9cLPm9Cl+fEpiyHi/lwqSnvY=; b=Jq/rr7TxlxrNR0ucv8scxKPHIpEH2dUnNMdUsq/6ErJ7rpplt2IYtMw+K9aekprA9e m/kUW+x1atZYfik6H90y6y2pw/kmYzpS1urspaURcga5DmqR49h0cAlvecFokiP1mzcj oXqp+hxhBD0yezMbCkdcfJ0OeDZ3jaxcep+ud6zgOxrzD8cneZE4DFe7wOpbTZh6f69h G5Ca/SVy6KT9TUGRu7y4VkJfSI1PocJ52+OxlMCeosQyrVbsuw4RQRID4hNEYadHbSIf oJDBdJQb64rROnvUYqMK39zZUUACverOS5YPrWOw3FEKEwlgzEfX2VmNFSVYzjHwpmAa 6jig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722758301; x=1723363101; 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=bS0UkRamrVL5XCR4Rnj9cLPm9Cl+fEpiyHi/lwqSnvY=; b=Pv262d1QnfYeuUjdl6dMrY2tIXT3j60srEVLnhOSCOsSBJw8rZA0vYMKhZRsX2dj0U LFgv7fiNADSFi1qQYHVkaTgX7ZXIklB3+HcLRKcFidmZvAGJoINgYwprjU0yWzm1PO5B O+rJMIEzlr8f43oERuuTpC5XPnVZkFffnaP0/y65oDTHDEic5CX16g+M8SQytFjzPSxs 6JNBpjU+GfhPbGpLMdzhgxGJhkojQsl35x5yq3NqDznaxvWy3GqpDqxGWSLeOu9Skdf/ QRSTZJMz+CQ9IXzswBd0FFgzAmXGeA5sBuCQJc041agTh7DZF+xt7Z+sxZCF8+JWeapF hjwA== X-Forwarded-Encrypted: i=1; AJvYcCXH9rEOinFarfRKvl0E56YPyKLbnUMtFA622CkCO4ChqIUsDpXDyRglidk6dmO4XCe2Rd6VPX/zthQpWXsQpZ5nSNWcNRVasnkcEXySBqVc X-Gm-Message-State: AOJu0YzKRivY3VzbGnWbtX94R86kQHF7hHXR3oomB/6nYvIZVXubr26Z uyyABY3xAHnIhJi4EZmmJWx/gO2vmYu7vSHFUlfFzPA3p7LmTscY X-Google-Smtp-Source: AGHT+IEGtCQCVMnQCKfJ0+BIkhT35+DpDH9a54ylBrsi080HAExdi6zY8c1ZJxWy2ZwMLSFkL3dmww== X-Received: by 2002:a17:903:1cb:b0:1fd:7ff5:c673 with SMTP id d9443c01a7336-1ff523ef0dfmr156564885ad.2.1722758300691; Sun, 04 Aug 2024 00:58:20 -0700 (PDT) Received: from localhost.localdomain ([39.144.105.172]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1ff59178248sm46387605ad.202.2024.08.04.00.58.03 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 04 Aug 2024 00:58:20 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Yafang Shao , Simon Horman , Matthew Wilcox Subject: [PATCH v5 6/9] mm/util: Deduplicate code in {kstrdup, kstrndup, kmemdup_nul} Date: Sun, 4 Aug 2024 15:56:16 +0800 Message-Id: <20240804075619.20804-7-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20240804075619.20804-1-laoar.shao@gmail.com> References: <20240804075619.20804-1-laoar.shao@gmail.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" These three functions follow the same pattern. To deduplicate the code, let's introduce a common helper __kmemdup_nul(). Suggested-by: Andrew Morton Signed-off-by: Yafang Shao Cc: Simon Horman Cc: Matthew Wilcox --- mm/util.c | 67 +++++++++++++++++++++---------------------------------- 1 file changed, 26 insertions(+), 41 deletions(-) diff --git a/mm/util.c b/mm/util.c index 912d64ede234..2c5addabd6f7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -45,33 +45,40 @@ void kfree_const(const void *x) EXPORT_SYMBOL(kfree_const); /** - * kstrdup - allocate space for and copy an existing string - * @s: the string to duplicate + * __kmemdup_nul - Create a NUL-terminated string from @s, which might be unterminated. + * @s: The data to copy + * @len: The size of the data, including the null terminator * @gfp: the GFP mask used in the kmalloc() call when allocating memory * - * Return: newly allocated copy of @s or %NULL in case of error + * Return: newly allocated copy of @s with NUL-termination or %NULL in + * case of error */ -noinline -char *kstrdup(const char *s, gfp_t gfp) +static __always_inline char *__kmemdup_nul(const char *s, size_t len, gfp_t gfp) { - size_t len; char *buf; - if (!s) + buf = kmalloc_track_caller(len, gfp); + if (!buf) return NULL; - len = strlen(s) + 1; - buf = kmalloc_track_caller(len, gfp); - if (buf) { - memcpy(buf, s, len); - /* During memcpy(), the string might be updated to a new value, - * which could be longer than the string when strlen() is - * called. Therefore, we need to add a null termimator. - */ - buf[len - 1] = '\0'; - } + memcpy(buf, s, len); + /* Ensure the buf is always NUL-terminated, regardless of @s. */ + buf[len - 1] = '\0'; return buf; } + +/** + * kstrdup - allocate space for and copy an existing string + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Return: newly allocated copy of @s or %NULL in case of error + */ +noinline +char *kstrdup(const char *s, gfp_t gfp) +{ + return s ? __kmemdup_nul(s, strlen(s) + 1, gfp) : NULL; +} EXPORT_SYMBOL(kstrdup); /** @@ -106,19 +113,7 @@ EXPORT_SYMBOL(kstrdup_const); */ char *kstrndup(const char *s, size_t max, gfp_t gfp) { - size_t len; - char *buf; - - if (!s) - return NULL; - - len = strnlen(s, max); - buf = kmalloc_track_caller(len+1, gfp); - if (buf) { - memcpy(buf, s, len); - buf[len] = '\0'; - } - return buf; + return s ? __kmemdup_nul(s, strnlen(s, max) + 1, gfp) : NULL; } EXPORT_SYMBOL(kstrndup); @@ -192,17 +187,7 @@ EXPORT_SYMBOL(kvmemdup); */ char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) { - char *buf; - - if (!s) - return NULL; - - buf = kmalloc_track_caller(len + 1, gfp); - if (buf) { - memcpy(buf, s, len); - buf[len] = '\0'; - } - return buf; + return s ? __kmemdup_nul(s, len + 1, gfp) : NULL; } EXPORT_SYMBOL(kmemdup_nul);