From patchwork Mon Jul 29 02:37:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13744260 Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 063F97D3E4; Mon, 29 Jul 2024 02:44:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.175 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722221071; cv=none; b=qYQu0EuSVqsKkMCOL36ascQ1KVqNfimW+XHUHyAjpx+VzeaJlxPo/CgJk9Z7sX3mQuVhUFGx8G/AizKjRmIQFrIkyyuVWoz0qirNd2sjUQ4DgL+WUpUzt4epwzwNEQXFJMluJSdtTWBSoSIiGfBPssubWanozPPSXBZsYKZEERY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722221071; c=relaxed/simple; bh=inPPFHuZm+7fEeywe6ogK4qmICCbgmhVjJQRSqf84EE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=piqLF5HxNhUNxgLSvnoNxpsQNkNhmtZqIc1mly/CfgjOwKZCcvfJISr7xqfzL06JCMrgkEokFB9WYPYTGhLgHaOgJ1x70GKcEFBFVJcxQuxDSrQmAkQBXUOveLGILg0T1KmARnYveQtUg99z6MZPNcwLVRa0EpbNo5fVredT3lI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=OsEzvySQ; arc=none smtp.client-ip=209.85.215.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OsEzvySQ" Received: by mail-pg1-f175.google.com with SMTP id 41be03b00d2f7-7a18ba4143bso1665714a12.2; Sun, 28 Jul 2024 19:44:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722221069; x=1722825869; 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=hxss6iSMiIilMwCNJtHyPtBSL44EBghXiK4U5v9w5a8=; b=OsEzvySQuN3fS7XRL/Ygzejo/N3gmMq++hmmtpcNMVLxuiPE7Xub8vDlZKy7KUCFv2 ohCXK4DGYtz2SecqCa2sO2uVaI2ZRnXZl3NMXaxTr7c2Vdsj2vpe4UBH7Dt2Zn3rORSS 9cr9PKoWUaVJn0y6wqCkXdmJe2ODZ4ZpUNMFg9Z9tuPqrNFVVSQ6y8YdOWZk3cIWdKJR tK66Mkuv38CGWkeFv6f22B9WxB3GCnGefGD1fy5xoSiIv6iHZ87lxim4ZtSRStnsJXsz RTXm9F/aIiM/yBZHWkCMiW4vuSQ4L/8O20HXFdQ7DrtT6B1Hb+boPfFwJFBTXPYc6eOG IPNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722221069; x=1722825869; 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=hxss6iSMiIilMwCNJtHyPtBSL44EBghXiK4U5v9w5a8=; b=qE+O/B8DIvOY2TyURxTTslsKRT9SceYLbR/ILUfYCfe/BTirP1YnBfhul88tsZjBei c1C4xHWfoIBhvAJY64inr7Ll2fPKMoSd+zxX/FtBJkQoxK25NG8Z/nzdPd+vBJVLVu8g a/rJN2Aze4XDSGvo+pBVGXbPUP0Ch3EyuLfJmU3gnk+8FEqjvQiZDQKRoLuZniiwBhaL WiPhPikJQX3u4AXoAVWuaD36BvYbQVVBPUPc1uXD/8u5HlmIDq2w2mV5z4XqYGiEVdBV Jmc7pYvASi4ZNjzoVVR3BA9hhrM9UNRpx4+RxgaUWh0538VvvcLd2NUHepb9jA6EKLyz 2wLQ== X-Forwarded-Encrypted: i=1; AJvYcCWPQzfg8zN/OGOzz/n+IBdIFaavfOoR+skAzWWLQKLsmcvkgK+qpnpM5RyQHEL5dvEFUt2ZaI1n3xodQZ5Gwyyv5Sg/un49KRm1IGGezTz5SpFItpd0LZ6FZKYfrR7hkPok0m+Q3Sk9BU14giWzZu3GrcAihYy0Bw0fvoJlR57sDqcm/abqPibrQ3I3pWuuGsG6Z1PgJEB/RfF1+Opge2mNSTKfjS2OX7OzqrCgvmvQ5gcvvsuoomlb5znpHfI4l2v44Tlul7qNggpI8tNLW/LxgNzrYK2J/MtupoJi5xk7ZJEi20QlCl6BJipn/Iq5nAQBkKpGcA== X-Gm-Message-State: AOJu0YxZmZiLAT/XeIs0qknPAZn9FpEhQvR2oqSIrrbGXBtTL3Tm4jx1 1Hq18lktu+LvRWJyadPX3mvCkrYol3ICt6R0VHvIHno4L46I45fg X-Google-Smtp-Source: AGHT+IG7/eKYXg7QfYOb1CdYS0BMtkGw6Mkjs56lIRKp/S/546Q1z5Hj0Wkc3TWWQHawrwJ+z6MQVw== X-Received: by 2002:a05:6a20:1582:b0:1c4:c7ae:ecea with SMTP id adf61e73a8af0-1c4c7aeefb4mr1212793637.11.1722221069087; Sun, 28 Jul 2024 19:44:29 -0700 (PDT) Received: from localhost.localdomain ([223.104.210.31]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2cf28c55a38sm7332247a91.10.2024.07.28.19.40.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 28 Jul 2024 19:44:28 -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 v4 06/11] mm/util: Deduplicate code in {kstrdup,kstrndup,kmemdup_nul} Date: Mon, 29 Jul 2024 10:37:14 +0800 Message-Id: <20240729023719.1933-7-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) In-Reply-To: <20240729023719.1933-1-laoar.shao@gmail.com> References: <20240729023719.1933-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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 41c7875572ed..62a4686352b9 100644 --- a/mm/util.c +++ b/mm/util.c @@ -43,33 +43,40 @@ 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); /** @@ -104,19 +111,7 @@ 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); @@ -190,17 +185,7 @@ 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);