From nobody Wed Sep 17 14:08:03 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8E53C3DA78 for ; Mon, 19 Dec 2022 04:22:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231303AbiLSEWD (ORCPT ); Sun, 18 Dec 2022 23:22:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230061AbiLSEV6 (ORCPT ); Sun, 18 Dec 2022 23:21:58 -0500 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D1896355 for ; Sun, 18 Dec 2022 20:21:57 -0800 (PST) Received: by mail-pl1-x633.google.com with SMTP id g10so7825031plo.11 for ; Sun, 18 Dec 2022 20:21:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=GYOZHntsfq9Oqu0AIUyQ2czFdBjuydE+iWot/+A9tks=; b=fEja4+CjRKWn1HDf3oFuDpMNyY4ILeRfE6RyXf0N2LsVGmugFuW2LT6wBLvR6OZXw9 s7Ow9Tn4mA/gsew93EA7bvJIULnSNmtXKHha8fd4yKp0848Rnd2RaM+zozllRMJQGKiD YzpUJErUX5fuOJ9C3DrXLrszMo6EGkBz7qB/UlNLp9AMG39/IhkTewQMLspDIb/7h5YR Jh+wMWr03nP/1Ezja2nIjoDlOek8aBKBej7A59SoRbd8+UQhut9sop6owyMfWOr40tCg +AnnrBajRSBuPP66YlCcU8f/TvAO45u1pOkTX9gcECAFBg6CJ6JqAONJQqspnXEmodWF BHnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=GYOZHntsfq9Oqu0AIUyQ2czFdBjuydE+iWot/+A9tks=; b=pcjNS9e5KeB4JrI/3UXhAd4lkw9O0rnLcoFsdfBRxFVegPIfc8kUZOEGYlGBm6mEiZ r4zYIrHklGd8jGaogPz7NPgDWddQQniFIlCMBlaf8eMkZocxW995aIjwHt1xKycOGF6n U8cjZTgS5ACLUIi0kS7huXyxXHa1aJhuM4EghitQJPPvTrmd2fYvunr1NM/a4VenvPoX 37ELuMo9t7wfjieQ+r9WTl5iGytQRpjGr/8pk9UK+6VI7HQayQMXx9GBC4zmZWDwMXRt ldf1uBmeByS0BtfvidPR6C380bDBWRB5xvVceJn8stOCK9wGzGdS0xcn43lpXn3oo6ew 0jow== X-Gm-Message-State: AFqh2krpeB5e68hwBHu1lMIJ30y+flRZ1AvElFdnFNuRAfWWASdoHfal qwW/lP8EuAZ+7zFYRVda1Q== X-Google-Smtp-Source: AMrXdXsShbSg9tkRr9cAr4isOuGI/2MNiXO5pgVI8hqOMcUl02pgbWJV8ue4UcuPDHun13xdkKLxfA== X-Received: by 2002:a17:902:cf08:b0:191:282:5d6c with SMTP id i8-20020a170902cf0800b0019102825d6cmr14622492plg.61.1671423716287; Sun, 18 Dec 2022 20:21:56 -0800 (PST) Received: from localhost.localdomain ([144.214.0.6]) by smtp.gmail.com with ESMTPSA id t9-20020a170902e84900b001888cadf8f6sm5896615plg.49.2022.12.18.20.21.54 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sun, 18 Dec 2022 20:21:55 -0800 (PST) From: Hao Sun To: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Cc: daniel@iogearbox.net, Hao Sun Subject: [PATCH] mm: new primitive kvmemdup() Date: Mon, 19 Dec 2022 12:21:26 +0800 Message-Id: <20221219042126.3396-1-sunhao.th@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Similar to kmemdup(), but support large amount of bytes with kvmalloc() and does *not* guarantee that the result will be physically contiguous. Use only in cases where kvmalloc() is needed and free it with kvfree(). Suggested-by: Daniel Borkmann =20 Signed-off-by: Hao Sun --- This pattern has been used in several places and we're also going to do this[1], seems reasonable to add this so that bpf and in future others could make use of it. [1] https://lore.kernel.org/bpf/7d274284-0fcc-061c-582e-3dfb629c6a44@iogear= box.net/T/#t --- include/linux/string.h | 1 + mm/util.c | 24 +++++++++++++++++++++++- 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/include/linux/string.h b/include/linux/string.h index db28802ab0a6..c062c581a98b 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -177,6 +177,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc; extern const char *kstrdup_const(const char *s, gfp_t gfp); extern char *kstrndup(const char *s, size_t len, gfp_t gfp); extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_siz= e(2); +extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_si= ze(2); extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); =20 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); diff --git a/mm/util.c b/mm/util.c index b56c92fb910f..cec9327b27b4 100644 --- a/mm/util.c +++ b/mm/util.c @@ -120,7 +120,8 @@ EXPORT_SYMBOL(kstrndup); * @len: memory region length * @gfp: GFP mask to use * - * Return: newly allocated copy of @src or %NULL in case of error + * Return: newly allocated copy of @src or %NULL in case of error, + * result is physically contiguous. Use kfree() to free. */ void *kmemdup(const void *src, size_t len, gfp_t gfp) { @@ -133,6 +134,27 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) } EXPORT_SYMBOL(kmemdup); =20 +/** + * kvmemdup - duplicate region of memory + * + * @src: memory region to duplicate + * @len: memory region length + * @gfp: GFP mask to use + * + * Return: newly allocated copy of @src or %NULL in case of error, + * result may be not physically contiguous. Use kvfree() to free. + */ +void *kvmemdup(const void *src, size_t len, gfp_t gfp) +{ + void *p; + + p =3D kvmalloc(len, gfp); + if (p) + memcpy(p, src, len); + return p; +} +EXPORT_SYMBOL(kvmemdup); + /** * kmemdup_nul - Create a NUL-terminated string from unterminated data * @s: The data to stringify base-commit: f9ff5644bcc04221bae56f922122f2b7f5d24d62 --=20 2.39.0