From patchwork Mon Dec 20 13:31:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lad Prabhakar X-Patchwork-Id: 12687881 X-Patchwork-Delegate: pavel@denx.de 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 aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id AABD1C433EF for ; Mon, 20 Dec 2021 13:31:47 +0000 (UTC) Received: from relmlie5.idc.renesas.com (relmlie5.idc.renesas.com [210.160.252.171]) by mx.groups.io with SMTP id smtpd.web12.5174.1640007106704986866 for ; Mon, 20 Dec 2021 05:31:46 -0800 Authentication-Results: mx.groups.io; dkim=missing; spf=pass (domain: bp.renesas.com, ip: 210.160.252.171, mailfrom: prabhakar.mahadev-lad.rj@bp.renesas.com) X-IronPort-AV: E=Sophos;i="5.88,220,1635174000"; d="scan'208";a="104110946" Received: from unknown (HELO relmlir5.idc.renesas.com) ([10.200.68.151]) by relmlie5.idc.renesas.com with ESMTP; 20 Dec 2021 22:31:42 +0900 Received: from localhost.localdomain (unknown [10.226.36.204]) by relmlir5.idc.renesas.com (Postfix) with ESMTP id 68D3D4005E10; Mon, 20 Dec 2021 22:31:41 +0900 (JST) From: Lad Prabhakar To: cip-dev@lists.cip-project.org, Nobuhiro Iwamatsu , Pavel Machek Cc: Biju Das Subject: [PATCH 5.10.y-cip 01/22] mm: slab: provide krealloc_array() Date: Mon, 20 Dec 2021 13:31:18 +0000 Message-Id: <20211220133139.21624-2-prabhakar.mahadev-lad.rj@bp.renesas.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211220133139.21624-1-prabhakar.mahadev-lad.rj@bp.renesas.com> References: <20211220133139.21624-1-prabhakar.mahadev-lad.rj@bp.renesas.com> List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Mon, 20 Dec 2021 13:31:47 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/7199 From: Bartosz Golaszewski commit f0dbd2bd1c22c6670e83ddcd46a9beb8b575e86d upstream. When allocating an array of elements, users should check for multiplication overflow or preferably use one of the provided helpers like: kmalloc_array(). There's no krealloc_array() counterpart but there are many users who use regular krealloc() to reallocate arrays. Let's provide an actual krealloc_array() implementation. While at it: add some documentation regarding krealloc. Link: https://lkml.kernel.org/r/20201109110654.12547-3-brgl@bgdev.pl Signed-off-by: Bartosz Golaszewski Acked-by: Vlastimil Babka Cc: Alexander Shishkin Cc: Andy Shevchenko Cc: Borislav Petkov Cc: Borislav Petkov Cc: Christian Knig Cc: Christoph Lameter Cc: Daniel Vetter Cc: Daniel Vetter Cc: David Airlie Cc: David Rientjes Cc: Gustavo Padovan Cc: James Morse Cc: Jaroslav Kysela Cc: Jason Wang Cc: Joonsoo Kim Cc: Linus Walleij Cc: Maarten Lankhorst Cc: Mauro Carvalho Chehab Cc: Maxime Ripard Cc: "Michael S . Tsirkin" Cc: Pekka Enberg Cc: Robert Richter Cc: Sumit Semwal Cc: Takashi Iwai Cc: Takashi Iwai Cc: Thomas Zimmermann Cc: Tony Luck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Lad Prabhakar --- Documentation/core-api/memory-allocation.rst | 4 ++++ include/linux/slab.h | 18 ++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst index 4446a1ac36cc..5954ddf6ee13 100644 --- a/Documentation/core-api/memory-allocation.rst +++ b/Documentation/core-api/memory-allocation.rst @@ -147,6 +147,10 @@ The address of a chunk allocated with `kmalloc` is aligned to at least ARCH_KMALLOC_MINALIGN bytes. For sizes which are a power of two, the alignment is also guaranteed to be at least the respective size. +Chunks allocated with kmalloc() can be resized with krealloc(). Similarly +to kmalloc_array(): a helper for resizing arrays is provided in the form of +krealloc_array(). + For large allocations you can use vmalloc() and vzalloc(), or directly request pages from the page allocator. The memory allocated by `vmalloc` and related functions is not physically contiguous. diff --git a/include/linux/slab.h b/include/linux/slab.h index dd6897f62010..be4ba5867ac5 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -592,6 +592,24 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) return __kmalloc(bytes, flags); } +/** + * krealloc_array - reallocate memory for an array. + * @p: pointer to the memory chunk to reallocate + * @new_n: new number of elements to alloc + * @new_size: new size of a single member of the array + * @flags: the type of memory to allocate (see kmalloc) + */ +static __must_check inline void * +krealloc_array(void *p, size_t new_n, size_t new_size, gfp_t flags) +{ + size_t bytes; + + if (unlikely(check_mul_overflow(new_n, new_size, &bytes))) + return NULL; + + return krealloc(p, bytes, flags); +} + /** * kcalloc - allocate memory for an array. The memory is set to zero. * @n: number of elements.