From: Bartosz Golaszewski <brgl@bgdev•pl>
To: "Andy Shevchenko" <andriy.shevchenko@linux•intel.com>,
"Sumit Semwal" <sumit.semwal@linaro•org>,
"Gustavo Padovan" <gustavo@padovan•org>,
"Christian König" <christian.koenig@amd•com>,
"Mauro Carvalho Chehab" <mchehab@kernel•org>,
"Borislav Petkov" <bp@alien8•de>,
"Tony Luck" <tony.luck@intel•com>,
"James Morse" <james.morse@arm•com>,
"Robert Richter" <rric@kernel•org>,
"Maarten Lankhorst" <maarten.lankhorst@linux•intel.com>,
"Maxime Ripard" <mripard@kernel•org>,
"Thomas Zimmermann" <tzimmermann@suse•de>,
"David Airlie" <airlied@linux•ie>,
"Daniel Vetter" <daniel@ffwll•ch>,
"Alexander Shishkin" <alexander.shishkin@linux•intel.com>,
"Linus Walleij" <linus.walleij@linaro•org>,
"Michael S . Tsirkin" <mst@redhat•com>,
"Jason Wang" <jasowang@redhat•com>,
"Christoph Lameter" <cl@linux•com>,
"Pekka Enberg" <penberg@kernel•org>,
"David Rientjes" <rientjes@google•com>,
"Joonsoo Kim" <iamjoonsoo.kim@lge•com>,
"Andrew Morton" <akpm@linux-foundation•org>,
"Jaroslav Kysela" <perex@perex•cz>,
"Takashi Iwai" <tiwai@suse•com>
Cc: linux-media@vger•kernel.org, dri-devel@lists•freedesktop.org,
linaro-mm-sig@lists•linaro.org, linux-kernel@vger•kernel.org,
linux-edac@vger•kernel.org, linux-gpio@vger•kernel.org,
kvm@vger•kernel.org, virtualization@lists•linux-foundation.org,
netdev@vger•kernel.org, linux-mm@kvack•org,
alsa-devel@alsa-project•org,
Bartosz Golaszewski <bgolaszewski@baylibre•com>,
Vlastimil Babka <vbabka@suse•cz>
Subject: [PATCH v2 1/8] mm: slab: provide krealloc_array()
Date: Mon, 2 Nov 2020 16:20:30 +0100 [thread overview]
Message-ID: <20201102152037.963-2-brgl@bgdev.pl> (raw)
In-Reply-To: <20201102152037.963-1-brgl@bgdev.pl>
From: Bartosz Golaszewski <bgolaszewski@baylibre•com>
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.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre•com>
Acked-by: Vlastimil Babka <vbabka@suse•cz>
---
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..6dc38b40439a 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 resising 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.
--
2.29.1
next prev parent reply other threads:[~2020-11-02 15:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-02 15:20 [PATCH v2 0/8] slab: provide and use krealloc_array() Bartosz Golaszewski
2020-11-02 15:20 ` Bartosz Golaszewski [this message]
2020-11-02 15:41 ` [PATCH v2 1/8] mm: slab: provide krealloc_array() Matthew Wilcox
2020-11-02 15:43 ` Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 2/8] ALSA: pcm: use krealloc_array() Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 3/8] vhost: vringh: " Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 4/8] pinctrl: " Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 5/8] edac: ghes: " Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 6/8] drm: atomic: " Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 7/8] hwtracing: intel: " Bartosz Golaszewski
2020-11-02 15:20 ` [PATCH v2 8/8] dma-buf: " Bartosz Golaszewski
2020-11-02 16:10 ` Andy Shevchenko
2020-11-03 4:14 ` [PATCH v2 0/8] slab: provide and " Joe Perches
2020-11-03 10:12 ` Bartosz Golaszewski
2020-11-03 10:55 ` Andy Shevchenko
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