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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 v3 2/9] mm: slab: provide krealloc_array()
Date: Mon,  9 Nov 2020 12:06:47 +0100	[thread overview]
Message-ID: <20201109110654.12547-3-brgl@bgdev.pl> (raw)
In-Reply-To: <20201109110654.12547-1-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..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.
-- 
2.29.1


WARNING: multiple messages have this Message-ID
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: alsa-devel@alsa-project.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	virtualization@lists.linux-foundation.org,
	linaro-mm-sig@lists.linaro.org, linux-gpio@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	linux-media@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	linux-edac@vger.kernel.org
Subject: [PATCH v3 2/9] mm: slab: provide krealloc_array()
Date: Mon,  9 Nov 2020 12:06:47 +0100	[thread overview]
Message-ID: <20201109110654.12547-3-brgl@bgdev.pl> (raw)
In-Reply-To: <20201109110654.12547-1-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..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.
-- 
2.29.1


WARNING: multiple messages have this Message-ID
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: alsa-devel@alsa-project.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	virtualization@lists.linux-foundation.org,
	linaro-mm-sig@lists.linaro.org, linux-gpio@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	linux-media@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	linux-edac@vger.kernel.org
Subject: [PATCH v3 2/9] mm: slab: provide krealloc_array()
Date: Mon,  9 Nov 2020 12:06:47 +0100	[thread overview]
Message-ID: <20201109110654.12547-3-brgl@bgdev.pl> (raw)
In-Reply-To: <20201109110654.12547-1-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..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.
-- 
2.29.1

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  parent reply	other threads:[~2020-11-09 11:08 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 11:06 [PATCH v3 0/9] slab: provide and use krealloc_array() Bartosz Golaszewski
2020-11-09 11:06 ` Bartosz Golaszewski
2020-11-09 11:06 ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 1/9] mm: slab: clarify krealloc()'s behavior with __GFP_ZERO Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` Bartosz Golaszewski [this message]
2020-11-09 11:06   ` [PATCH v3 2/9] mm: slab: provide krealloc_array() Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 3/9] ALSA: pcm: use krealloc_array() Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 4/9] vhost: vringh: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 5/9] pinctrl: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-10 14:48   ` Linus Walleij
2020-11-10 14:48     ` Linus Walleij
2020-11-10 14:48     ` Linus Walleij
2020-11-10 14:48     ` Linus Walleij
2020-11-09 11:06 ` [PATCH v3 6/9] edac: ghes: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 7/9] drm: atomic: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 8/9] hwtracing: intel: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06 ` [PATCH v3 9/9] dma-buf: " Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski
2020-11-09 11:06   ` Bartosz Golaszewski

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