mm: slab: provide krealloc_array()
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 <bgolaszewski@baylibre.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Christian Knig <christian.koenig@amd.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: David Rientjes <rientjes@google.com> Cc: Gustavo Padovan <gustavo@padovan.org> Cc: James Morse <james.morse@arm.com> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Jason Wang <jasowang@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Maxime Ripard <mripard@kernel.org> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Robert Richter <rric@kernel.org> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Takashi Iwai <tiwai@suse.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -147,6 +147,10 @@ The address of a chunk allocated with `kmalloc` is aligned to at least
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ARCH_KMALLOC_MINALIGN bytes. For sizes which are a power of two, the
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alignment is also guaranteed to be at least the respective size.
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Chunks allocated with kmalloc() can be resized with krealloc(). Similarly
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to kmalloc_array(): a helper for resizing arrays is provided in the form of
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krealloc_array().
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For large allocations you can use vmalloc() and vzalloc(), or directly
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request pages from the page allocator. The memory allocated by `vmalloc`
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and related functions is not physically contiguous.
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@ -592,6 +592,24 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
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return __kmalloc(bytes, flags);
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}
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/**
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* krealloc_array - reallocate memory for an array.
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* @p: pointer to the memory chunk to reallocate
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* @new_n: new number of elements to alloc
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* @new_size: new size of a single member of the array
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* @flags: the type of memory to allocate (see kmalloc)
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*/
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static __must_check inline void *
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krealloc_array(void *p, size_t new_n, size_t new_size, gfp_t flags)
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{
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size_t bytes;
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if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
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return NULL;
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return krealloc(p, bytes, flags);
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}
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/**
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* kcalloc - allocate memory for an array. The memory is set to zero.
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* @n: number of elements.
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