Re: [PATCH 1/8] mm: slab: provide krealloc_array()

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On 10/27/20 1:17 PM, Bartosz Golaszewski wrote:
From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

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.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

Makes sense.
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

---
  include/linux/slab.h | 11 +++++++++++
  1 file changed, 11 insertions(+)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index dd6897f62010..0e6683affee7 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -592,6 +592,17 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
  	return __kmalloc(bytes, flags);
  }
+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.





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