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

Message ID 20201027121725.24660-2-brgl@bgdev.pl
State New
Headers show
Series slab: provide and use krealloc_array() | expand

Commit Message

Bartosz Golaszewski Oct. 27, 2020, 12:17 p.m. UTC 
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.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 include/linux/slab.h | 11 +++++++++++
 1 file changed, 11 insertions(+)
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Patch

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.