slab: introduce krealloc
This introduce krealloc() that reallocates memory while keeping the contents
unchanged. The allocator avoids reallocation if the new size fits the
currently used cache. I also added a simple non-optimized version for
mm/slob.c for compatibility.
[akpm@linux-foundation.org: fix warnings]
Acked-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slob.c b/mm/slob.c
index 5adc29c..03cce3d 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -190,6 +190,39 @@
}
EXPORT_SYMBOL(__kmalloc);
+/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ *
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes. If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc(). If @size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ void *ret;
+
+ if (unlikely(!p))
+ return kmalloc_track_caller(new_size, flags);
+
+ if (unlikely(!new_size)) {
+ kfree(p);
+ return NULL;
+ }
+
+ ret = kmalloc_track_caller(new_size, flags);
+ if (ret) {
+ memcpy(ret, p, min(new_size, ksize(p)));
+ kfree(p);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(krealloc);
+
void kfree(const void *block)
{
bigblock_t *bb, **last = &bigblocks;
@@ -219,7 +252,7 @@
EXPORT_SYMBOL(kfree);
-unsigned int ksize(const void *block)
+size_t ksize(const void *block)
{
bigblock_t *bb;
unsigned long flags;