devres: Fix devm_krealloc() wasting memory

Driver API devm_krealloc() calls alloc_dr() with wrong argument
@total_new_size, so causes more memory to be allocated than required
fix this memory waste by using @new_size as the argument for alloc_dr().

Fixes: f824857 ("devres: provide devm_krealloc()")
Cc: [email protected]
Signed-off-by: Zijun Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: zijun-hu

drivers/base/devres.c

@@ -896,9 +896,12 @@ void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp)
 	/*
 	 * Otherwise: allocate new, larger chunk. We need to allocate before
 	 * taking the lock as most probably the caller uses GFP_KERNEL.
+	 * alloc_dr() will call check_dr_size() to reserve extra memory
+	 * for struct devres automatically, so size @new_size user request
+	 * is delivered to it directly as devm_kmalloc() does.
 	 */
 	new_dr = alloc_dr(devm_kmalloc_release,
-			  total_new_size, gfp, dev_to_node(dev));
+			  new_size, gfp, dev_to_node(dev));
 	if (!new_dr)
 		return NULL;