realloc(): struct sys_mem_pool_block is word aligned

Since commit 39cd2ebef7 ("malloc: make sure returned memory is
properly aligned") the size of struct sys_mem_pool_block size is
rounded up to the next word boundary.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

lib/libc/minimal/source/stdlib/malloc.c

@@ -88,6 +88,7 @@ void *calloc(size_t nmemb, size_t size)
 void *realloc(void *ptr, size_t requested_size)
 {
 	struct sys_mem_pool_block *blk;
+	size_t struct_blk_size = WB_UP(sizeof(struct sys_mem_pool_block));
 	size_t block_size, total_requested_size;
 	void *new_ptr;
 
@@ -101,7 +102,7 @@ void *realloc(void *ptr, size_t requested_size)
 	}
 
 	/* Stored right before the pointer passed to the user */
-	blk = (struct sys_mem_pool_block *)((char *)ptr - sizeof(*blk));
+	blk = (struct sys_mem_pool_block *)((char *)ptr - struct_blk_size);
 
 	/* Determine size of previously allocated block by its level.
 	 * Most likely a bit larger than the original allocation
@@ -112,8 +113,7 @@ void *realloc(void *ptr, size_t requested_size)
 	}
 
 	/* We really need this much memory */
-	total_requested_size = requested_size +
-		sizeof(struct sys_mem_pool_block);
+	total_requested_size = requested_size + struct_blk_size;
 
 	if (block_size >= total_requested_size) {
 		/* Existing block large enough, nothing to do */
@@ -125,7 +125,7 @@ void *realloc(void *ptr, size_t requested_size)
 		return NULL;
 	}
 
-	memcpy(new_ptr, ptr, block_size - sizeof(struct sys_mem_pool_block));
+	memcpy(new_ptr, ptr, block_size - struct_blk_size);
 	free(ptr);
 
 	return new_ptr;