include: kernel: add the container_of.h file

Add the container_of.h file that defines the container_of macro. This
macro allows the kernel to get the parent struct of a pointer with an
offset.

Signed-off-by: Danny Holman <dholman@gymli.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/kernel/container_of.h b/include/kernel/container_of.h
new file mode 100644
index 0000000..1b5b444
--- /dev/null
+++ b/include/kernel/container_of.h
@@ -0,0 +1,10 @@
+#ifndef KERNEL_CONTAINER_OF_H
+#define KERNEL_CONTAINER_OF_H
+
+#ifndef container_of
+#define container_of(ptr, type, member) ({                              \
+                const typeof(((type*)0)->member)*__mptr = (ptr);        \
+                (type*)((char*)__mptr - offsetof(type, member)); })
+#endif
+
+#endif