move Rust sources to top level, C sources into c_src

[bcachefs-tools-debian] / c_src / include / linux / err.h

diff --git a/c_src/include/linux/err.h b/c_src/include/linux/err.h
new file mode 100644 (file)
index 0000000..e94bdff
--- /dev/null
+++ b/c_src/include/linux/err.h
@@ -0,0 +1,68 @@
+#ifndef __TOOLS_LINUX_ERR_H
+#define __TOOLS_LINUX_ERR_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+#include <asm/errno.h>
+
+/*
+ * Original kernel header comment:
+ *
+ * Kernel pointers have redundant information, so we can use a
+ * scheme where we can return either an error code or a normal
+ * pointer with the same return value.
+ *
+ * This should be a per-architecture thing, to allow different
+ * error and pointer decisions.
+ *
+ * Userspace note:
+ * The same principle works for userspace, because 'error' pointers
+ * fall down to the unused hole far from user space, as described
+ * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
+ *
+ * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
+ * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
+ *
+ * It should be the same case for other architectures, because
+ * this code is used in generic kernel code.
+ */
+#define MAX_ERRNO      4095
+
+#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
+
+static inline void * __must_check ERR_PTR(long error_)
+{
+       return (void *) error_;
+}
+
+static inline long __must_check PTR_ERR(__force const void *ptr)
+{
+       return (long) ptr;
+}
+
+static inline bool __must_check IS_ERR(__force const void *ptr)
+{
+       return IS_ERR_VALUE((unsigned long)ptr);
+}
+
+static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
+{
+       return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
+}
+
+static inline void * __must_check ERR_CAST(__force const void *ptr)
+{
+       /* cast away the const */
+       return (void *) ptr;
+}
+
+static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
+{
+       if (IS_ERR(ptr))
+               return PTR_ERR(ptr);
+       else
+               return 0;
+}
+
+#endif /* _LINUX_ERR_H */