[src/trunk]: src/sys Add a function to compare 2 devhandles.

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9e8a72380193
branches:  trunk
changeset: 359778:9e8a72380193
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Sat Jan 22 11:58:15 2022 +0000

description:
Add a function to compare 2 devhandles.

diffstat:

 sys/kern/subr_device.c |  47 +++++++++++++++++++++++++++++++++++++++++++++--
 sys/sys/device.h       |   3 ++-
 2 files changed, 47 insertions(+), 3 deletions(-)

diffs (85 lines):

diff -r 1302f9988e2e -r 9e8a72380193 sys/kern/subr_device.c
--- a/sys/kern/subr_device.c    Sat Jan 22 11:49:16 2022 +0000
+++ b/sys/kern/subr_device.c    Sat Jan 22 11:58:15 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_device.c,v 1.10 2022/01/21 15:55:36 thorpej Exp $ */
+/*     $NetBSD: subr_device.c,v 1.11 2022/01/22 11:58:15 thorpej Exp $ */
 
 /*
  * Copyright (c) 2006, 2021 The NetBSD Foundation, Inc.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_device.c,v 1.10 2022/01/21 15:55:36 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_device.c,v 1.11 2022/01/22 11:58:15 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -77,6 +77,49 @@
        return handle.impl->type;
 }
 
+int
+devhandle_compare(devhandle_t handle1, devhandle_t handle2)
+{
+       devhandle_type_t type1 = devhandle_type(handle1);
+       devhandle_type_t type2 = devhandle_type(handle2);
+
+       if (type1 == DEVHANDLE_TYPE_INVALID) {
+               return -1;
+       }
+       if (type2 == DEVHANDLE_TYPE_INVALID) {
+               return 1;
+       }
+
+       if (type1 < type2) {
+               return -1;
+       }
+       if (type1 > type2) {
+               return 1;
+       }
+
+       /* For private handles, we also compare the impl pointers. */
+       if (type1 == DEVHANDLE_TYPE_PRIVATE) {
+               intptr_t impl1 = (intptr_t)handle1.impl;
+               intptr_t impl2 = (intptr_t)handle2.impl;
+
+               if (impl1 < impl2) {
+                       return -1;
+               }
+               if (impl1 > impl2) {
+                       return 1;
+               }
+       }
+
+       if (handle1.integer < handle2.integer) {
+               return -1;
+       }
+       if (handle1.integer > handle2.integer) {
+               return 1;
+       }
+
+       return 0;
+}
+
 device_call_t
 devhandle_lookup_device_call(devhandle_t handle, const char *name,
     devhandle_t *call_handlep)
diff -r 1302f9988e2e -r 9e8a72380193 sys/sys/device.h
--- a/sys/sys/device.h  Sat Jan 22 11:49:16 2022 +0000
+++ b/sys/sys/device.h  Sat Jan 22 11:58:15 2022 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: device.h,v 1.177 2022/01/22 11:16:00 thorpej Exp $ */
+/* $NetBSD: device.h,v 1.178 2022/01/22 11:58:15 thorpej Exp $ */
 
 /*
  * Copyright (c) 2021 The NetBSD Foundation, Inc.
@@ -674,6 +674,7 @@
 bool           devhandle_is_valid(devhandle_t);
 devhandle_t    devhandle_invalid(void);
 devhandle_type_t devhandle_type(devhandle_t);
+int            devhandle_compare(devhandle_t, devhandle_t);
 
 device_call_t  devhandle_lookup_device_call(devhandle_t, const char *,
                    devhandle_t *);