[src/riastradh-drm2]: src/sys/external/bsd/drm2/dist/drm Replace trivial spin...

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

details:   https://anonhg.NetBSD.org/src/rev/6eebd4c589b9
branches:  riastradh-drm2
changeset: 788050:6eebd4c589b9
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Jul 24 02:00:22 2013 +0000

description:
Replace trivial spinlock by atomics in drm_getmagic.

(This whole drm_getmagic thing smells awfully fishy...)

diffstat:

 sys/external/bsd/drm2/dist/drm/drm_auth.c |  6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diffs (29 lines):

diff -r d61cad16f63c -r 6eebd4c589b9 sys/external/bsd/drm2/dist/drm/drm_auth.c
--- a/sys/external/bsd/drm2/dist/drm/drm_auth.c Wed Jul 24 02:00:07 2013 +0000
+++ b/sys/external/bsd/drm2/dist/drm/drm_auth.c Wed Jul 24 02:00:22 2013 +0000
@@ -142,7 +142,9 @@
 int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
 {
        static drm_magic_t sequence = 0;
+#ifndef __NetBSD__
        static DEFINE_SPINLOCK(lock);
+#endif
        struct drm_auth *auth = data;
 
        /* Find unique magic */
@@ -150,11 +152,15 @@
                auth->magic = file_priv->magic;
        } else {
                do {
+#ifdef __NetBSD__
+                       auth->magic = atomic_inc_uint_nv(&sequence);
+#else
                        spin_lock(&lock);
                        if (!sequence)
                                ++sequence;     /* reserve 0 */
                        auth->magic = sequence++;
                        spin_unlock(&lock);
+#endif
                } while (drm_find_file(file_priv->master, auth->magic));
                file_priv->magic = auth->magic;
                drm_add_magic(file_priv->master, file_priv, auth->magic);