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authorDave Airlie <airlied@redhat.com>2014-01-20 10:21:54 +1000
committerDave Airlie <airlied@redhat.com>2014-01-20 10:21:54 +1000
commitcfd72a4c2089aa3938f37281a34d6eb3306d5fd8 (patch)
treee63f6df423aeb59d1ea5f7af3597d6718e75c335 /drivers/tty/tty_ldsem.c
parent9354eafd893f45320a37da360e1728104e49cc2f (diff)
parent0d9d349d8788d30f3fc3bb39279c370f94d9dbec (diff)
Merge branch 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel into drm-next
drm-intel-next-2014-01-10: - final bits for runtime D3 on Haswell from Paul (now enabled fully) - parse the backlight modulation freq information in the VBT from Jani (but not yet used) - more watermark improvements from Ville for ilk-ivb and bdw - bugfixes for fastboot from Jesse - watermark fix for i830M (but not yet everything) - vlv vga hotplug w/a (Imre) - piles of other small improvements, cleanups and fixes all over Note that the pull request includes a backmerge of the last drm-fixes pulled into Linus' tree - things where getting a bit too messy. So the shortlog also contains a bunch of patches from Linus tree. Please yell if you want me to frob it for you a bit. * 'drm-intel-next' of git://people.freedesktop.org/~danvet/drm-intel: (609 commits) drm/i915/bdw: make sure south port interrupts are enabled properly v2 drm/i915: Include more information in disabled hotplug interrupt warning drm/i915: Only complain about a rogue hotplug IRQ after disabling drm/i915: Only WARN about a stuck hotplug irq ONCE drm/i915: s/hotplugt_status_gen4/hotplug_status_g4x/
Diffstat (limited to 'drivers/tty/tty_ldsem.c')
-rw-r--r--drivers/tty/tty_ldsem.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/tty/tty_ldsem.c b/drivers/tty/tty_ldsem.c
index 22fad8ad5ac2..d8a55e87877f 100644
--- a/drivers/tty/tty_ldsem.c
+++ b/drivers/tty/tty_ldsem.c
@@ -86,11 +86,21 @@ static inline long ldsem_atomic_update(long delta, struct ld_semaphore *sem)
return atomic_long_add_return(delta, (atomic_long_t *)&sem->count);
}
+/*
+ * ldsem_cmpxchg() updates @*old with the last-known sem->count value.
+ * Returns 1 if count was successfully changed; @*old will have @new value.
+ * Returns 0 if count was not changed; @*old will have most recent sem->count
+ */
static inline int ldsem_cmpxchg(long *old, long new, struct ld_semaphore *sem)
{
- long tmp = *old;
- *old = atomic_long_cmpxchg(&sem->count, *old, new);
- return *old == tmp;
+ long tmp = atomic_long_cmpxchg(&sem->count, *old, new);
+ if (tmp == *old) {
+ *old = new;
+ return 1;
+ } else {
+ *old = tmp;
+ return 0;
+ }
}
/*