Merge tag 'timers-v6.11-rc1' of https://git.linaro.org/people/daniel.lezcano/linux into timers/core

Pull clocksource/event driver updates from Daniel Lezcano:

  - Remove unnecessary local variables initialization as they will be
    initialized in the code path anyway right after on the ARM arch
    timer and the ARM global timer (Li kunyu)

  - Fix a race condition in the interrupt leading to a deadlock on the
    SH CMT driver. Note that this fix was not tested on the platform
    using this timer but the fix seems reasonable enough to be picked
    confidently (Niklas Söderlund)

  - Increase the rating of the gic-timer and use the configured width
    clocksource register on the MIPS architecture (Jiaxun Yang)

  - Add the DT bindings for the TMU on the Renesas platforms (Geert
    Uytterhoeven)

  - Add the DT bindings for the SOPHGO SG2002 clint on RiscV (Thomas
    Bonnefille)

  - Add the rtl-otto timer driver along with the DT bindings for the
    Realtek platform (Chris Packham)

Link: https://lore.kernel.org/all/91cd05de-4c5d-4242-a381-3b8a4fe6a2a2@linaro.org

1 files changed, 50 insertions, 4 deletions

diff --git a/lib/closure.c b/lib/closure.c
index 07409e9e35a5..c971216d9d77 100644
--- a/lib/closure.c
+++ b/lib/closure.c
@@ -13,14 +13,25 @@
 #include <linux/seq_file.h>
 #include <linux/sched/debug.h>
 
-static inline void closure_put_after_sub(struct closure *cl, int flags)
+static inline void closure_put_after_sub_checks(int flags)
 {
 	int r = flags & CLOSURE_REMAINING_MASK;
 
-	BUG_ON(flags & CLOSURE_GUARD_MASK);
-	BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
+	if (WARN(flags & CLOSURE_GUARD_MASK,
+		 "closure has guard bits set: %x (%u)",
+		 flags & CLOSURE_GUARD_MASK, (unsigned) __fls(r)))
+		r &= ~CLOSURE_GUARD_MASK;
+
+	WARN(!r && (flags & ~CLOSURE_DESTRUCTOR),
+	     "closure ref hit 0 with incorrect flags set: %x (%u)",
+	     flags & ~CLOSURE_DESTRUCTOR, (unsigned) __fls(flags));
+}
+
+static inline void closure_put_after_sub(struct closure *cl, int flags)
+{
+	closure_put_after_sub_checks(flags);
 
-	if (!r) {
+	if (!(flags & CLOSURE_REMAINING_MASK)) {
 		smp_acquire__after_ctrl_dep();
 
 		cl->closure_get_happened = false;
@@ -139,6 +150,41 @@ void __sched __closure_sync(struct closure *cl)
 }
 EXPORT_SYMBOL(__closure_sync);
 
+/*
+ * closure_return_sync - finish running a closure, synchronously (i.e. waiting
+ * for outstanding get()s to finish) and returning once closure refcount is 0.
+ *
+ * Unlike closure_sync() this doesn't reinit the ref to 1; subsequent
+ * closure_get_not_zero() calls waill fail.
+ */
+void __sched closure_return_sync(struct closure *cl)
+{
+	struct closure_syncer s = { .task = current };
+
+	cl->s = &s;
+	set_closure_fn(cl, closure_sync_fn, NULL);
+
+	unsigned flags = atomic_sub_return_release(1 + CLOSURE_RUNNING - CLOSURE_DESTRUCTOR,
+						   &cl->remaining);
+
+	closure_put_after_sub_checks(flags);
+
+	if (unlikely(flags & CLOSURE_REMAINING_MASK)) {
+		while (1) {
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			if (s.done)
+				break;
+			schedule();
+		}
+
+		__set_current_state(TASK_RUNNING);
+	}
+
+	if (cl->parent)
+		closure_put(cl->parent);
+}
+EXPORT_SYMBOL(closure_return_sync);
+
 int __sched __closure_sync_timeout(struct closure *cl, unsigned long timeout)
 {
 	struct closure_syncer s = { .task = current };