1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 4 Sep 2019 16:55:27 +0200
Subject: [PATCH 295/351] hrtimer: Add a missing bracket and hide
`migration_base' on !SMP
Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=78e97bf152629ea0dc4890964d9a8e92be8c0844
[ Upstream commit 47b6de0b7f22c28b40275aeede3993d807668c3b ]
[ Upstream commit 5d2295f3a93b04986d069ebeaf5b07725f9096c1 ]
The recent change to avoid taking the expiry lock when a timer is currently
migrated missed to add a bracket at the end of the if statement leading to
compile errors. Since that commit the variable `migration_base' is always
used but it is only available on SMP configuration thus leading to another
compile error. The changelog says "The timer base and base->cpu_base
cannot be NULL in the code path", so it is safe to limit this check to SMP
configurations only.
Add the missing bracket to the if statement and hide `migration_base'
behind CONFIG_SMP bars.
[ tglx: Mark the functions inline ... ]
Fixes: 68b2c8c1e4210 ("hrtimer: Don't take expiry_lock when timer is currently migrated")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190904145527.eah7z56ntwobqm6j@linutronix.de
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bigeasy: port back to RT]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/time/hrtimer.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 3f9d156c36f1..0f841f18c363 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -150,6 +150,11 @@ static struct hrtimer_cpu_base migration_cpu_base = {
#define migration_base migration_cpu_base.clock_base[0]
+static inline bool is_migration_base(struct hrtimer_clock_base *base)
+{
+ return base == &migration_base;
+}
+
/*
* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
* means that all timers which are tied to this base via timer->base are
@@ -274,6 +279,11 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
#else /* CONFIG_SMP */
+static inline bool is_migration_base(struct hrtimer_clock_base *base)
+{
+ return false;
+}
+
static inline struct hrtimer_clock_base *
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
@@ -961,7 +971,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer)
{
struct hrtimer_clock_base *base = READ_ONCE(timer->base);
- if (timer->is_soft && base != &migration_base) {
+ if (timer->is_soft && is_migration_base(base)) {
spin_lock(&base->cpu_base->softirq_expiry_lock);
spin_unlock(&base->cpu_base->softirq_expiry_lock);
}
|
