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authorIngo Molnar <mingo@kernel.org>2026-05-29 09:51:00 +0200
committerIngo Molnar <mingo@kernel.org>2026-05-29 09:51:01 +0200
commit83358dec92a4c05c1bbdefa29d677db8a2a2799f (patch)
tree4b59627eaa77b70bd42903886274e5e9afd40a68 /fs
parentee5ce6e9ef0dff9f58c182509212f26dd634b3f7 (diff)
parenta05ca50fc0b832753669ab68fbbb6dc352cf6699 (diff)
downloadlinux-next-history-83358dec92a4c05c1bbdefa29d677db8a2a2799f.tar.gz
Merge branch into tip/master: 'timers/merge'
# New commits in timers/merge: 3eb4923e6851 ("clocksource: Add devm_clocksource_register_*() helpers") c8d32a0389fb ("timers: Fix flseep() typo in kernel-doc comment") 5d330d652d7a ("hrtimer: Fix the bogus return type of __hrtimer_start_range_ns()") 3af1f49f415d ("hrtimer: Return ktime_t from hrtimer_get_next_event()/hrtimer_next_event_without()") 33d4bfc49613 ("clocksource: Clean up clocksource_update_freq() functions") ed3b3c497668 ("alarmtimer: Remove stale return description from alarm_handle_timer()") b00385b8d081 ("selftests/posix_timers: Use CLOCK_THREAD_CPUTIME_ID for ITIMER_PROF measurements") cab0cd0130eb ("scripts/timers: Add timer_migration_tree.py") 5a7dfbcbbdb6 ("timers/migration: Handle capacity in connect tracepoints") 098cbaad8e57 ("timers/migration: Split per-capacity hierarchies") 3ba25488380f ("timers/migration: Track CPUs in a hierarchy") ff65875f80d1 ("timers/migration: Abstract out hierarchy to prepare for CPU capacity awareness") ed78a7019419 ("alarmtimer: Remove unused interfaces") 12e4311aa5b2 ("netfilter: xt_IDLETIMER: Switch to alarm_start_timer()") 9fa2e38ab749 ("power: supply: charger-manager: Switch to alarm_start_timer()") 7dda99952ced ("fs/timerfd: Use the new alarm/hrtimer functions") f4b58f61da79 ("alarmtimer: Convert posix timer functions to alarm_start_timer()") 183d00b72713 ("alarmtimer: Provide alarm_start_timer()") acc071343d29 ("posix-timers: Switch to hrtimer_start_expires_user()") cfb7fe3fdd4c ("posix-timers: Handle the timer_[re]arm() return value") 6fdb2677a594 ("posix-timers: Expand timer_[re]arm() callbacks with a boolean return value") b40c927345a9 ("hrtimer: Use hrtimer_start_expires_user() for hrtimer sleepers") bd5956166d20 ("hrtimer: Provide hrtimer_start_range_ns_user()") 68ed094971b0 ("clocksource/drivers/timer-of: Make the code compatible with modules") 2423405880c2 ("clocksource/drivers/mmio: Make the code compatible with modules") fed9f727cc3f ("clocksource/drivers/sun5i: Handle error returns from devm_reset_control_get_optional_exclusive()") 045a9dac7eb7 ("clocksource/drivers/timer-rtl-otto: Make rttm_cs variable static") b385caf91868 ("dt-bindings: timer: fsl,imxgpt: add compatible string fsl,imx25-epit") Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/timerfd.c117
1 files changed, 68 insertions, 49 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 73104f36bcae0..fe845af0b74e6 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -55,6 +55,15 @@ static inline bool isalarm(struct timerfd_ctx *ctx)
ctx->clockid == CLOCK_BOOTTIME_ALARM;
}
+static void __timerfd_triggered(struct timerfd_ctx *ctx)
+{
+ lockdep_assert_held(&ctx->wqh.lock);
+
+ ctx->expired = 1;
+ ctx->ticks++;
+ wake_up_locked_poll(&ctx->wqh, EPOLLIN);
+}
+
/*
* This gets called when the timer event triggers. We set the "expired"
* flag, but we do not re-arm the timer (in case it's necessary,
@@ -62,13 +71,8 @@ static inline bool isalarm(struct timerfd_ctx *ctx)
*/
static void timerfd_triggered(struct timerfd_ctx *ctx)
{
- unsigned long flags;
-
- spin_lock_irqsave(&ctx->wqh.lock, flags);
- ctx->expired = 1;
- ctx->ticks++;
- wake_up_locked_poll(&ctx->wqh, EPOLLIN);
- spin_unlock_irqrestore(&ctx->wqh.lock, flags);
+ guard(spinlock_irqsave)(&ctx->wqh.lock);
+ __timerfd_triggered(ctx);
}
static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
@@ -184,15 +188,54 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
return remaining < 0 ? 0: remaining;
}
+static void timerfd_alarm_start(struct timerfd_ctx *ctx, ktime_t exp, bool relative)
+{
+ /* Start the timer. If it's expired already, handle the callback. */
+ if (!alarm_start_timer(&ctx->t.alarm, exp, relative))
+ __timerfd_triggered(ctx);
+}
+
+static u64 timerfd_alarm_restart(struct timerfd_ctx *ctx)
+{
+ /* -1 to account for ctx->ticks++ in __timerfd_triggered() */
+ u64 ticks = alarm_forward_now(&ctx->t.alarm, ctx->tintv) - 1;
+
+ timerfd_alarm_start(ctx, alarm_get_expires(&ctx->t.alarm), false);
+ return ticks;
+}
+
+static void timerfd_hrtimer_start(struct timerfd_ctx *ctx, ktime_t exp,
+ const enum hrtimer_mode mode)
+{
+ /* Start the timer. If it's expired already, handle the callback. */
+ if (!hrtimer_start_range_ns_user(&ctx->t.tmr, exp, 0, mode))
+ __timerfd_triggered(ctx);
+}
+
+static u64 timerfd_hrtimer_restart(struct timerfd_ctx *ctx)
+{
+ /* -1 to account for ctx->ticks++ in __timerfd_triggered() */
+ u64 ticks = hrtimer_forward_now(&ctx->t.tmr, ctx->tintv) - 1;
+
+ timerfd_hrtimer_start(ctx, hrtimer_get_expires(&ctx->t.tmr), HRTIMER_MODE_ABS);
+ return ticks;
+}
+
+static u64 timerfd_restart(struct timerfd_ctx *ctx)
+{
+ if (isalarm(ctx))
+ return timerfd_alarm_restart(ctx);
+ return timerfd_hrtimer_restart(ctx);
+}
+
static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
const struct itimerspec64 *ktmr)
{
+ int clockid = ctx->clockid;
enum hrtimer_mode htmode;
ktime_t texp;
- int clockid = ctx->clockid;
- htmode = (flags & TFD_TIMER_ABSTIME) ?
- HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
+ htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
texp = timespec64_to_ktime(ktmr->it_value);
ctx->expired = 0;
@@ -206,20 +249,15 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
timerfd_alarmproc);
} else {
hrtimer_setup(&ctx->t.tmr, timerfd_tmrproc, clockid, htmode);
- hrtimer_set_expires(&ctx->t.tmr, texp);
}
if (texp != 0) {
if (flags & TFD_TIMER_ABSTIME)
texp = timens_ktime_to_host(clockid, texp);
- if (isalarm(ctx)) {
- if (flags & TFD_TIMER_ABSTIME)
- alarm_start(&ctx->t.alarm, texp);
- else
- alarm_start_relative(&ctx->t.alarm, texp);
- } else {
- hrtimer_start(&ctx->t.tmr, texp, htmode);
- }
+ if (isalarm(ctx))
+ timerfd_alarm_start(ctx, texp, !(flags & TFD_TIMER_ABSTIME));
+ else
+ timerfd_hrtimer_start(ctx, texp, htmode);
if (timerfd_canceled(ctx))
return -ECANCELED;
@@ -287,27 +325,19 @@ static ssize_t timerfd_read_iter(struct kiocb *iocb, struct iov_iter *to)
}
if (ctx->ticks) {
- ticks = ctx->ticks;
+ unsigned int expired = ctx->expired;
- if (ctx->expired && ctx->tintv) {
- /*
- * If tintv != 0, this is a periodic timer that
- * needs to be re-armed. We avoid doing it in the timer
- * callback to avoid DoS attacks specifying a very
- * short timer period.
- */
- if (isalarm(ctx)) {
- ticks += alarm_forward_now(
- &ctx->t.alarm, ctx->tintv) - 1;
- alarm_restart(&ctx->t.alarm);
- } else {
- ticks += hrtimer_forward_now(&ctx->t.tmr,
- ctx->tintv) - 1;
- hrtimer_restart(&ctx->t.tmr);
- }
- }
+ ticks = ctx->ticks;
ctx->expired = 0;
ctx->ticks = 0;
+
+ /*
+ * If tintv != 0, this is a periodic timer that needs to be
+ * re-armed. We avoid doing it in the timer callback to avoid
+ * DoS attacks specifying a very short timer period.
+ */
+ if (expired && ctx->tintv)
+ ticks += timerfd_restart(ctx);
}
spin_unlock_irq(&ctx->wqh.lock);
if (ticks) {
@@ -526,18 +556,7 @@ static int do_timerfd_gettime(int ufd, struct itimerspec64 *t)
spin_lock_irq(&ctx->wqh.lock);
if (ctx->expired && ctx->tintv) {
ctx->expired = 0;
-
- if (isalarm(ctx)) {
- ctx->ticks +=
- alarm_forward_now(
- &ctx->t.alarm, ctx->tintv) - 1;
- alarm_restart(&ctx->t.alarm);
- } else {
- ctx->ticks +=
- hrtimer_forward_now(&ctx->t.tmr, ctx->tintv)
- - 1;
- hrtimer_restart(&ctx->t.tmr);
- }
+ ctx->ticks += timerfd_restart(ctx);
}
t->it_value = ktime_to_timespec64(timerfd_get_remaining(ctx));
t->it_interval = ktime_to_timespec64(ctx->tintv);
generated by cgit 1.3-korg (git 2.53.0) at 2026-06-01 04:07:40 +0000