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Diffstat (limited to 'fs/timerfd.c')
-rw-r--r--fs/timerfd.c57
1 files changed, 51 insertions, 6 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c
index 8c4fc1425b3e..7e14c9e7c4ee 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -26,10 +26,12 @@
struct timerfd_ctx {
struct hrtimer tmr;
ktime_t tintv;
+ ktime_t moffs;
wait_queue_head_t wqh;
u64 ticks;
int expired;
int clockid;
+ bool might_cancel;
};
/*
@@ -59,24 +61,52 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
}
-static void timerfd_setup(struct timerfd_ctx *ctx, int flags,
- const struct itimerspec *ktmr)
+static bool timerfd_canceled(struct timerfd_ctx *ctx)
+{
+ ktime_t moffs;
+
+ if (!ctx->might_cancel)
+ return false;
+
+ moffs = ktime_get_monotonic_offset();
+
+ if (moffs.tv64 == ctx->moffs.tv64)
+ return false;
+
+ ctx->moffs = moffs;
+ return true;
+}
+
+static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
+ const struct itimerspec *ktmr)
{
enum hrtimer_mode htmode;
ktime_t texp;
+ int clockid = ctx->clockid;
htmode = (flags & TFD_TIMER_ABSTIME) ?
HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
+ ctx->might_cancel = false;
+ if (htmode == HRTIMER_MODE_ABS && ctx->clockid == CLOCK_REALTIME &&
+ (flags & TFD_TIMER_CANCELON_SET)) {
+ clockid = CLOCK_REALTIME_COS;
+ ctx->might_cancel = true;
+ }
+
texp = timespec_to_ktime(ktmr->it_value);
ctx->expired = 0;
ctx->ticks = 0;
ctx->tintv = timespec_to_ktime(ktmr->it_interval);
- hrtimer_init(&ctx->tmr, ctx->clockid, htmode);
+ hrtimer_init(&ctx->tmr, clockid, htmode);
hrtimer_set_expires(&ctx->tmr, texp);
ctx->tmr.function = timerfd_tmrproc;
- if (texp.tv64 != 0)
+ if (texp.tv64 != 0) {
hrtimer_start(&ctx->tmr, texp, htmode);
+ if (timerfd_canceled(ctx))
+ return -ECANCELED;
+ }
+ return 0;
}
static int timerfd_release(struct inode *inode, struct file *file)
@@ -118,8 +148,21 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
res = -EAGAIN;
else
res = wait_event_interruptible_locked_irq(ctx->wqh, ctx->ticks);
+
if (ctx->ticks) {
ticks = ctx->ticks;
+
+ /*
+ * If clock has changed, we do not care about the
+ * ticks and we do not rearm the timer. Userspace must
+ * reevaluate anyway.
+ */
+ if (timerfd_canceled(ctx)) {
+ ticks = 0;
+ ctx->expired = 0;
+ res = -ECANCELED;
+ }
+
if (ctx->expired && ctx->tintv.tv64) {
/*
* If tintv.tv64 != 0, this is a periodic timer that
@@ -183,6 +226,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
init_waitqueue_head(&ctx->wqh);
ctx->clockid = clockid;
hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);
+ ctx->moffs = ktime_get_monotonic_offset();
ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
@@ -199,6 +243,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
struct file *file;
struct timerfd_ctx *ctx;
struct itimerspec ktmr, kotmr;
+ int ret;
if (copy_from_user(&ktmr, utmr, sizeof(ktmr)))
return -EFAULT;
@@ -240,14 +285,14 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
/*
* Re-program the timer to the new value ...
*/
- timerfd_setup(ctx, flags, &ktmr);
+ ret = timerfd_setup(ctx, flags, &ktmr);
spin_unlock_irq(&ctx->wqh.lock);
fput(file);
if (otmr && copy_to_user(otmr, &kotmr, sizeof(kotmr)))
return -EFAULT;
- return 0;
+ return ret;
}
SYSCALL_DEFINE2(timerfd_gettime, int, ufd, struct itimerspec __user *, otmr)