usb: dwc3: rockchip: fix possible circular deadlock
[firefly-linux-kernel-4.4.55.git] / fs / timerfd.c
index 32b644f0369020a1c11e1fc7378bae581e4185c7..053818dd6c18be8f228e1c40483e50d78aa78007 100644 (file)
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/alarmtimer.h>
 #include <linux/file.h>
 #include <linux/poll.h>
 #include <linux/init.h>
 #include <linux/rcupdate.h>
 
 struct timerfd_ctx {
-       struct hrtimer tmr;
+       union {
+               struct hrtimer tmr;
+               struct alarm alarm;
+       } t;
        ktime_t tintv;
        ktime_t moffs;
        wait_queue_head_t wqh;
        u64 ticks;
-       int expired;
        int clockid;
+       short unsigned expired;
+       short unsigned settime_flags;   /* to show in fdinfo */
        struct rcu_head rcu;
        struct list_head clist;
        bool might_cancel;
@@ -41,14 +46,19 @@ struct timerfd_ctx {
 static LIST_HEAD(cancel_list);
 static DEFINE_SPINLOCK(cancel_lock);
 
+static inline bool isalarm(struct timerfd_ctx *ctx)
+{
+       return ctx->clockid == CLOCK_REALTIME_ALARM ||
+               ctx->clockid == CLOCK_BOOTTIME_ALARM;
+}
+
 /*
  * 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,
  * tintv.tv64 != 0) until the timer is accessed.
  */
-static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
+static void timerfd_triggered(struct timerfd_ctx *ctx)
 {
-       struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
        unsigned long flags;
 
        spin_lock_irqsave(&ctx->wqh.lock, flags);
@@ -56,10 +66,25 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
        ctx->ticks++;
        wake_up_locked(&ctx->wqh);
        spin_unlock_irqrestore(&ctx->wqh.lock, flags);
+}
 
+static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
+{
+       struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx,
+                                              t.tmr);
+       timerfd_triggered(ctx);
        return HRTIMER_NORESTART;
 }
 
+static enum alarmtimer_restart timerfd_alarmproc(struct alarm *alarm,
+       ktime_t now)
+{
+       struct timerfd_ctx *ctx = container_of(alarm, struct timerfd_ctx,
+                                              t.alarm);
+       timerfd_triggered(ctx);
+       return ALARMTIMER_NORESTART;
+}
+
 /*
  * Called when the clock was set to cancel the timers in the cancel
  * list. This will wake up processes waiting on these timers. The
@@ -68,7 +93,7 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
  */
 void timerfd_clock_was_set(void)
 {
-       ktime_t moffs = ktime_get_monotonic_offset();
+       ktime_t moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
        struct timerfd_ctx *ctx;
        unsigned long flags;
 
@@ -101,14 +126,15 @@ static bool timerfd_canceled(struct timerfd_ctx *ctx)
 {
        if (!ctx->might_cancel || ctx->moffs.tv64 != KTIME_MAX)
                return false;
-       ctx->moffs = ktime_get_monotonic_offset();
+       ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
        return true;
 }
 
 static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags)
 {
-       if (ctx->clockid == CLOCK_REALTIME && (flags & TFD_TIMER_ABSTIME) &&
-           (flags & TFD_TIMER_CANCEL_ON_SET)) {
+       if ((ctx->clockid == CLOCK_REALTIME ||
+            ctx->clockid == CLOCK_REALTIME_ALARM) &&
+           (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) {
                if (!ctx->might_cancel) {
                        ctx->might_cancel = true;
                        spin_lock(&cancel_lock);
@@ -124,7 +150,11 @@ static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
 {
        ktime_t remaining;
 
-       remaining = hrtimer_expires_remaining(&ctx->tmr);
+       if (isalarm(ctx))
+               remaining = alarm_expires_remaining(&ctx->t.alarm);
+       else
+               remaining = hrtimer_expires_remaining_adjusted(&ctx->t.tmr);
+
        return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
 }
 
@@ -142,14 +172,33 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
        ctx->expired = 0;
        ctx->ticks = 0;
        ctx->tintv = timespec_to_ktime(ktmr->it_interval);
-       hrtimer_init(&ctx->tmr, clockid, htmode);
-       hrtimer_set_expires(&ctx->tmr, texp);
-       ctx->tmr.function = timerfd_tmrproc;
+
+       if (isalarm(ctx)) {
+               alarm_init(&ctx->t.alarm,
+                          ctx->clockid == CLOCK_REALTIME_ALARM ?
+                          ALARM_REALTIME : ALARM_BOOTTIME,
+                          timerfd_alarmproc);
+       } else {
+               hrtimer_init(&ctx->t.tmr, clockid, htmode);
+               hrtimer_set_expires(&ctx->t.tmr, texp);
+               ctx->t.tmr.function = timerfd_tmrproc;
+       }
+
        if (texp.tv64 != 0) {
-               hrtimer_start(&ctx->tmr, texp, htmode);
+               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 (timerfd_canceled(ctx))
                        return -ECANCELED;
        }
+
+       ctx->settime_flags = flags & TFD_SETTIME_FLAGS;
        return 0;
 }
 
@@ -158,7 +207,11 @@ static int timerfd_release(struct inode *inode, struct file *file)
        struct timerfd_ctx *ctx = file->private_data;
 
        timerfd_remove_cancel(ctx);
-       hrtimer_cancel(&ctx->tmr);
+
+       if (isalarm(ctx))
+               alarm_cancel(&ctx->t.alarm);
+       else
+               hrtimer_cancel(&ctx->t.tmr);
        kfree_rcu(ctx, rcu);
        return 0;
 }
@@ -215,9 +268,15 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
                         * callback to avoid DoS attacks specifying a very
                         * short timer period.
                         */
-                       ticks += hrtimer_forward_now(&ctx->tmr,
-                                                    ctx->tintv) - 1;
-                       hrtimer_restart(&ctx->tmr);
+                       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);
+                       }
                }
                ctx->expired = 0;
                ctx->ticks = 0;
@@ -228,11 +287,77 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
        return res;
 }
 
+#ifdef CONFIG_PROC_FS
+static void timerfd_show(struct seq_file *m, struct file *file)
+{
+       struct timerfd_ctx *ctx = file->private_data;
+       struct itimerspec t;
+
+       spin_lock_irq(&ctx->wqh.lock);
+       t.it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
+       t.it_interval = ktime_to_timespec(ctx->tintv);
+       spin_unlock_irq(&ctx->wqh.lock);
+
+       seq_printf(m,
+                  "clockid: %d\n"
+                  "ticks: %llu\n"
+                  "settime flags: 0%o\n"
+                  "it_value: (%llu, %llu)\n"
+                  "it_interval: (%llu, %llu)\n",
+                  ctx->clockid,
+                  (unsigned long long)ctx->ticks,
+                  ctx->settime_flags,
+                  (unsigned long long)t.it_value.tv_sec,
+                  (unsigned long long)t.it_value.tv_nsec,
+                  (unsigned long long)t.it_interval.tv_sec,
+                  (unsigned long long)t.it_interval.tv_nsec);
+}
+#else
+#define timerfd_show NULL
+#endif
+
+#ifdef CONFIG_CHECKPOINT_RESTORE
+static long timerfd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       struct timerfd_ctx *ctx = file->private_data;
+       int ret = 0;
+
+       switch (cmd) {
+       case TFD_IOC_SET_TICKS: {
+               u64 ticks;
+
+               if (copy_from_user(&ticks, (u64 __user *)arg, sizeof(ticks)))
+                       return -EFAULT;
+               if (!ticks)
+                       return -EINVAL;
+
+               spin_lock_irq(&ctx->wqh.lock);
+               if (!timerfd_canceled(ctx)) {
+                       ctx->ticks = ticks;
+                       wake_up_locked(&ctx->wqh);
+               } else
+                       ret = -ECANCELED;
+               spin_unlock_irq(&ctx->wqh.lock);
+               break;
+       }
+       default:
+               ret = -ENOTTY;
+               break;
+       }
+
+       return ret;
+}
+#else
+#define timerfd_ioctl NULL
+#endif
+
 static const struct file_operations timerfd_fops = {
        .release        = timerfd_release,
        .poll           = timerfd_poll,
        .read           = timerfd_read,
        .llseek         = noop_llseek,
+       .show_fdinfo    = timerfd_show,
+       .unlocked_ioctl = timerfd_ioctl,
 };
 
 static int timerfd_fget(int fd, struct fd *p)
@@ -259,7 +384,10 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 
        if ((flags & ~TFD_CREATE_FLAGS) ||
            (clockid != CLOCK_MONOTONIC &&
-            clockid != CLOCK_REALTIME))
+            clockid != CLOCK_REALTIME &&
+            clockid != CLOCK_REALTIME_ALARM &&
+            clockid != CLOCK_BOOTTIME &&
+            clockid != CLOCK_BOOTTIME_ALARM))
                return -EINVAL;
 
        ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
@@ -268,8 +396,16 @@ 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();
+
+       if (isalarm(ctx))
+               alarm_init(&ctx->t.alarm,
+                          ctx->clockid == CLOCK_REALTIME_ALARM ?
+                          ALARM_REALTIME : ALARM_BOOTTIME,
+                          timerfd_alarmproc);
+       else
+               hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
+
+       ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
 
        ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
                               O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
@@ -305,8 +441,14 @@ static int do_timerfd_settime(int ufd, int flags,
         */
        for (;;) {
                spin_lock_irq(&ctx->wqh.lock);
-               if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
-                       break;
+
+               if (isalarm(ctx)) {
+                       if (alarm_try_to_cancel(&ctx->t.alarm) >= 0)
+                               break;
+               } else {
+                       if (hrtimer_try_to_cancel(&ctx->t.tmr) >= 0)
+                               break;
+               }
                spin_unlock_irq(&ctx->wqh.lock);
                cpu_relax();
        }
@@ -317,8 +459,12 @@ static int do_timerfd_settime(int ufd, int flags,
         * We do not update "ticks" and "expired" since the timer will be
         * re-programmed again in the following timerfd_setup() call.
         */
-       if (ctx->expired && ctx->tintv.tv64)
-               hrtimer_forward_now(&ctx->tmr, ctx->tintv);
+       if (ctx->expired && ctx->tintv.tv64) {
+               if (isalarm(ctx))
+                       alarm_forward_now(&ctx->t.alarm, ctx->tintv);
+               else
+                       hrtimer_forward_now(&ctx->t.tmr, ctx->tintv);
+       }
 
        old->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
        old->it_interval = ktime_to_timespec(ctx->tintv);
@@ -345,9 +491,18 @@ static int do_timerfd_gettime(int ufd, struct itimerspec *t)
        spin_lock_irq(&ctx->wqh.lock);
        if (ctx->expired && ctx->tintv.tv64) {
                ctx->expired = 0;
-               ctx->ticks +=
-                       hrtimer_forward_now(&ctx->tmr, ctx->tintv) - 1;
-               hrtimer_restart(&ctx->tmr);
+
+               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);
+               }
        }
        t->it_value = ktime_to_timespec(timerfd_get_remaining(ctx));
        t->it_interval = ktime_to_timespec(ctx->tintv);