afs: remove unnecessary dentry_unhash on rmdir, dir rename

[pandora-kernel.git] / fs / timerfd.c

diff --git a/fs/timerfd.c b/fs/timerfd.c
index 8c4fc14..f67acbd 100644 (file)
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -22,16 +22,24 @@
 #include <linux/anon_inodes.h>
 #include <linux/timerfd.h>
 #include <linux/syscalls.h>
+#include <linux/rcupdate.h>
 
 struct timerfd_ctx {
        struct hrtimer tmr;
        ktime_t tintv;
+       ktime_t moffs;
        wait_queue_head_t wqh;
        u64 ticks;
        int expired;
        int clockid;
+       struct rcu_head rcu;
+       struct list_head clist;
+       bool might_cancel;
 };
 
+static LIST_HEAD(cancel_list);
+static DEFINE_SPINLOCK(cancel_lock);
+
 /*
  * 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,
@@ -51,6 +59,63 @@ static enum hrtimer_restart timerfd_tmrproc(struct hrtimer *htmr)
        return HRTIMER_NORESTART;
 }
 
+/*
+ * Called when the clock was set to cancel the timers in the cancel
+ * list.
+ */
+void timerfd_clock_was_set(void)
+{
+       ktime_t moffs = ktime_get_monotonic_offset();
+       struct timerfd_ctx *ctx;
+       unsigned long flags;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(ctx, &cancel_list, clist) {
+               if (!ctx->might_cancel)
+                       continue;
+               spin_lock_irqsave(&ctx->wqh.lock, flags);
+               if (ctx->moffs.tv64 != moffs.tv64) {
+                       ctx->moffs.tv64 = KTIME_MAX;
+                       wake_up_locked(&ctx->wqh);
+               }
+               spin_unlock_irqrestore(&ctx->wqh.lock, flags);
+       }
+       rcu_read_unlock();
+}
+
+static void timerfd_remove_cancel(struct timerfd_ctx *ctx)
+{
+       if (ctx->might_cancel) {
+               ctx->might_cancel = false;
+               spin_lock(&cancel_lock);
+               list_del_rcu(&ctx->clist);
+               spin_unlock(&cancel_lock);
+       }
+}
+
+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();
+       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->might_cancel) {
+                       ctx->might_cancel = true;
+                       spin_lock(&cancel_lock);
+                       list_add_rcu(&ctx->clist, &cancel_list);
+                       spin_unlock(&cancel_lock);
+               }
+       } else if (ctx->might_cancel) {
+               timerfd_remove_cancel(ctx);
+       }
+}
+
 static ktime_t timerfd_get_remaining(struct timerfd_ctx *ctx)
 {
        ktime_t remaining;
@@ -59,11 +124,12 @@ 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 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;
@@ -72,19 +138,24 @@ static void 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, 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)
 {
        struct timerfd_ctx *ctx = file->private_data;
 
+       timerfd_remove_cancel(ctx);
        hrtimer_cancel(&ctx->tmr);
-       kfree(ctx);
+       kfree_rcu(ctx, rcu);
        return 0;
 }
 
@@ -118,8 +189,21 @@ 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 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)) {
+               ctx->ticks = 0;
+               ctx->expired = 0;
+               res = -ECANCELED;
+       }
+
        if (ctx->ticks) {
                ticks = ctx->ticks;
+
                if (ctx->expired && ctx->tintv.tv64) {
                        /*
                         * If tintv.tv64 != 0, this is a periodic timer that
@@ -183,6 +267,7 @@ 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 +284,7 @@ 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;
@@ -213,6 +299,8 @@ SYSCALL_DEFINE4(timerfd_settime, int, ufd, int, flags,
                return PTR_ERR(file);
        ctx = file->private_data;
 
+       timerfd_setup_cancel(ctx, flags);
+
        /*
         * We need to stop the existing timer before reprogramming
         * it to the new values.
@@ -240,14 +328,14 @@ 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)