lkml.org 
[lkml]   [2007]   [Mar]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [patch 6/13] signalfd/timerfd/asyncfd v5 - timerfd core ...
From
Date
Davide,

On Wed, 2007-03-14 at 15:19 -0700, Davide Libenzi wrote:

> +static int timerfd_tmrproc(struct hrtimer *htmr)
> +{
> + struct timerfd_ctx *ctx = container_of(htmr, struct timerfd_ctx, tmr);
> + int rval = HRTIMER_NORESTART;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ctx->lock, flags);
> + ctx->ticks++;
> + wake_up_locked(&ctx->wqh);
> + if (ctx->tintv.tv64 != 0) {
> + hrtimer_forward(htmr, htmr->base->softirq_time, ctx->tintv);

Sorry, I missed that in the first reviews. Please use
hrtimer_cb_get_time(htmr) instead of htmr->base->softirq_time, so this
is high res timer safe.

> + rval = HRTIMER_RESTART;
> + }
> + spin_unlock_irqrestore(&ctx->lock, flags);
> +
> + return rval;
> +}
> +
> +
> +static int timerfd_setup(struct timerfd_ctx *ctx, int clockid, int flags,
> + const struct itimerspec *ktmr)
> +{

Make this void, returns 0 anyway

> + enum hrtimer_mode htmode;
> +
> + htmode = (flags & TFD_TIMER_ABSTIME) ? HRTIMER_ABS: HRTIMER_REL;
> +
> + ctx->ticks = 0;
> + ctx->clockid = clockid;
> + ctx->flags = flags;
> + ctx->texp = timespec_to_ktime(ktmr->it_value);

clockid is stored in the timer on setup, so no need to store it again.
expiry time and flags are not used after setup.

Please remove those fields.

> + ctx->tintv = timespec_to_ktime(ktmr->it_interval);
> + hrtimer_init(&ctx->tmr, ctx->clockid, htmode);
> + ctx->tmr.expires = ctx->texp;
> + ctx->tmr.function = timerfd_tmrproc;
> + if (ctx->texp.tv64 != 0)
> + hrtimer_start(&ctx->tmr, ctx->texp, htmode);
> +
> + return 0;
> +}
> +
> + if (ufd == -1) {
> + ctx = kmem_cache_alloc(timerfd_ctx_cachep, GFP_KERNEL);
> + if (!ctx)
> + return -ENOMEM;
> +
> + init_waitqueue_head(&ctx->wqh);
> + spin_lock_init(&ctx->lock);
> + ctx->clockid = -1;
> +
> + error = timerfd_setup(ctx, clockid, flags, &ktmr);
> + if (error)
> + goto err_ctxfree;

Timer setup can not fail

> + /*
> + * When we call this, the initialization must be complete, since
> + * aino_getfd() will install the fd.
> + */
> + error = aino_getfd(&ufd, &inode, &file, "[timerfd]",
> + &timerfd_fops, ctx);
> + if (error)
> + goto err_ctxfree;

Again: Please turn this around. No need to start the timer before we
know, that everything works.

> + } else {
> + file = fget(ufd);
> + if (!file)
> + return -EBADF;
> + ctx = file->private_data;
> + if (file->f_op != &timerfd_fops) {
> + fput(file);
> + return -EINVAL;
> + }
> + /*
> + * We need to stop the existing timer before reprogramming
> + * it to the new values.
> + */
> + for (;;) {
> + spin_lock_irq(&ctx->lock);
> + if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
> + break;
> + spin_unlock_irq(&ctx->lock);
> + cpu_relax();
> + }
> + /*
> + * Re-program the timer to the new value ...
> + */
> + error = timerfd_setup(ctx, clockid, flags, &ktmr);

Timer setup can not fail

> + spin_unlock_irq(&ctx->lock);
> + fput(file);
> + if (error)
> + return error;
> + }
> +
> + return ufd;
> +
> +err_ctxfree:
> + timerfd_cleanup(ctx);
> + return error;
> +}
> +
> +
> +static void timerfd_cleanup(struct timerfd_ctx *ctx)
> +{
> + if (ctx->clockid >= 0)
> + hrtimer_cancel(&ctx->tmr);

You don't have a file descriptor, when the setup failed. So the timer is
always initialized.

> + kmem_cache_free(timerfd_ctx_cachep, ctx);
> +}
> +
> +
> +static int timerfd_close(struct inode *inode, struct file *file)
> +{
> + timerfd_cleanup(file->private_data);
> + return 0;
> +}
> +

Please move the timerfd_cleanup code into close().

tglx


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-15 22:55    [W:0.278 / U:0.416 seconds]
©2003-2011 Jasper Spaans. Advertise on this site