Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761298AbaGRJxA (ORCPT ); Fri, 18 Jul 2014 05:53:00 -0400 Received: from terminus.zytor.com ([198.137.202.10]:36341 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761232AbaGRJw5 (ORCPT ); Fri, 18 Jul 2014 05:52:57 -0400 Date: Fri, 18 Jul 2014 02:52:34 -0700 From: tip-bot for Cyrill Gorcunov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, gorcunov@openvz.org, xemul@parallels.com, avagin@openvz.org, cov@codeaurora.org, arnd@arndb.de, akpm@linux-foundation.org, tglx@linutronix.de, vdavydov@parallels.com, mtk.manpages@gmail.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, gorcunov@openvz.org, xemul@parallels.com, avagin@openvz.org, cov@codeaurora.org, arnd@arndb.de, akpm@linux-foundation.org, tglx@linutronix.de, vdavydov@parallels.com, mtk.manpages@gmail.com In-Reply-To: <20140715215703.285617923@openvz.org> References: <20140715215703.285617923@openvz.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/core] timerfd: Implement timerfd_ioctl method to restore timerfd_ctx::ticks, v3 Git-Commit-ID: 5442e9fbd7c23172a1c9bc736629cd123a9923f0 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 5442e9fbd7c23172a1c9bc736629cd123a9923f0 Gitweb: http://git.kernel.org/tip/5442e9fbd7c23172a1c9bc736629cd123a9923f0 Author: Cyrill Gorcunov AuthorDate: Wed, 16 Jul 2014 01:54:54 +0400 Committer: Thomas Gleixner CommitDate: Fri, 18 Jul 2014 11:49:57 +0200 timerfd: Implement timerfd_ioctl method to restore timerfd_ctx::ticks, v3 The read() of timerfd files allows to fetch the number of timer ticks while there is no way to set it back from userspace. To restore the timer's state as it was at checkpoint moment we need a path to bring @ticks back. Initially I thought about writing ticks back via write() interface but it seems such API is somehow obscure. Instead implement timerfd_ioctl() method with TFD_IOC_SET_TICKS command which allows to adjust @ticks into non-zero value waking up the waiters. I wrapped code with CONFIG_CHECKPOINT_RESTORE which can be dropped off if there users except c/r camp appear. v2 (by akpm@): - Use define timerfd_ioctl NULL for non c/r config v3: - Use copy_from_user for @ticks fetching since not all arch support get_user for 8 byte argument Signed-off-by: Cyrill Gorcunov Cc: Andrew Morton Cc: Michael Kerrisk Cc: Andrey Vagin Cc: Arnd Bergmann Cc: Christopher Covington Cc: Pavel Emelyanov Cc: Vladimir Davydov Link: http://lkml.kernel.org/r/20140715215703.285617923@openvz.org Signed-off-by: Thomas Gleixner --- fs/timerfd.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/timerfd.h | 5 +++++ 2 files changed, 42 insertions(+) diff --git a/fs/timerfd.c b/fs/timerfd.c index 77183f0..709603c 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -315,12 +315,49 @@ static int timerfd_show(struct seq_file *m, struct file *file) #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; + if (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) diff --git a/include/linux/timerfd.h b/include/linux/timerfd.h index d3b57fa..bd36ce4 100644 --- a/include/linux/timerfd.h +++ b/include/linux/timerfd.h @@ -11,6 +11,9 @@ /* For O_CLOEXEC and O_NONBLOCK */ #include +/* For _IO helpers */ +#include + /* * CAREFUL: Check include/asm-generic/fcntl.h when defining * new flags, since they might collide with O_* ones. We want @@ -29,4 +32,6 @@ /* Flags for timerfd_settime. */ #define TFD_SETTIME_FLAGS (TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET) +#define TFD_IOC_SET_TICKS _IOW('T', 0, u64) + #endif /* _LINUX_TIMERFD_H */ -- 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/