From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423036AbbEONtM (ORCPT ); Fri, 15 May 2015 09:49:12 -0400 Received: from mail-ob0-f172.google.com ([209.85.214.172]:34192 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422753AbbEONtI (ORCPT ); Fri, 15 May 2015 09:49:08 -0400 MIME-Version: 1.0 In-Reply-To: <5555F5C5.8050806@roeck-us.net> References: <=fu.wei@linaro.org> <1431689090-3125-1-git-send-email-fu.wei@linaro.org> <5555F5C5.8050806@roeck-us.net> Date: Fri, 15 May 2015 21:49:07 +0800 Message-ID: Subject: Re: [PATCH 4/6] Watchdog: introdouce "pretimeout" into framework From: Fu Wei To: Guenter Roeck Cc: Suravee Suthikulpanit , Linaro ACPI Mailman List , linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Wei Fu , G Gregory , Al Stone , Hanjun Guo , Timur Tabi , Ashwin Chaugule , Arnd Bergmann , vgandhi@codeaurora.org, wim@iguana.be, Jon Masters , Leo Duran , Jon Corbet Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Guenter, Great thanks for your review, feedback inline below :-) On 15 May 2015 at 21:33, Guenter Roeck wrote: > On 05/15/2015 04:24 AM, fu.wei@linaro.org wrote: >> >> From: Fu Wei >> >> Reasons: >> (1)kernel already has two watchdog drivers are using "pretimeout": >> drivers/char/ipmi/ipmi_watchdog.c >> drivers/watchdog/kempld_wdt.c(but the definition is different) >> (2)some other dirvers are going to use this: ARM SBSA Generic Watchdog >> >> Signed-off-by: Fu Wei >> --- >> drivers/watchdog/watchdog_core.c | 66 >> ++++++++++++++++++++++++++++++++++++++++ >> drivers/watchdog/watchdog_dev.c | 48 +++++++++++++++++++++++++++++ >> include/linux/watchdog.h | 19 ++++++++++++ >> 3 files changed, 133 insertions(+) >> >> diff --git a/drivers/watchdog/watchdog_core.c >> b/drivers/watchdog/watchdog_core.c >> index cec9b55..6ca9578 100644 >> --- a/drivers/watchdog/watchdog_core.c >> +++ b/drivers/watchdog/watchdog_core.c >> @@ -54,6 +54,14 @@ static void watchdog_check_min_max_timeout(struct >> watchdog_device *wdd) >> wdd->min_timeout = 0; >> wdd->max_timeout = 0; >> } >> + if (wdd->min_pretimeout && wdd->min_timeout < wdd->min_pretimeout) >> { >> + pr_info("Invalid min timeout, resetting to min >> pretimeout!\n"); >> + wdd->min_timeout = wdd->min_pretimeout; >> + } >> + if (wdd->max_pretimeout && wdd->max_timeout < wdd->max_pretimeout) >> { >> + pr_info("Invalid max timeout, resetting to max >> pretimeout!\n"); >> + wdd->max_timeout = wdd->max_pretimeout; >> + } > > > I am a bit concerned about the context dependency introduced here. If > someone calls > _init_pretimeout after calling init_timeout, this may result in still > invalid timeout > values. yes, that logic is not very clean, so my thought is : maybe we can integrate watchdog_init_timeout and watchdog_init_pretimeout, if maintainer agree to add pretimeout into framework. > > >> } >> >> /** >> @@ -98,6 +106,63 @@ int watchdog_init_timeout(struct watchdog_device *wdd, >> } >> EXPORT_SYMBOL_GPL(watchdog_init_timeout); >> >> +static void watchdog_check_min_max_pretimeout(struct watchdog_device >> *wdd) >> +{ >> + /* >> + * Check that we have valid min and max pretimeout values, if >> + * not reset them both to 0 (=not used or unknown) >> + */ >> + if (wdd->min_pretimeout > wdd->max_pretimeout) { >> + pr_info("Invalid min and max pretimeout, resetting to >> 0!\n"); >> + wdd->min_pretimeout = 0; >> + wdd->max_pretimeout = 0; >> + } >> +} >> + >> +/** >> + * watchdog_init_pretimeout() - initialize the pretimeout field >> + * @pretimeout_parm: pretimeout module parameter >> + * @dev: Device that stores the timeout-sec property >> + * >> + * Initialize the pretimeout field of the watchdog_device struct with >> either >> + * the pretimeout module parameter (if it is valid value) or the >> timeout-sec >> + * property (only if it is a valid value and the timeout_parm is out of >> bounds). >> + * If none of them are valid then we keep the old value (which should >> normally >> + * be the default pretimeout value. >> + * >> + * A zero is returned on success and -EINVAL for failure. >> + */ > > > The new API function also needs to be documented in > Documentation/watchdog/watchdog-kernel-api.txt. good point, thanks will do > >> +int watchdog_init_pretimeout(struct watchdog_device *wdd, >> + unsigned int pretimeout_parm, struct device >> *dev) >> +{ >> + int ret = 0; >> + u32 timeouts[2]; >> + >> + watchdog_check_min_max_pretimeout(wdd); >> + >> + /* try to get the timeout module parameter first */ >> + if (!watchdog_pretimeout_invalid(wdd, pretimeout_parm) && >> + pretimeout_parm) { >> + wdd->pretimeout = pretimeout_parm; >> + return ret; >> + } >> + if (pretimeout_parm) >> + ret = -EINVAL; >> + >> + /* try to get the timeout_sec property */ >> + if (!dev || !dev->of_node) >> + return ret; >> + ret = of_property_read_u32_array(dev->of_node, >> + "timeout-sec", timeouts, 2); >> + if (!watchdog_pretimeout_invalid(wdd, timeouts[1]) && timeouts[1]) > > > Guess we are still waiting for feedback from the devicetree maintainers on > this. yes! > > Both the above synchronization concern and this makes me wonder if we should > introduce > watchdog_init_timeouts() instead, which would take pretimeout as additional > parameter. > What do you think about that ? yes, that is what I am thinking about > > >> + wdd->pretimeout = timeouts[1]; >> + else >> + ret = -EINVAL; >> + >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(watchdog_init_pretimeout); >> + >> /** >> * watchdog_register_device() - register a watchdog device >> * @wdd: watchdog device >> @@ -119,6 +184,7 @@ int watchdog_register_device(struct watchdog_device >> *wdd) >> if (wdd->ops->start == NULL || wdd->ops->stop == NULL) >> return -EINVAL; >> >> + watchdog_check_min_max_pretimeout(wdd); >> watchdog_check_min_max_timeout(wdd); >> >> /* >> diff --git a/drivers/watchdog/watchdog_dev.c >> b/drivers/watchdog/watchdog_dev.c >> index 6aaefba..b519257 100644 >> --- a/drivers/watchdog/watchdog_dev.c >> +++ b/drivers/watchdog/watchdog_dev.c >> @@ -218,6 +218,38 @@ out_timeout: >> } >> >> /* >> + * watchdog_set_pretimeout: set the watchdog timer pretimeout >> + * @wddev: the watchdog device to set the timeout for >> + * @pretimeout: pretimeout to set in seconds >> + */ >> + >> +static int watchdog_set_pretimeout(struct watchdog_device *wddev, >> + unsigned int pretimeout) >> +{ >> + int err; >> + >> + if (!wddev->ops->set_pretimeout || >> + !(wddev->info->options & WDIOF_PRETIMEOUT)) >> + return -EOPNOTSUPP; >> + >> + if (watchdog_pretimeout_invalid(wddev, pretimeout)) >> + return -EINVAL; >> + >> + mutex_lock(&wddev->lock); >> + >> + if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { >> + err = -ENODEV; >> + goto out_pretimeout; >> + } >> + >> + err = wddev->ops->set_pretimeout(wddev, pretimeout); >> + >> +out_pretimeout: >> + mutex_unlock(&wddev->lock); >> + return err; >> +} >> + >> +/* >> * watchdog_get_timeleft: wrapper to get the time left before a >> reboot >> * @wddev: the watchdog device to get the remaining time from >> * @timeleft: the time that's left >> @@ -388,6 +420,22 @@ static long watchdog_ioctl(struct file *file, >> unsigned int cmd, >> if (wdd->timeout == 0) >> return -EOPNOTSUPP; >> return put_user(wdd->timeout, p); >> + case WDIOC_SETPRETIMEOUT: >> + if (get_user(val, p)) >> + return -EFAULT; >> + err = watchdog_set_pretimeout(wdd, val); >> + if (err < 0) >> + return err; >> + /* If the watchdog is active then we send a keepalive ping >> + * to make sure that the watchdog keep's running (and if > > > s/keep's/keeps/ Great thanks, typo > >> + * possible that it takes the new timeout) */ > > > Please use the common multi-line comment style (that it isn't used above is > not > an argument). yes, my bad, will fixed . > > >> + watchdog_ping(wdd); >> + /* Fall */ >> + case WDIOC_GETPRETIMEOUT: >> + /* timeout == 0 means that we don't use the pretimeout */ >> + if (wdd->pretimeout == 0) >> + return -EOPNOTSUPP; >> + return put_user(wdd->pretimeout, p); >> case WDIOC_GETTIMELEFT: >> err = watchdog_get_timeleft(wdd, &val); >> if (err) >> diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h >> index a746bf5..f0a3c5b 100644 >> --- a/include/linux/watchdog.h >> +++ b/include/linux/watchdog.h >> @@ -25,6 +25,7 @@ struct watchdog_device; >> * @ping: The routine that sends a keepalive ping to the watchdog >> device. >> * @status: The routine that shows the status of the watchdog device. >> * @set_timeout:The routine for setting the watchdog devices timeout >> value. >> + * @set_pretimeout:The routine for setting the watchdog devices >> pretimeout value >> * @get_timeleft:The routine that get's the time that's left before a >> reset. >> * @ref: The ref operation for dyn. allocated watchdog_device >> structs >> * @unref: The unref operation for dyn. allocated watchdog_device >> structs >> @@ -44,6 +45,7 @@ struct watchdog_ops { >> int (*ping)(struct watchdog_device *); >> unsigned int (*status)(struct watchdog_device *); >> int (*set_timeout)(struct watchdog_device *, unsigned int); >> + int (*set_pretimeout)(struct watchdog_device *, unsigned int); >> unsigned int (*get_timeleft)(struct watchdog_device *); >> void (*ref)(struct watchdog_device *); >> void (*unref)(struct watchdog_device *); >> @@ -62,6 +64,9 @@ struct watchdog_ops { >> * @timeout: The watchdog devices timeout value. >> * @min_timeout:The watchdog devices minimum timeout value. >> * @max_timeout:The watchdog devices maximum timeout value. >> + * @pretimeout: The watchdog devices pretimeout value. >> + * @min_pretimeout:The watchdog devices minimum pretimeout value. >> + * @max_pretimeout:The watchdog devices maximum pretimeout value. >> * @driver-data:Pointer to the drivers private data. >> * @lock: Lock for watchdog core internal use only. >> * @status: Field that contains the devices internal status bits. >> @@ -86,6 +91,9 @@ struct watchdog_device { >> unsigned int timeout; >> unsigned int min_timeout; >> unsigned int max_timeout; >> + unsigned int pretimeout; >> + unsigned int min_pretimeout; >> + unsigned int max_pretimeout; >> void *driver_data; >> struct mutex lock; >> unsigned long status; >> @@ -120,6 +128,14 @@ static inline bool watchdog_timeout_invalid(struct >> watchdog_device *wdd, unsigne >> (t < wdd->min_timeout || t > wdd->max_timeout)); >> } >> >> +/* Use the following function to check if a pretimeout value is invalid >> */ >> +static inline bool watchdog_pretimeout_invalid(struct watchdog_device >> *wdd, >> + unsigned int t) >> +{ >> + return ((wdd->max_pretimeout != 0) && >> + (t < wdd->min_pretimeout || t > wdd->max_pretimeout)); >> +} >> + >> /* Use the following functions to manipulate watchdog driver specific >> data */ >> static inline void watchdog_set_drvdata(struct watchdog_device *wdd, >> void *data) >> { >> @@ -134,6 +150,9 @@ static inline void *watchdog_get_drvdata(struct >> watchdog_device *wdd) >> /* drivers/watchdog/watchdog_core.c */ >> extern int watchdog_init_timeout(struct watchdog_device *wdd, >> unsigned int timeout_parm, struct device >> *dev); >> +extern int watchdog_init_pretimeout(struct watchdog_device *wdd, >> + unsigned int pretimeout_parm, >> + struct device *dev); > > > Please drop the 'extern'. Guess it may be time to clean up the watchdog core > code ;-). yes, you are right, but in different patchset ?? > > Thanks, > Guenter > -- Best regards, Fu Wei Software Engineer Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch Ph: +86 21 61221326(direct) Ph: +86 186 2020 4684 (mobile) Room 1512, Regus One Corporate Avenue,Level 15, One Corporate Avenue,222 Hubin Road,Huangpu District, Shanghai,China 200021