Re: [PATCH v2 14/16] rtc: utilize new cdev_device_add helper function
From: Alexandre Belloni <hidden>
Date: 2017-02-27 09:46:43
Also in:
linux-fsdevel, linux-gpio, linux-rdma, linux-rtc, linux-scsi, nvdimm
Possibly related (same subject, not in this thread)
- 2017-02-26 · [PATCH v2 14/16] rtc: utilize new cdev_device_add helper function · Logan Gunthorpe <hidden>
On 25/02/2017 at 23:38:15 -0700, Logan Gunthorpe wrote:
Mostly straightforward, but we had to remove the rtc_dev_add/del_device functions as they split up the cdev_add and the device_add. Doing this also revealed that there was likely another subtle bug: seeing cdev_add was done after device_register, the cdev probably was not ready before device_add when the uevent occurs. This would race with userspace, if it tried to use the device directly after the uevent. This is fixed just by using the new helper function. Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
Acked-by: Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
quoted hunk
--- drivers/rtc/class.c | 14 ++++++++++---- drivers/rtc/rtc-dev.c | 17 ----------------- 2 files changed, 10 insertions(+), 21 deletions(-)diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 74fd974..5fb4398 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c@@ -195,6 +195,8 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, goto exit_ida; } + device_initialize(&rtc->dev); + rtc->id = id; rtc->ops = ops; rtc->owner = owner;@@ -233,14 +235,19 @@ struct rtc_device *rtc_device_register(const char *name, struct device *dev, rtc_dev_prepare(rtc); - err = device_register(&rtc->dev); + err = cdev_device_add(&rtc->char_dev, &rtc->dev); if (err) { + dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", + rtc->name, MAJOR(rtc->dev.devt), rtc->id); + /* This will free both memory and the ID */ put_device(&rtc->dev); goto exit; + } else { + dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name, + MAJOR(rtc->dev.devt), rtc->id); } - rtc_dev_add_device(rtc); rtc_proc_add_device(rtc); dev_info(dev, "rtc core: registered %s as %s\n",@@ -271,9 +278,8 @@ void rtc_device_unregister(struct rtc_device *rtc) * Remove innards of this RTC, then disable it, before * letting any rtc_class_open() users access it again */ - rtc_dev_del_device(rtc); rtc_proc_del_device(rtc); - device_del(&rtc->dev); + cdev_device_del(&rtc->char_dev, &rtc->dev); rtc->ops = NULL; mutex_unlock(&rtc->ops_lock); put_device(&rtc->dev);diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c index a6d9434..fdd071f 100644 --- a/drivers/rtc/rtc-dev.c +++ b/drivers/rtc/rtc-dev.c@@ -477,23 +477,6 @@ void rtc_dev_prepare(struct rtc_device *rtc) cdev_init(&rtc->char_dev, &rtc_dev_fops); rtc->char_dev.owner = rtc->owner; - rtc->char_dev.kobj.parent = &rtc->dev.kobj; -} - -void rtc_dev_add_device(struct rtc_device *rtc) -{ - if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1)) - dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", - rtc->name, MAJOR(rtc_devt), rtc->id); - else - dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name, - MAJOR(rtc_devt), rtc->id); -} - -void rtc_dev_del_device(struct rtc_device *rtc) -{ - if (rtc->dev.devt) - cdev_del(&rtc->char_dev); } void __init rtc_dev_init(void)-- 2.1.4
-- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. --- You received this message because you are subscribed to the Google Groups "rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to rtc-linux+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit https://groups.google.com/d/optout.