From: David Brownell Date: Sat, 25 Nov 2006 19:09:28 +0000 (-0800) Subject: [PATCH] rtc class locking bugfixes X-Git-Tag: v2.6.19~39 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=d728b1e69fd5829ec2ab2434381e5a268d4f684a;p=linux-2.6-omap-h63xx.git [PATCH] rtc class locking bugfixes I got a lockdep warning when running "rtctest" so I though it'd be good to see what was up. - The warning was for rtc->irq_task_lock, gotten from rtc_update_irq() by irq handlerss ... but in a handful of other cases, grabbed without blocking IRQs. - Some callers to rtc_update_irq() were not ensuring IRQs were blocked, yet the routine expects that; make sure all callers block IRQs. It would appear that RTC API tests haven't been part of anyone's kernel regression test suite recently, at least not with lockdep running. Signed-off-by: David Brownell Acked-by: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 4783ec68fb3..6f11f6dfdd9 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -145,6 +145,13 @@ int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm) } EXPORT_SYMBOL_GPL(rtc_set_alarm); +/** + * rtc_update_irq - report RTC periodic, alarm, and/or update irqs + * @class_dev: the rtc's class device + * @num: how many irqs are being reported (usually one) + * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF + * Context: in_interrupt(), irqs blocked + */ void rtc_update_irq(struct class_device *class_dev, unsigned long num, unsigned long events) { @@ -201,12 +208,12 @@ int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task) if (task == NULL || task->func == NULL) return -EINVAL; - spin_lock(&rtc->irq_task_lock); + spin_lock_irq(&rtc->irq_task_lock); if (rtc->irq_task == NULL) { rtc->irq_task = task; retval = 0; } - spin_unlock(&rtc->irq_task_lock); + spin_unlock_irq(&rtc->irq_task_lock); return retval; } @@ -216,10 +223,10 @@ void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task) { struct rtc_device *rtc = to_rtc_device(class_dev); - spin_lock(&rtc->irq_task_lock); + spin_lock_irq(&rtc->irq_task_lock); if (rtc->irq_task == task) rtc->irq_task = NULL; - spin_unlock(&rtc->irq_task_lock); + spin_unlock_irq(&rtc->irq_task_lock); } EXPORT_SYMBOL_GPL(rtc_irq_unregister); diff --git a/drivers/rtc/rtc-at91.c b/drivers/rtc/rtc-at91.c index bd61e99540a..5c8addcaf1f 100644 --- a/drivers/rtc/rtc-at91.c +++ b/drivers/rtc/rtc-at91.c @@ -292,7 +292,8 @@ static int __init at91_rtc_probe(struct platform_device *pdev) AT91_RTC_CALEV); ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt, - IRQF_SHARED, "at91_rtc", pdev); + IRQF_DISABLED | IRQF_SHARED, + "at91_rtc", pdev); if (ret) { printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n", AT91_ID_SYS); diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c index 3109865e8d7..814b9e1873f 100644 --- a/drivers/rtc/rtc-dev.c +++ b/drivers/rtc/rtc-dev.c @@ -61,7 +61,9 @@ static void rtc_uie_task(void *data) int err; err = rtc_read_time(&rtc->class_dev, &tm); - spin_lock_irq(&rtc->irq_lock); + + local_irq_disable(); + spin_lock(&rtc->irq_lock); if (rtc->stop_uie_polling || err) { rtc->uie_task_active = 0; } else if (rtc->oldsecs != tm.tm_sec) { @@ -74,11 +76,11 @@ static void rtc_uie_task(void *data) } else if (schedule_work(&rtc->uie_task) == 0) { rtc->uie_task_active = 0; } - spin_unlock_irq(&rtc->irq_lock); + spin_unlock(&rtc->irq_lock); if (num) rtc_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF); + local_irq_enable(); } - static void rtc_uie_timer(unsigned long data) { struct rtc_device *rtc = (struct rtc_device *)data; @@ -238,10 +240,10 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file, /* avoid conflicting IRQ users */ if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) { - spin_lock(&rtc->irq_task_lock); + spin_lock_irq(&rtc->irq_task_lock); if (rtc->irq_task) err = -EBUSY; - spin_unlock(&rtc->irq_task_lock); + spin_unlock_irq(&rtc->irq_task_lock); if (err < 0) return err; diff --git a/drivers/rtc/rtc-ds1553.c b/drivers/rtc/rtc-ds1553.c index 78552e6e76a..001eb1123a6 100644 --- a/drivers/rtc/rtc-ds1553.c +++ b/drivers/rtc/rtc-ds1553.c @@ -340,7 +340,8 @@ static int __init ds1553_rtc_probe(struct platform_device *pdev) if (pdata->irq >= 0) { writeb(0, ioaddr + RTC_INTERRUPTS); - if (request_irq(pdata->irq, ds1553_rtc_interrupt, IRQF_SHARED, + if (request_irq(pdata->irq, ds1553_rtc_interrupt, + IRQF_DISABLED | IRQF_SHARED, pdev->name, pdev) < 0) { dev_warn(&pdev->dev, "interrupt not available.\n"); pdata->irq = -1; diff --git a/drivers/rtc/rtc-test.c b/drivers/rtc/rtc-test.c index bc4bd24508a..6ef9c62d503 100644 --- a/drivers/rtc/rtc-test.c +++ b/drivers/rtc/rtc-test.c @@ -99,6 +99,7 @@ static ssize_t test_irq_store(struct device *dev, struct rtc_device *rtc = platform_get_drvdata(plat_dev); retval = count; + local_irq_disable(); if (strncmp(buf, "tick", 4) == 0) rtc_update_irq(&rtc->class_dev, 1, RTC_PF | RTC_IRQF); else if (strncmp(buf, "alarm", 5) == 0) @@ -107,6 +108,7 @@ static ssize_t test_irq_store(struct device *dev, rtc_update_irq(&rtc->class_dev, 1, RTC_UF | RTC_IRQF); else retval = -EINVAL; + local_irq_enable(); return retval; }