On Tue, Jan 03, 2017 at 09:31:18PM +0000, Russell King - ARM Linux wrote: > On Tue, Jan 03, 2017 at 01:18:29PM -0800, Kees Cook wrote: > > On Mon, Jan 2, 2017 at 6:06 AM, Russell King - ARM Linux > > <li...@armlinux.org.uk> wrote: > > > On Mon, Dec 26, 2016 at 05:01:02PM +0530, Bhumika Goyal wrote: > > >> The object armada38x_rtc_ops of type rtc_class_ops structure is not > > >> modified after getting initialized by armada38x_rtc_probe. Apart from > > >> getting referenced in init it is also passed as an argument to the > > >> function > > >> devm_rtc_device_register but this argument is of type const struct > > >> rtc_class_ops *. Therefore add __ro_after_init to its declaration. > > > > > > What I'd prefer here is for the structure to be duplicated, with one > > > copy having the alarm methods and one which does not. Both can then > > > be made "const" (so placed into the read-only section at link time) > > > and the probe function select between the two. > > > > > > I think that's a cleaner and better solution, even though it's > > > slightly larger. > > > > > > I'm not a fan of __ro_after_init being used where other solutions are > > > possible. > > > > Can the pointer that points to the struct rtc_class_ops be made > > ro_after_init? > > It's passed into the RTC core code, and probably stored in some dynamically > allocated object, so probably no. It's the same class of problem as every > file_operations pointer in the kernel, or the thousand other operations > structure pointers that a running kernel has.
For the elimination of doubt, this is what I meant in my original email. As you can see, there's nothing to be marked as __ro_after_init anymore. drivers/rtc/rtc-armada38x.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index 9a3f2a6f512e..a4166ccfce36 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -202,7 +202,7 @@ static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data) return IRQ_HANDLED; } -static struct rtc_class_ops armada38x_rtc_ops = { +static const struct rtc_class_ops armada38x_rtc_ops = { .read_time = armada38x_rtc_read_time, .set_time = armada38x_rtc_set_time, .read_alarm = armada38x_rtc_read_alarm, @@ -210,8 +210,15 @@ static struct rtc_class_ops armada38x_rtc_ops = { .alarm_irq_enable = armada38x_rtc_alarm_irq_enable, }; +static const struct rtc_class_ops armada38x_rtc_ops_noirq = { + .read_time = armada38x_rtc_read_time, + .set_time = armada38x_rtc_set_time, + .read_alarm = armada38x_rtc_read_alarm, +}; + static __init int armada38x_rtc_probe(struct platform_device *pdev) { + const struct rtc_class_ops *ops; struct resource *res; struct armada38x_rtc *rtc; int ret; @@ -242,19 +249,22 @@ static __init int armada38x_rtc_probe(struct platform_device *pdev) 0, pdev->name, rtc) < 0) { dev_warn(&pdev->dev, "Interrupt not available.\n"); rtc->irq = -1; + } + platform_set_drvdata(pdev, rtc); + + if (rtc->irq != -1) { + device_init_wakeup(&pdev->dev, 1); + ops = &armada38x_rtc_ops; + } else { /* * If there is no interrupt available then we can't * use the alarm */ - armada38x_rtc_ops.set_alarm = NULL; - armada38x_rtc_ops.alarm_irq_enable = NULL; + ops = &armada38x_rtc_ops_noirq; } - platform_set_drvdata(pdev, rtc); - if (rtc->irq != -1) - device_init_wakeup(&pdev->dev, 1); rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, - &armada38x_rtc_ops, THIS_MODULE); + ops, THIS_MODULE); if (IS_ERR(rtc->rtc_dev)) { ret = PTR_ERR(rtc->rtc_dev); dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret); -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- 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+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.