[rtc-linux] Re: [PATCH] rtc: armada38x: add __ro_after_init to armada38x_rtc_ops
From: Russell King - ARM Linux <linux@armlinux.org.uk>
Date: 2017-01-03 21:32:24
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linux-arm-kernel, lkml
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 [off-list ref] wrote:quoted
On Mon, Dec 26, 2016 at 05:01:02PM +0530, Bhumika Goyal wrote:quoted
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. -- 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+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.