Messages in this thread Patch in this message | | | From | Oleksandr Andrushchenko <> | Subject | [Xen-devel] xen/mem-reservation API and out-of-tree kernel modules | Date | Thu, 31 Jan 2019 14:02:30 +0000 |
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Hello,
I am working on porting an out-of-tree kernel driver to the kernel 5.0 and that driver uses functionality provided by drivers/xen/mem-reservation.c module. Since commit [1] it is not possible to build a kernel module which uses mem-reservation API as xen_scrub_pages variable, which is checked in xenmem_reservation_scrub_page, became a kernel module parameter and is now only accessible for built-in modules:
static inline void xenmem_reservation_scrub_page(struct page *page) ^^^^^^^^^^^^^ { if (xen_scrub_pages) ^^^^^^^^^^^^^^^ clear_highpage(page); }
This results in link-time warning:
WARNING: "xen_scrub_pages" [yourmodule.ko] undefined!
and thus not allowing the module to run. At the moment I can only see a possible fix for this by making the following change:
diff --git a/drivers/xen/mem-reservation.c b/drivers/xen/mem-reservation.c index 3782cf070338..85fecfec50e1 100644 --- a/drivers/xen/mem-reservation.c +++ b/drivers/xen/mem-reservation.c @@ -18,6 +18,7 @@
bool __read_mostly xen_scrub_pages = IS_ENABLED(CONFIG_XEN_SCRUB_PAGES_DEFAULT); core_param(xen_scrub_pages, xen_scrub_pages, bool, 0); +EXPORT_SYMBOL(xen_scrub_pages);
but this looks a bit unusual for the kernel?
I am looking for community advice here and help
Thank you, Oleksandr
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=197ecb3802c04499d8ff4f8cb28f6efa008067db
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