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authorJohn Hubbard <jhubbard@nvidia.com>2014-04-07 15:37:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 16:35:59 -0700
commited12d845b5f528cc0846023862b9c448a36122ec (patch)
tree37e1fde944c5c1d62ed780abd32ac52846672365 /mm
parent834a964a098e7726fc296d7cd8f65ed3eeedd412 (diff)
downloadlinux-ed12d845b5f528cc0846023862b9c448a36122ec.tar.bz2
mm/page_alloc.c: change mm debug routines back to EXPORT_SYMBOL
A new dump_page() routine was recently added, and marked EXPORT_SYMBOL_GPL. dump_page() was also added to the VM_BUG_ON_PAGE() macro, and so the end result is that non-GPL code can no longer call get_page() and a few other routines. This only happens if the kernel was compiled with CONFIG_DEBUG_VM. Change dump_page() to be EXPORT_SYMBOL. Longer explanation: Prior to commit 309381feaee5 ("mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE") , it was possible to build MIT-licensed (non-GPL) drivers on Fedora. Fedora is semi-unique, in that it sets CONFIG_VM_DEBUG. Because Fedora sets CONFIG_VM_DEBUG, they end up pulling in dump_page(), via VM_BUG_ON_PAGE, via get_page(). As one of the authors of NVIDIA's new, open source, "UVM-Lite" kernel module, I originally choose to use the kernel's get_page() routine from within nvidia_uvm_page_cache.c, because get_page() has always seemed to be very clearly intended for use by non-GPL, driver code. So I'm hoping that making get_page() widely accessible again will not be too controversial. We did check with Fedora first, and they responded (https://bugzilla.redhat.com/show_bug.cgi?id=1074710#c3) that we should try to get upstream changed, before asking Fedora to change. Their reasoning seems beneficial to Linux: leaving CONFIG_DEBUG_VM set allows Fedora to help catch mm bugs. Signed-off-by: John Hubbard <jhubbard@nvidia.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Josh Boyer <jwboyer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 48427a7cfb45..5dba2933c9c0 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6568,4 +6568,4 @@ void dump_page(struct page *page, const char *reason)
{
dump_page_badflags(page, reason, 0);
}
-EXPORT_SYMBOL_GPL(dump_page);
+EXPORT_SYMBOL(dump_page);