[PATCH] A long explanation for a short patch

[john.hubbard@gmail.com]

From: John Hubbard <jhubbard@nvidia.com>

Hi Sasha and linux-mm,

Prior to commit 309381feaee564281c3d9e90fbca8963bb7428ad, 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.

thanks,
John h

John Hubbard (1):
  Change mm debug routines back to EXPORT_SYMBOL

 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
1.9.0

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