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authorAxel Rasmussen <axelrasmussen@google.com>2021-05-05 04:35:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 21:27:22 +0300
commit714c189108244f1df579689061db1d785d92e7e2 (patch)
tree8b1be718a88d9741e32b693fd722107d2f3de91e /mm/hugetlb.c
parent0d9cadabd193c6008d256533f544de8206fd3a80 (diff)
downloadlinux-714c189108244f1df579689061db1d785d92e7e2.tar.xz
userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled
For background, mm/userfaultfd.c provides a general mcopy_atomic implementation. But some types of memory (i.e., hugetlb and shmem) need a slightly different implementation, so they provide their own helpers for this. In other words, userfaultfd is the only caller of these functions. This patch achieves two things: 1. Don't spend time compiling code which will end up never being referenced anyway (a small build time optimization). 2. In patches later in this series, we extend the signature of these helpers with UFFD-specific state (a mode enumeration). Once this happens, we *have to* either not compile the helpers, or unconditionally define the UFFD-only state (which seems messier to me). This includes the declarations in the headers, as otherwise they'd yield warnings about implicitly defining the type of those arguments. Link: https://lkml.kernel.org/r/20210301222728.176417-4-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Adam Ruprecht <ruprecht@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Cannon Matthews <cannonmatthews@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chinwen Chang <chinwen.chang@mediatek.com> Cc: David Rientjes <rientjes@google.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Michal Koutn" <mkoutny@suse.com> Cc: Michel Lespinasse <walken@google.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oliver Upton <oupton@google.com> Cc: Shaohua Li <shli@fb.com> Cc: Shawn Anastasio <shawn@anastas.io> Cc: Steven Price <steven.price@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 84530876b2ae..b105a455124d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4855,6 +4855,7 @@ out_mutex:
return ret;
}
+#ifdef CONFIG_USERFAULTFD
/*
* Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
* modifications for huge pages.
@@ -4985,6 +4986,7 @@ out_release_nounlock:
put_page(page);
goto out;
}
+#endif /* CONFIG_USERFAULTFD */
static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma,
int refs, struct page **pages,