mm/hugetlb: remove hugetlb_follow_page_mask() leftover

We removed hugetlb_follow_page_mask() in commit 9cb28da54643 ("mm/gup:
handle hugetlb in the generic follow_page_mask code") but forgot to
cleanup some leftovers.

While at it, simplify the hugetlb comment, it's overly detailed and rather
confusing.  Stating that we may end up in there during coredumping is
sufficient to explain the PF_DUMPCORE usage.

Link: https://lkml.kernel.org/r/20240731142000.625044-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index b3ed7207df7e393a62d86f4907ce851e9f1df9da..68cdd89c97a3f91042cbbed588964f2402fe6864 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -371,15 +371,8 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
        unsigned int blocking_state;
 
        /*
-        * We don't do userfault handling for the final child pid update.
-        *
-        * We also don't do userfault handling during
-        * coredumping. hugetlbfs has the special
-        * hugetlb_follow_page_mask() to skip missing pages in the
-        * FOLL_DUMP case, anon memory also checks for FOLL_DUMP with
-        * the no_page_table() helper in follow_page_mask(), but the
-        * shmem_vm_ops->fault method is invoked even during
-        * coredumping and it ends up here.
+        * We don't do userfault handling for the final child pid update
+        * and when coredumping (faults triggered by get_dump_page()).
         */
        if (current->flags & (PF_EXITING|PF_DUMPCORE))
                goto out;

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 9b7bcfce692055eb9991c627dbf9b7a47eb45419..3100a52ceb735a9a94da02cb48f25d9409daa2e6 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -127,9 +127,6 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma,
                             unsigned long len);
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *,
                            struct vm_area_struct *, struct vm_area_struct *);
-struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma,
-                                     unsigned long address, unsigned int flags,
-                                     unsigned int *page_mask);
 void unmap_hugepage_range(struct vm_area_struct *,
                          unsigned long, unsigned long, struct page *,
                          zap_flags_t);