On 3/17/26 15:11, Kalyazin, Nikita wrote: > From: Nikita Kalyazin <[email protected]> > > Move the check for pinning closer to where the result is used. > No functional changes. > > Signed-off-by: Nikita Kalyazin <[email protected]> > --- > mm/gup.c | 23 ++++++++++++----------- > 1 file changed, 12 insertions(+), 11 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index 5856d35be385..869d79c8daa4 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -2737,18 +2737,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked); > */ > static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags) > { > - bool reject_file_backed = false; > struct address_space *mapping; > unsigned long mapping_flags; > > - /* > - * If we aren't pinning then no problematic write can occur. A long term > - * pin is the most egregious case so this is the one we disallow. > - */ > - if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) == > - (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) > - reject_file_backed = true; > - > /* We hold a folio reference, so we can safely access folio fields. */ > if (WARN_ON_ONCE(folio_test_slab(folio))) > return false; > @@ -2793,8 +2784,18 @@ static bool gup_fast_folio_allowed(struct folio > *folio, unsigned int flags) > */ > if (secretmem_mapping(mapping)) > return false; > - /* The only remaining allowed file system is shmem. */ > - return !reject_file_backed || shmem_mapping(mapping); > + > + /* > + * If we aren't pinning then no problematic write can occur. A writable > + * long term pin is the most egregious case, so this is the one we > + * allow only for ... > + */ > + if ((flags & (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) != > + (FOLL_PIN | FOLL_LONGTERM | FOLL_WRITE)) > + return true; > + > + /* ... hugetlb (which we allowed above already) and shared memory. */ > + return shmem_mapping(mapping);
Acked-by: David Hildenbrand (Arm) <[email protected]> I'm wondering if it would be a good idea to check for a hugetlb mapping here instead of having the folio_test_hugetlb() check above. Something to ponder about :) -- Cheers, David
