@@ -1614,11 +1614,13 @@ static inline void put_page(struct page *page)
#define GUP_PIN_COUNTING_BIAS (1U << 10)
void unpin_user_page(struct page *page);
+void unpin_folio(struct folio *folio);
void unpin_user_pages_dirty_lock(struct page **pages, unsigned long npages,
bool make_dirty);
void unpin_user_page_range_dirty_lock(struct page *page, unsigned long npages,
bool make_dirty);
void unpin_user_pages(struct page **pages, unsigned long npages);
+void unpin_folios(struct folio **folios, unsigned long nfolios);
static inline bool is_cow_mapping(vm_flags_t flags)
{
@@ -276,6 +276,19 @@ void unpin_user_page(struct page *page)
}
EXPORT_SYMBOL(unpin_user_page);
+/**
+ * unpin_folio() - release a dma-pinned folio
+ * @folio: pointer to folio to be released
+ *
+ * Folios that were pinned via memfd_pin_folios() or other similar routines
+ * must be released either using unpin_folio() or unpin_folios().
+ */
+void unpin_folio(struct folio *folio)
+{
+ gup_put_folio(folio, 1, FOLL_PIN);
+}
+EXPORT_SYMBOL_GPL(unpin_folio);
+
/**
* folio_add_pin - Try to get an additional pin on a pinned folio
* @folio: The folio to be pinned
@@ -488,6 +501,40 @@ void unpin_user_pages(struct page **pages, unsigned long npages)
}
EXPORT_SYMBOL(unpin_user_pages);
+/**
+ * unpin_folios() - release an array of gup-pinned folios.
+ * @folios: array of folios to be marked dirty and released.
+ * @nfolios: number of folios in the @folios array.
+ *
+ * For each folio in the @folios array, release the folio using gup_put_folio.
+ *
+ * Please see the unpin_folio() documentation for details.
+ */
+void unpin_folios(struct folio **folios, unsigned long nfolios)
+{
+ unsigned long i = 0, j;
+
+ /*
+ * If this WARN_ON() fires, then the system *might* be leaking folios
+ * (by leaving them pinned), but probably not. More likely, gup/pup
+ * returned a hard -ERRNO error to the caller, who erroneously passed
+ * it here.
+ */
+ if (WARN_ON(IS_ERR_VALUE(nfolios)))
+ return;
+
+ while (i < nfolios) {
+ for (j = i + 1; j < nfolios; j++)
+ if (folios[i] != folios[j])
+ break;
+
+ if (folios[i])
+ gup_put_folio(folios[i], j - i, FOLL_PIN);
+ i = j;
+ }
+}
+EXPORT_SYMBOL_GPL(unpin_folios);
+
/*
* Set the MMF_HAS_PINNED if not set yet; after set it'll be there for the mm's
* lifecycle. Avoid setting the bit unless necessary, or it might cause write
These helpers are the folio versions of unpin_user_page/unpin_user_pages. They are currently only useful for unpinning folios pinned by memfd_pin_folios() or other associated routines. However, they could find new uses in the future, when more and more folio-only helpers are added to GUP. We should probably sanity check the folio as part of unpin similar to how it is done in unpin_user_page/unpin_user_pages but we cannot cleanly do that at the moment without also checking the subpage. Therefore, sanity checking needs to be added to these routines once we have a way to determine if any given folio is anon-exclusive (via a per folio AnonExclusive flag). Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com> --- include/linux/mm.h | 2 ++ mm/gup.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+)