@@ -284,13 +284,18 @@ static inline void clear_highpage(struct page *page)
kunmap_atomic(kaddr);
}
+#if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2);
+#else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
static inline void zero_user_segments(struct page *page,
- unsigned start1, unsigned end1,
- unsigned start2, unsigned end2)
+ unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2)
{
void *kaddr = kmap_atomic(page);
+ unsigned int i;
- BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
+ BUG_ON(end1 > thp_size(page) || end2 > thp_size(page));
if (end1 > start1)
memset(kaddr + start1, 0, end1 - start1);
@@ -299,8 +304,10 @@ static inline void zero_user_segments(struct page *page,
memset(kaddr + start2, 0, end2 - start2);
kunmap_atomic(kaddr);
- flush_dcache_page(page);
+ for (i = 0; i < thp_nr_pages(page); i++)
+ flush_dcache_page(page + i);
}
+#endif /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */
static inline void zero_user_segment(struct page *page,
unsigned start, unsigned end)
@@ -367,9 +367,67 @@ void kunmap_high(struct page *page)
if (need_wakeup)
wake_up(pkmap_map_wait);
}
-
EXPORT_SYMBOL(kunmap_high);
-#endif
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2)
+{
+ unsigned int i;
+
+ BUG_ON(end1 > thp_size(page) || end2 > thp_size(page));
+
+ for (i = 0; i < thp_nr_pages(page); i++) {
+ void *kaddr;
+ unsigned this_end;
+
+ if (end1 == 0 && start2 >= PAGE_SIZE) {
+ start2 -= PAGE_SIZE;
+ end2 -= PAGE_SIZE;
+ continue;
+ }
+
+ if (start1 >= PAGE_SIZE) {
+ start1 -= PAGE_SIZE;
+ end1 -= PAGE_SIZE;
+ if (start2) {
+ start2 -= PAGE_SIZE;
+ end2 -= PAGE_SIZE;
+ }
+ continue;
+ }
+
+ kaddr = kmap_atomic(page + i);
+
+ this_end = min_t(unsigned, end1, PAGE_SIZE);
+ if (end1 > start1)
+ memset(kaddr + start1, 0, this_end - start1);
+ end1 -= this_end;
+ start1 = 0;
+
+ if (start2 >= PAGE_SIZE) {
+ start2 -= PAGE_SIZE;
+ end2 -= PAGE_SIZE;
+ } else {
+ this_end = min_t(unsigned, end2, PAGE_SIZE);
+ if (end2 > start2)
+ memset(kaddr + start2, 0, this_end - start2);
+ end2 -= this_end;
+ start2 = 0;
+ }
+
+ kunmap_atomic(kaddr);
+ flush_dcache_page(page + i);
+
+ if (!end1 && !end2)
+ break;
+ }
+
+ BUG_ON((start1 | start2 | end1 | end2) != 0);
+}
+EXPORT_SYMBOL(zero_user_segments);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif /* CONFIG_HIGHMEM */
#if defined(HASHED_PAGE_VIRTUAL)
We can only kmap() one subpage of a THP at a time, so loop over all relevant subpages, skipping ones which don't need to be zeroed. This is too large to inline when THPs are enabled and we actually need highmem, so put it in highmem.c. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- include/linux/highmem.h | 15 +++++++--- mm/highmem.c | 62 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 71 insertions(+), 6 deletions(-)