On Mon, Jun 03, 2019 at 04:56:10PM -0700, Ira Weiny wrote:
> On Mon, Jun 03, 2019 at 09:42:06AM -0700, Christoph Hellwig wrote:
> > > +#if defined(CONFIG_CMA)
> >
> > You can just use #ifdef here.
> >
> > > +static inline int reject_cma_pages(int nr_pinned, unsigned int gup_flags,
> > > + struct page **pages)
> >
> > Please use two instead of one tab to indent the continuing line of
> > a function declaration.
> >
> > > +{
> > > + if (unlikely(gup_flags & FOLL_LONGTERM)) {
> >
> > IMHO it would be a little nicer if we could move this into the caller.
>
> FWIW we already had this discussion and thought it better to put this here.
>
> https://lkml.org/lkml/2019/5/30/1565
I don't see any discussion like this. FYI, this is what I mean,
code might be easier than words:
diff --git a/mm/gup.c b/mm/gup.c
index ddde097cf9e4..62d770b18e2c 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2197,6 +2197,27 @@ static int __gup_longterm_unlocked(unsigned long start, int nr_pages,
return ret;
}
+#ifdef CONFIG_CMA
+static int reject_cma_pages(struct page **pages, int nr_pinned)
+{
+ int i = 0;
+
+ for (i = 0; i < nr_pinned; i++)
+ if (is_migrate_cma_page(pages[i])) {
+ put_user_pages(pages + i, nr_pinned - i);
+ return i;
+ }
+ }
+
+ return nr_pinned;
+}
+#else
+static inline int reject_cma_pages(struct page **pages, int nr_pinned)
+{
+ return nr_pinned;
+}
+#endif /* CONFIG_CMA */
+
/**
* get_user_pages_fast() - pin user pages in memory
* @start: starting user address
@@ -2237,6 +2258,9 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
ret = nr;
}
+ if (nr && unlikely(gup_flags & FOLL_LONGTERM))
+ nr = reject_cma_pages(pages, nr);
+
if (nr < nr_pages) {
/* Try to get the remaining pages with get_user_pages */
start += nr << PAGE_SHIFT;
