@@ -438,6 +438,65 @@ static void ep_nested_calls_init(struct nested_calls *ncalls)
spin_lock_init(&ncalls->lock);
}
+static inline unsigned int to_items_length(unsigned int nr)
+{
+ struct eventpoll *ep;
+
+ return (sizeof(*ep->user_header) +
+ (nr << ilog2(sizeof(ep->user_header->items[0]))));
+}
+
+static inline unsigned int to_index_length(unsigned int nr)
+{
+ struct eventpoll *ep;
+
+ return nr << ilog2(sizeof(*ep->user_index));
+}
+
+static inline unsigned int to_items_bm_length(unsigned int nr)
+{
+ return ALIGN(nr, 8) >> 3;
+}
+
+static inline unsigned int to_items_nr(unsigned int len)
+{
+ struct eventpoll *ep;
+
+ return (len - sizeof(*ep->user_header)) >>
+ ilog2(sizeof(ep->user_header->items[0]));
+}
+
+static inline unsigned int to_items_bm_nr(unsigned int len)
+{
+ return len << 3;
+}
+
+static inline unsigned int ep_max_items_nr(struct eventpoll *ep)
+{
+ return to_items_nr(ep->header_length);
+}
+
+static inline unsigned int ep_max_index_nr(struct eventpoll *ep)
+{
+ return ep->index_length >> ilog2(sizeof(*ep->user_index));
+}
+
+static inline unsigned int ep_max_items_bm_nr(struct eventpoll *ep)
+{
+ return to_items_bm_nr(ep->items_bm_length);
+}
+
+static inline bool ep_polled_by_user(struct eventpoll *ep)
+{
+ return !!ep->user_header;
+}
+
+static inline bool ep_user_ring_events_available(struct eventpoll *ep)
+{
+ return ep_polled_by_user(ep) &&
+ ep->user_header->head != ep->user_header->tail;
+}
+
/**
* ep_events_available - Checks if ready events might be available.
*
Helpers for lengths-from-number and number-from-lengths calculations. Among them: ep_polled_by_user() - returns true if epoll was created with EPOLL_USERPOLL ep_user_ring_events_available() - returns true if there is something in user ring buffer Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- fs/eventpoll.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+)