Merge branch 'work.poll2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull more poll annotation updates from Al Viro:
 "This is preparation to solving the problems you've mentioned in the
  original poll series.

  After this series, the kernel is ready for running

      for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
            L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
            for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
      done

  as a for bulk search-and-replace.

  After that, the kernel is ready to apply the patch to unify
  {de,}mangle_poll(), and then get rid of kernel-side POLL... uses
  entirely, and we should be all done with that stuff.

  Basically, that's what you suggested wrt KPOLL..., except that we can
  use EPOLL... instead - they already are arch-independent (and equal to
  what is currently kernel-side POLL...).

  After the preparations (in this series) switch to returning EPOLL...
  from ->poll() instances is completely mechanical and kernel-side
  POLL... can go away. The last step (killing kernel-side POLL... and
  unifying {de,}mangle_poll() has to be done after the
  search-and-replace job, since we need userland-side POLL... for
  unified {de,}mangle_poll(), thus the cherry-pick at the last step.

  After that we will have:

   - POLL{IN,OUT,...} *not* in __poll_t, so any stray instances of
     ->poll() still using those will be caught by sparse.

   - eventpoll.c and select.c warning-free wrt __poll_t

   - no more kernel-side definitions of POLL... - userland ones are
     visible through the entire kernel (and used pretty much only for
     mangle/demangle)

   - same behavior as after the first series (i.e. sparc et.al. epoll(2)
     working correctly)"

* 'work.poll2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  annotate ep_scan_ready_list()
  ep_send_events_proc(): return result via esed->res
  preparation to switching ->poll() to returning EPOLL...
  add EPOLLNVAL, annotate EPOLL... and event_poll->event
  use linux/poll.h instead of asm/poll.h
  xen: fix poll misannotation
  smc: missing poll annotations

1 files changed, 23 insertions, 18 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 42e35a6977c9..d1a490c7e6c3 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -260,6 +260,7 @@ struct ep_pqueue {
 struct ep_send_events_data {
         int maxevents;
         struct epoll_event __user *events;
+        int res;
 };
 
 /*
@@ -660,12 +661,13 @@ static inline void ep_pm_stay_awake_rcu(struct epitem *epi)
  *
  * Returns: The same integer error code returned by the @sproc callback.
  */
-static int ep_scan_ready_list(struct eventpoll *ep,
-                              int (*sproc)(struct eventpoll *,
+static __poll_t ep_scan_ready_list(struct eventpoll *ep,
+                              __poll_t (*sproc)(struct eventpoll *,
                                            struct list_head *, void *),
                               void *priv, int depth, bool ep_locked)
 {
-        int error, pwake = 0;
+        __poll_t res;
+        int pwake = 0;
         unsigned long flags;
         struct epitem *epi, *nepi;
         LIST_HEAD(txlist);
@@ -694,7 +696,7 @@ static int ep_scan_ready_list(struct eventpoll *ep,
         /*
          * Now call the callback function.
          */
-        error = (*sproc)(ep, &txlist, priv);
+        res = (*sproc)(ep, &txlist, priv);
 
         spin_lock_irqsave(&ep->lock, flags);
         /*
@@ -747,7 +749,7 @@ static int ep_scan_ready_list(struct eventpoll *ep,
         if (pwake)
                 ep_poll_safewake(&ep->poll_wait);
 
-        return error;
+        return res;
 }
 
 static void epi_rcu_free(struct rcu_head *head)
@@ -864,7 +866,7 @@ static int ep_eventpoll_release(struct inode *inode, struct file *file)
         return 0;
 }
 
-static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
+static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
                                void *priv);
 static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
                                  poll_table *pt);
@@ -874,7 +876,7 @@ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
  * the ep->mtx so we need to start from depth=1, such that mutex_lock_nested()
  * is correctly annotated.
  */
-static unsigned int ep_item_poll(const struct epitem *epi, poll_table *pt,
+static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt,
                                  int depth)
 {
         struct eventpoll *ep;
@@ -894,7 +896,7 @@ static unsigned int ep_item_poll(const struct epitem *epi, poll_table *pt,
                                   locked) & epi->event.events;
 }
 
-static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
+static __poll_t ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
                                void *priv)
 {
         struct epitem *epi, *tmp;
@@ -1414,7 +1416,8 @@ static noinline void ep_destroy_wakeup_source(struct epitem *epi)
 static int ep_insert(struct eventpoll *ep, const struct epoll_event *event,
                      struct file *tfile, int fd, int full_check)
 {
-        int error, revents, pwake = 0;
+        int error, pwake = 0;
+        __poll_t revents;
         unsigned long flags;
         long user_watches;
         struct epitem *epi;
@@ -1612,12 +1615,11 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi,
         return 0;
 }
 
-static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
+static __poll_t ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
                                void *priv)
 {
         struct ep_send_events_data *esed = priv;
-        int eventcnt;
-        unsigned int revents;
+        __poll_t revents;
         struct epitem *epi;
         struct epoll_event __user *uevent;
         struct wakeup_source *ws;
@@ -1630,8 +1632,8 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
          * Items cannot vanish during the loop because ep_scan_ready_list() is
          * holding "mtx" during this call.
          */
-        for (eventcnt = 0, uevent = esed->events;
-             !list_empty(head) && eventcnt < esed->maxevents;) {
+        for (esed->res = 0, uevent = esed->events;
+             !list_empty(head) && esed->res < esed->maxevents;) {
                 epi = list_first_entry(head, struct epitem, rdllink);
 
                 /*
@@ -1665,9 +1667,11 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
                             __put_user(epi->event.data, &uevent->data)) {
                                 list_add(&epi->rdllink, head);
                                 ep_pm_stay_awake(epi);
-                                return eventcnt ? eventcnt : -EFAULT;
+                                if (!esed->res)
+                                        esed->res = -EFAULT;
+                                return 0;
                         }
-                        eventcnt++;
+                        esed->res++;
                         uevent++;
                         if (epi->event.events & EPOLLONESHOT)
                                 epi->event.events &= EP_PRIVATE_BITS;
@@ -1689,7 +1693,7 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
                 }
         }
 
-        return eventcnt;
+        return 0;
 }
 
 static int ep_send_events(struct eventpoll *ep,
@@ -1700,7 +1704,8 @@ static int ep_send_events(struct eventpoll *ep,
         esed.maxevents = maxevents;
         esed.events = events;
 
-        return ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false);
+        ep_scan_ready_list(ep, ep_send_events_proc, &esed, 0, false);
+        return esed.res;
 }
 
 static inline struct timespec64 ep_set_mstimeout(long ms)