Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull poll annotations from Al Viro:
 "This introduces a __bitwise type for POLL### bitmap, and propagates
  the annotations through the tree. Most of that stuff is as simple as
  'make ->poll() instances return __poll_t and do the same to local
  variables used to hold the future return value'.

  Some of the obvious brainos found in process are fixed (e.g. POLLIN
  misspelled as POLL_IN). At that point the amount of sparse warnings is
  low and most of them are for genuine bugs - e.g. ->poll() instance
  deciding to return -EINVAL instead of a bitmap. I hadn't touched those
  in this series - it's large enough as it is.

  Another problem it has caught was eventpoll() ABI mess; select.c and
  eventpoll.c assumed that corresponding POLL### and EPOLL### were
  equal. That's true for some, but not all of them - EPOLL### are
  arch-independent, but POLL### are not.

  The last commit in this series separates userland POLL### values from
  the (now arch-independent) kernel-side ones, converting between them
  in the few places where they are copied to/from userland. AFAICS, this
  is the least disruptive fix preserving poll(2) ABI and making epoll()
  work on all architectures.

  As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
  it will trigger only on what would've triggered EPOLLWRBAND on other
  architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
  at all on sparc. With this patch they should work consistently on all
  architectures"

* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
  make kernel-side POLL... arch-independent
  eventpoll: no need to mask the result of epi_item_poll() again
  eventpoll: constify struct epoll_event pointers
  debugging printk in sg_poll() uses %x to print POLL... bitmap
  annotate poll(2) guts
  9p: untangle ->poll() mess
  ->si_band gets POLL... bitmap stored into a user-visible long field
  ring_buffer_poll_wait() return value used as return value of ->poll()
  the rest of drivers/*: annotate ->poll() instances
  media: annotate ->poll() instances
  fs: annotate ->poll() instances
  ipc, kernel, mm: annotate ->poll() instances
  net: annotate ->poll() instances
  apparmor: annotate ->poll() instances
  tomoyo: annotate ->poll() instances
  sound: annotate ->poll() instances
  acpi: annotate ->poll() instances
  crypto: annotate ->poll() instances
  block: annotate ->poll() instances
  x86: annotate ->poll() instances
  ...

1 files changed, 13 insertions, 15 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index afd548ebc3282..42e35a6977c9e 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -874,7 +874,8 @@ 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(struct epitem *epi, poll_table *pt, int depth)
+static unsigned int ep_item_poll(const struct epitem *epi, poll_table *pt,
+				 int depth)
 {
 	struct eventpoll *ep;
 	bool locked;
@@ -920,7 +921,7 @@ static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head,
 	return 0;
 }
 
-static unsigned int ep_eventpoll_poll(struct file *file, poll_table *wait)
+static __poll_t ep_eventpoll_poll(struct file *file, poll_table *wait)
 {
 	struct eventpoll *ep = file->private_data;
 	int depth = 0;
@@ -1117,6 +1118,7 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v
 	unsigned long flags;
 	struct epitem *epi = ep_item_from_wait(wait);
 	struct eventpoll *ep = epi->ep;
+	__poll_t pollflags = key_to_poll(key);
 	int ewake = 0;
 
 	spin_lock_irqsave(&ep->lock, flags);
@@ -1138,7 +1140,7 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v
 	 * callback. We need to be able to handle both cases here, hence the
 	 * test for "key" != NULL before the event match test.
 	 */
-	if (key && !((unsigned long) key & epi->event.events))
+	if (pollflags && !(pollflags & epi->event.events))
 		goto out_unlock;
 
 	/*
@@ -1175,8 +1177,8 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v
 	 */
 	if (waitqueue_active(&ep->wq)) {
 		if ((epi->event.events & EPOLLEXCLUSIVE) &&
-					!((unsigned long)key & POLLFREE)) {
-			switch ((unsigned long)key & EPOLLINOUT_BITS) {
+					!(pollflags & POLLFREE)) {
+			switch (pollflags & EPOLLINOUT_BITS) {
 			case POLLIN:
 				if (epi->event.events & POLLIN)
 					ewake = 1;
@@ -1205,7 +1207,7 @@ out_unlock:
 	if (!(epi->event.events & EPOLLEXCLUSIVE))
 		ewake = 1;
 
-	if ((unsigned long)key & POLLFREE) {
+	if (pollflags & POLLFREE) {
 		/*
 		 * If we race with ep_remove_wait_queue() it can miss
 		 * ->whead = NULL and do another remove_wait_queue() after
@@ -1409,7 +1411,7 @@ static noinline void ep_destroy_wakeup_source(struct epitem *epi)
 /*
  * Must be called with "mtx" held.
  */
-static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
+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;
@@ -1486,7 +1488,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
 	ep_set_busy_poll_napi_id(epi);
 
 	/* If the file is already "ready" we drop it inside the ready list */
-	if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) {
+	if (revents && !ep_is_linked(&epi->rdllink)) {
 		list_add_tail(&epi->rdllink, &ep->rdllist);
 		ep_pm_stay_awake(epi);
 
@@ -1540,10 +1542,10 @@ error_create_wakeup_source:
  * Modify the interest event mask by dropping an event if the new mask
  * has a match in the current file status. Must be called with "mtx" held.
  */
-static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_event *event)
+static int ep_modify(struct eventpoll *ep, struct epitem *epi,
+		     const struct epoll_event *event)
 {
 	int pwake = 0;
-	unsigned int revents;
 	poll_table pt;
 
 	init_poll_funcptr(&pt, NULL);
@@ -1585,14 +1587,10 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even
 	/*
 	 * Get current event bits. We can safely use the file* here because
 	 * its usage count has been increased by the caller of this function.
-	 */
-	revents = ep_item_poll(epi, &pt, 1);
-
-	/*
 	 * If the item is "hot" and it is not registered inside the ready
 	 * list, push it inside.
 	 */
-	if (revents & event->events) {
+	if (ep_item_poll(epi, &pt, 1)) {
 		spin_lock_irq(&ep->lock);
 		if (!ep_is_linked(&epi->rdllink)) {
 			list_add_tail(&epi->rdllink, &ep->rdllist);