annotate poll-related wait keys

__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that __poll_t value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

9 files changed, 19 insertions, 18 deletions

diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
index d18b10ff119e..8cc4b48ff127 100644
--- a/drivers/vfio/virqfd.c
+++ b/drivers/vfio/virqfd.c
@@ -46,7 +46,7 @@ static void virqfd_deactivate(struct virqfd *virqfd)
 static int virqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 {
         struct virqfd *virqfd = container_of(wait, struct virqfd, wait);
-        unsigned long flags = (unsigned long)key;
+        __poll_t flags = key_to_poll(key);
 
         if (flags & POLLIN) {
                 /* An event has been signaled, call function */
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c18e70bd0466..7aad77be0b46 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -170,7 +170,7 @@ static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
 {
         struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
 
-        if (!((unsigned long)key & poll->mask))
+        if (!(key_to_poll(key) & poll->mask))
                 return 0;
 
         vhost_poll_queue(poll);
@@ -211,7 +211,7 @@ int vhost_poll_start(struct vhost_poll *poll, struct file *file)
 
         mask = file->f_op->poll(file, &poll->table);
         if (mask)
-                vhost_poll_wakeup(&poll->wait, 0, 0, (void *)(uintptr_t)mask);
+                vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
         if (mask & POLLERR) {
                 if (poll->wqh)
                         remove_wait_queue(poll->wqh, &poll->wait);
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index afd548ebc328..21e6fee00e8b 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1117,6 +1117,7 @@ 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 +1139,7 @@ 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 +1176,8 @@ 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 +1206,7 @@ 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
diff --git a/fs/select.c b/fs/select.c
index b2bf84be5056..ffc16fd3673e 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -212,7 +212,7 @@ static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key
         struct poll_table_entry *entry;
 
         entry = container_of(wait, struct poll_table_entry, wait);
-        if (key && !((unsigned long)key & entry->key))
+        if (key && !(key_to_poll(key) & entry->key))
                 return 0;
         return __pollwake(wait, mode, sync, key);
 }
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 158715445ffb..55a611486bac 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -206,14 +206,16 @@ void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr);
 /*
  * Wakeup macros to be used to report events to the targets.
  */
+#define poll_to_key(m) ((void *)(__force uintptr_t)(__poll_t)(m))
+#define key_to_poll(m) ((__force __poll_t)(uintptr_t)(void *)(m))
 #define wake_up_poll(x, m)                                                      \
-        __wake_up(x, TASK_NORMAL, 1, (void *) (m))
+        __wake_up(x, TASK_NORMAL, 1, poll_to_key(m))
 #define wake_up_locked_poll(x, m)                                               \
-        __wake_up_locked_key((x), TASK_NORMAL, (void *) (m))
+        __wake_up_locked_key((x), TASK_NORMAL, poll_to_key(m))
 #define wake_up_interruptible_poll(x, m)                                        \
-        __wake_up(x, TASK_INTERRUPTIBLE, 1, (void *) (m))
+        __wake_up(x, TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 #define wake_up_interruptible_sync_poll(x, m)                                   \
-        __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, (void *) (m))
+        __wake_up_sync_key((x), TASK_INTERRUPTIBLE, 1, poll_to_key(m))
 
 #define ___wait_cond_timeout(condition)                                         \
 ({                                                                              \
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 50e6906314f8..006aa27f4fb4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3777,7 +3777,7 @@ static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
         struct mem_cgroup_event *event =
                 container_of(wait, struct mem_cgroup_event, wait);
         struct mem_cgroup *memcg = event->memcg;
-        unsigned long flags = (unsigned long)key;
+        __poll_t flags = key_to_poll(key);
 
         if (flags & POLLHUP) {
                 /*
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 522873ed120b..000da13c01f2 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -72,12 +72,10 @@ static inline int connection_based(struct sock *sk)
 static int receiver_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync,
                                   void *key)
 {
-        unsigned long bits = (unsigned long)key;
-
         /*
          * Avoid a wakeup if event not interesting for us
          */
-        if (bits && !(bits & (POLLIN | POLLERR)))
+        if (key && !(key_to_poll(key) & (POLLIN | POLLERR)))
                 return 0;
         return autoremove_wake_function(wait, mode, sync, key);
 }
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index a9ee634f3c42..72957961ac22 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -367,7 +367,7 @@ static int unix_dgram_peer_wake_relay(wait_queue_entry_t *q, unsigned mode, int
         /* relaying can only happen while the wq still exists */
         u_sleep = sk_sleep(&u->sk);
         if (u_sleep)
-                wake_up_interruptible_poll(u_sleep, key);
+                wake_up_interruptible_poll(u_sleep, key_to_poll(key));
 
         return 0;
 }
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index a1f68ed999d8..a334399fafec 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -188,7 +188,7 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 {
         struct kvm_kernel_irqfd *irqfd =
                 container_of(wait, struct kvm_kernel_irqfd, wait);
-        unsigned long flags = (unsigned long)key;
+        __poll_t flags = key_to_poll(key);
         struct kvm_kernel_irq_routing_entry irq;
         struct kvm *kvm = irqfd->kvm;
         unsigned seq;