Merge branch 'akpm' (Andrew's patch-bomb)

Merge misc patches from Andrew Morton:
 "The MM tree is rather stuck while I wait to find out what the heck is
  happening with sched/numa.  Probably I'll need to route around all the
  code which was added to -next, sigh.

  So this is "everything else", or at least most of it - other small
  bits are still awaiting resolutions of various kinds."

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits)
  lib/decompress.c add __init to decompress_method and data
  kernel/resource.c: fix stack overflow in __reserve_region_with_split()
  omfs: convert to use beXX_add_cpu()
  taskstats: cgroupstats_user_cmd() may leak on error
  aoe: update aoe-internal version number to 50
  aoe: update documentation to better reflect aoe-plus-udev usage
  aoe: remove unused code
  aoe: make dynamic block minor numbers the default
  aoe: update and specify AoE address guards and error messages
  aoe: retain static block device numbers for backwards compatibility
  aoe: support more AoE addresses with dynamic block device minor numbers
  aoe: update documentation with new URL and VM settings reference
  aoe: update copyright year in touched files
  aoe: update internal version number to 49
  aoe: remove unused code and add cosmetic improvements
  aoe: increase net_device reference count while using it
  aoe: associate frames with the AoE storage target
  aoe: disallow unsupported AoE minor addresses
  aoe: do revalidation steps in order
  aoe: failover remote interface based on aoe_deadsecs parameter
  ...

1 files changed, 35 insertions, 3 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index cd96649bfe6..da72250ddc1 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -346,7 +346,7 @@ static inline struct epitem *ep_item_from_epqueue(poll_table *p)
 /* Tells if the epoll_ctl(2) operation needs an event copy from userspace */
 static inline int ep_op_has_event(int op)
 {
-	return op != EPOLL_CTL_DEL;
+	return op == EPOLL_CTL_ADD || op == EPOLL_CTL_MOD;
 }
 
 /* Initialize the poll safe wake up structure */
@@ -676,6 +676,34 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi)
 	return 0;
 }
 
+/*
+ * Disables a "struct epitem" in the eventpoll set. Returns -EBUSY if the item
+ * had no event flags set, indicating that another thread may be currently
+ * handling that item's events (in the case that EPOLLONESHOT was being
+ * used). Otherwise a zero result indicates that the item has been disabled
+ * from receiving events. A disabled item may be re-enabled via
+ * EPOLL_CTL_MOD. Must be called with "mtx" held.
+ */
+static int ep_disable(struct eventpoll *ep, struct epitem *epi)
+{
+	int result = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ep->lock, flags);
+	if (epi->event.events & ~EP_PRIVATE_BITS) {
+		if (ep_is_linked(&epi->rdllink))
+			list_del_init(&epi->rdllink);
+		/* Ensure ep_poll_callback will not add epi back onto ready
+		   list: */
+		epi->event.events &= EP_PRIVATE_BITS;
+		}
+	else
+		result = -EBUSY;
+	spin_unlock_irqrestore(&ep->lock, flags);
+
+	return result;
+}
+
 static void ep_free(struct eventpoll *ep)
 {
 	struct rb_node *rbp;
@@ -1020,8 +1048,6 @@ static void ep_rbtree_insert(struct eventpoll *ep, struct epitem *epi)
 	rb_insert_color(&epi->rbn, &ep->rbr);
 }
 
-
-
 #define PATH_ARR_SIZE 5
 /*
  * These are the number paths of length 1 to 5, that we are allowing to emanate
@@ -1787,6 +1813,12 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
 		} else
 			error = -ENOENT;
 		break;
+	case EPOLL_CTL_DISABLE:
+		if (epi)
+			error = ep_disable(ep, epi);
+		else
+			error = -ENOENT;
+		break;
 	}
 	mutex_unlock(&ep->mtx);