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authorDavid S. Miller <davem@davemloft.net>2014-11-14 01:01:12 -0500
committerDavid S. Miller <davem@davemloft.net>2014-11-14 01:01:12 -0500
commit076ce4482569ea1a2c27b4ca71a309adaf91d398 (patch)
tree2ae9e42612f35be897f190983fc292d7af781cd2 /fs/notify/mark.c
parentd649a7a81f3b5bacb1d60abd7529894d8234a666 (diff)
parentb23dc5a7cc6ebc9a0d57351da7a0e8454c9ffea3 (diff)
downloadlinux-076ce4482569ea1a2c27b4ca71a309adaf91d398.tar.bz2
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/ethernet/chelsio/cxgb4vf/sge.c drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c sge.c was overlapping two changes, one to use the new __dev_alloc_page() in net-next, and one to use s->fl_pg_order in net. ixgbe_phy.c was a set of overlapping whitespace changes. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs/notify/mark.c')
-rw-r--r--fs/notify/mark.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index d90deaa08e78..34c38fabf514 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -210,6 +210,42 @@ void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mas
}
/*
+ * Sorting function for lists of fsnotify marks.
+ *
+ * Fanotify supports different notification classes (reflected as priority of
+ * notification group). Events shall be passed to notification groups in
+ * decreasing priority order. To achieve this marks in notification lists for
+ * inodes and vfsmounts are sorted so that priorities of corresponding groups
+ * are descending.
+ *
+ * Furthermore correct handling of the ignore mask requires processing inode
+ * and vfsmount marks of each group together. Using the group address as
+ * further sort criterion provides a unique sorting order and thus we can
+ * merge inode and vfsmount lists of marks in linear time and find groups
+ * present in both lists.
+ *
+ * A return value of 1 signifies that b has priority over a.
+ * A return value of 0 signifies that the two marks have to be handled together.
+ * A return value of -1 signifies that a has priority over b.
+ */
+int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
+{
+ if (a == b)
+ return 0;
+ if (!a)
+ return 1;
+ if (!b)
+ return -1;
+ if (a->priority < b->priority)
+ return 1;
+ if (a->priority > b->priority)
+ return -1;
+ if (a < b)
+ return 1;
+ return -1;
+}
+
+/*
* Attach an initialized mark to a given group and fs object.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which group.