[XFS] replace inode flush semaphore with a completion

Use the new completion flush code to implement the inode flush lock.
Removes one of the final users of semaphores in the XFS code base.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31817a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 21 insertions, 4 deletions

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 571724404355..f771df6bfa6f 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -223,7 +223,7 @@ typedef struct xfs_inode {
         struct xfs_inode_log_item *i_itemp;     /* logging information */
         mrlock_t                i_lock;         /* inode lock */
         mrlock_t                i_iolock;       /* inode IO lock */
-        sema_t                  i_flock;        /* inode flush lock */
+        struct completion       i_flush;        /* inode flush completion q */
         atomic_t                i_pincount;     /* inode pin count */
         wait_queue_head_t       i_ipin_wait;    /* inode pinning wait queue */
         spinlock_t              i_flags_lock;   /* inode i_flags lock */
@@ -482,11 +482,8 @@ int		xfs_ilock_nowait(xfs_inode_t *, uint);
 void            xfs_iunlock(xfs_inode_t *, uint);
 void            xfs_ilock_demote(xfs_inode_t *, uint);
 int             xfs_isilocked(xfs_inode_t *, uint);
-void            xfs_iflock(xfs_inode_t *);
-int             xfs_iflock_nowait(xfs_inode_t *);
 uint            xfs_ilock_map_shared(xfs_inode_t *);
 void            xfs_iunlock_map_shared(xfs_inode_t *, uint);
-void            xfs_ifunlock(xfs_inode_t *);
 void            xfs_ireclaim(xfs_inode_t *);
 int             xfs_finish_reclaim(xfs_inode_t *, int, int);
 int             xfs_finish_reclaim_all(struct xfs_mount *, int);
@@ -580,6 +577,26 @@ extern struct kmem_zone	*xfs_ifork_zone;
 extern struct kmem_zone *xfs_inode_zone;
 extern struct kmem_zone *xfs_ili_zone;
 
+/*
+ * Manage the i_flush queue embedded in the inode.  This completion
+ * queue synchronizes processes attempting to flush the in-core
+ * inode back to disk.
+ */
+static inline void xfs_iflock(xfs_inode_t *ip)
+{
+        wait_for_completion(&ip->i_flush);
+}
+
+static inline int xfs_iflock_nowait(xfs_inode_t *ip)
+{
+        return try_wait_for_completion(&ip->i_flush);
+}
+
+static inline void xfs_ifunlock(xfs_inode_t *ip)
+{
+        complete(&ip->i_flush);
+}
+
 #endif  /* __KERNEL__ */
 
 #endif  /* __XFS_INODE_H__ */