[XFS] replace dquot flush semaphore with a completion

Use the new completion flush code to implement the dquot 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:31822a

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

1 files changed, 12 insertions, 22 deletions

diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c
index 9de42d031745..32290578c661 100644
--- a/fs/xfs/quota/xfs_dquot.c
+++ b/fs/xfs/quota/xfs_dquot.c
@@ -101,9 +101,16 @@ xfs_qm_dqinit(
         if (brandnewdquot) {
                 dqp->dq_flnext = dqp->dq_flprev = dqp;
                 mutex_init(&dqp->q_qlock);
-                initnsema(&dqp->q_flock, 1, "fdq");
                 sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");
 
+                /*
+                 * Because we want to use a counting completion, complete
+                 * the flush completion once to allow a single access to
+                 * the flush completion without blocking.
+                 */
+                init_completion(&dqp->q_flush);
+                complete(&dqp->q_flush);
+
 #ifdef XFS_DQUOT_TRACE
                 dqp->q_trace = ktrace_alloc(DQUOT_TRACE_SIZE, KM_SLEEP);
                 xfs_dqtrace_entry(dqp, "DQINIT");
@@ -150,7 +157,6 @@ xfs_qm_dqdestroy(
         ASSERT(! XFS_DQ_IS_ON_FREELIST(dqp));
 
         mutex_destroy(&dqp->q_qlock);
-        freesema(&dqp->q_flock);
         sv_destroy(&dqp->q_pinwait);
 
 #ifdef XFS_DQUOT_TRACE
@@ -1211,7 +1217,7 @@ xfs_qm_dqflush(
         int                     error;
 
         ASSERT(XFS_DQ_IS_LOCKED(dqp));
-        ASSERT(XFS_DQ_IS_FLUSH_LOCKED(dqp));
+        ASSERT(!completion_done(&dqp->q_flush));
         xfs_dqtrace_entry(dqp, "DQFLUSH");
 
         /*
@@ -1348,34 +1354,18 @@ xfs_qm_dqflush_done(
         xfs_dqfunlock(dqp);
 }
 
-
-int
-xfs_qm_dqflock_nowait(
-        xfs_dquot_t *dqp)
-{
-        int locked;
-
-        locked = cpsema(&((dqp)->q_flock));
-
-        /* XXX ifdef these out */
-        if (locked)
-                (dqp)->dq_flags |= XFS_DQ_FLOCKED;
-        return (locked);
-}
-
-
 int
 xfs_qm_dqlock_nowait(
         xfs_dquot_t *dqp)
 {
-        return (mutex_trylock(&((dqp)->q_qlock)));
+        return mutex_trylock(&dqp->q_qlock);
 }
 
 void
 xfs_dqlock(
         xfs_dquot_t *dqp)
 {
-        mutex_lock(&(dqp->q_qlock));
+        mutex_lock(&dqp->q_qlock);
 }
 
 void
@@ -1468,7 +1458,7 @@ xfs_qm_dqpurge(
          * if we're turning off quotas. Basically, we need this flush
          * lock, and are willing to block on it.
          */
-        if (! xfs_qm_dqflock_nowait(dqp)) {
+        if (!xfs_dqflock_nowait(dqp)) {
                 /*
                  * Block on the flush lock after nudging dquot buffer,
                  * if it is incore.