xfs: remove log space waitqueues

The tic->t_wait waitqueues can never have more than a single waiter
on them, so we can easily replace them with a task_struct pointer
and wake_up_process.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

2 files changed, 16 insertions, 10 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 2db39df5a57d..02a35fba5eae 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -169,7 +169,7 @@ xlog_reserveq_wake(
                 *free_bytes -= need_bytes;
 
                 trace_xfs_log_grant_wake_up(log, tic);
-                wake_up(&tic->t_wait);
+                wake_up_process(tic->t_task);
         }
 
         return true;
@@ -193,7 +193,7 @@ xlog_writeq_wake(
                 *free_bytes -= need_bytes;
 
                 trace_xfs_log_regrant_write_wake_up(log, tic);
-                wake_up(&tic->t_wait);
+                wake_up_process(tic->t_task);
         }
 
         return true;
@@ -212,10 +212,13 @@ xlog_reserveq_wait(
                         goto shutdown;
                 xlog_grant_push_ail(log, need_bytes);
 
+                __set_current_state(TASK_UNINTERRUPTIBLE);
+                spin_unlock(&log->l_grant_reserve_lock);
+
                 XFS_STATS_INC(xs_sleep_logspace);
-                trace_xfs_log_grant_sleep(log, tic);
 
-                xlog_wait(&tic->t_wait, &log->l_grant_reserve_lock);
+                trace_xfs_log_grant_sleep(log, tic);
+                schedule();
                 trace_xfs_log_grant_wake(log, tic);
 
                 spin_lock(&log->l_grant_reserve_lock);
@@ -243,10 +246,13 @@ xlog_writeq_wait(
                         goto shutdown;
                 xlog_grant_push_ail(log, need_bytes);
 
+                __set_current_state(TASK_UNINTERRUPTIBLE);
+                spin_unlock(&log->l_grant_write_lock);
+
                 XFS_STATS_INC(xs_sleep_logspace);
-                trace_xfs_log_regrant_write_sleep(log, tic);
 
-                xlog_wait(&tic->t_wait, &log->l_grant_write_lock);
+                trace_xfs_log_regrant_write_sleep(log, tic);
+                schedule();
                 trace_xfs_log_regrant_write_wake(log, tic);
 
                 spin_lock(&log->l_grant_write_lock);
@@ -3276,6 +3282,7 @@ xlog_ticket_alloc(
         }
 
         atomic_set(&tic->t_ref, 1);
+        tic->t_task             = current;
         INIT_LIST_HEAD(&tic->t_queue);
         tic->t_unit_res         = unit_bytes;
         tic->t_curr_res         = unit_bytes;
@@ -3287,7 +3294,6 @@ xlog_ticket_alloc(
         tic->t_trans_type       = 0;
         if (xflags & XFS_LOG_PERM_RESERV)
                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
-        init_waitqueue_head(&tic->t_wait);
 
         xlog_tic_reset_res(tic);
 
@@ -3615,12 +3621,12 @@ xfs_log_force_umount(
          */
         spin_lock(&log->l_grant_reserve_lock);
         list_for_each_entry(tic, &log->l_reserveq, t_queue)
-                wake_up(&tic->t_wait);
+                wake_up_process(tic->t_task);
         spin_unlock(&log->l_grant_reserve_lock);
 
         spin_lock(&log->l_grant_write_lock);
         list_for_each_entry(tic, &log->l_writeq, t_queue)
-                wake_up(&tic->t_wait);
+                wake_up_process(tic->t_task);
         spin_unlock(&log->l_grant_write_lock);
 
         if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 785905e3cf03..d8c5e47bbc2f 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -239,8 +239,8 @@ typedef struct xlog_res {
 } xlog_res_t;
 
 typedef struct xlog_ticket {
-        wait_queue_head_t  t_wait;       /* ticket wait queue */
         struct list_head   t_queue;      /* reserve/write queue */
+        struct task_struct *t_task;      /* task that owns this ticket */
         xlog_tid_t         t_tid;        /* transaction identifier       : 4  */
         atomic_t           t_ref;        /* ticket reference count       : 4  */
         int                t_curr_res;   /* current reservation in bytes : 4  */