3 files changed, 39 insertions, 42 deletions

diff --git a/fs/xfs/linux-2.6/xfs_vnode.c b/fs/xfs/linux-2.6/xfs_vnode.c
index 5cad3274db02..b52528bbbfff 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.c
+++ b/fs/xfs/linux-2.6/xfs_vnode.c
@@ -33,7 +33,7 @@
 
 
 /*
- * Dedicated vnode inactive/reclaim sync semaphores.
+ * Dedicated vnode inactive/reclaim sync wait queues.
  * Prime number of hash buckets since address is used as the key.
  */
 #define NVSYNC                  37
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 91b00a5686cd..0816c5d6d76b 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -357,11 +357,11 @@ xfs_log_done(xfs_mount_t	*mp,
  * Asynchronous forces are implemented by setting the WANT_SYNC
  * bit in the appropriate in-core log and then returning.
  *
- * Synchronous forces are implemented with a semaphore.  All callers
- * to force a given lsn to disk will wait on a semaphore attached to the
+ * Synchronous forces are implemented with a signal variable. All callers
+ * to force a given lsn to disk will wait on a the sv attached to the
  * specific in-core log.  When given in-core log finally completes its
  * write to disk, that thread will wake up all threads waiting on the
- * semaphore.
+ * sv.
  */
 int
 _xfs_log_force(
@@ -707,7 +707,7 @@ xfs_log_unmount_write(xfs_mount_t *mp)
                 if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
                       iclog->ic_state == XLOG_STATE_DIRTY)) {
                         if (!XLOG_FORCED_SHUTDOWN(log)) {
-                                sv_wait(&iclog->ic_forcesema, PMEM,
+                                sv_wait(&iclog->ic_force_wait, PMEM,
                                         &log->l_icloglock, s);
                         } else {
                                 spin_unlock(&log->l_icloglock);
@@ -748,7 +748,7 @@ xfs_log_unmount_write(xfs_mount_t *mp)
                         || iclog->ic_state == XLOG_STATE_DIRTY
                         || iclog->ic_state == XLOG_STATE_IOERROR) ) {
 
-                                sv_wait(&iclog->ic_forcesema, PMEM,
+                                sv_wait(&iclog->ic_force_wait, PMEM,
                                         &log->l_icloglock, s);
                 } else {
                         spin_unlock(&log->l_icloglock);
@@ -838,7 +838,7 @@ xfs_log_move_tail(xfs_mount_t	*mp,
                                 break;
                         tail_lsn = 0;
                         free_bytes -= tic->t_unit_res;
-                        sv_signal(&tic->t_sema);
+                        sv_signal(&tic->t_wait);
                         tic = tic->t_next;
                 } while (tic != log->l_write_headq);
         }
@@ -859,7 +859,7 @@ xfs_log_move_tail(xfs_mount_t	*mp,
                                 break;
                         tail_lsn = 0;
                         free_bytes -= need_bytes;
-                        sv_signal(&tic->t_sema);
+                        sv_signal(&tic->t_wait);
                         tic = tic->t_next;
                 } while (tic != log->l_reserve_headq);
         }
@@ -1285,8 +1285,8 @@ xlog_alloc_log(xfs_mount_t	*mp,
 
                 ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
                 ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
-                sv_init(&iclog->ic_forcesema, SV_DEFAULT, "iclog-force");
-                sv_init(&iclog->ic_writesema, SV_DEFAULT, "iclog-write");
+                sv_init(&iclog->ic_force_wait, SV_DEFAULT, "iclog-force");
+                sv_init(&iclog->ic_write_wait, SV_DEFAULT, "iclog-write");
 
                 iclogp = &iclog->ic_next;
         }
@@ -1565,8 +1565,8 @@ xlog_dealloc_log(xlog_t *log)
 
         iclog = log->l_iclog;
         for (i=0; i<log->l_iclog_bufs; i++) {
-                sv_destroy(&iclog->ic_forcesema);
-                sv_destroy(&iclog->ic_writesema);
+                sv_destroy(&iclog->ic_force_wait);
+                sv_destroy(&iclog->ic_write_wait);
                 xfs_buf_free(iclog->ic_bp);
 #ifdef XFS_LOG_TRACE
                 if (iclog->ic_trace != NULL) {
@@ -1976,7 +1976,7 @@ xlog_write(xfs_mount_t *	mp,
 /* Clean iclogs starting from the head.  This ordering must be
  * maintained, so an iclog doesn't become ACTIVE beyond one that
  * is SYNCING.  This is also required to maintain the notion that we use
- * a counting semaphore to hold off would be writers to the log when every
+ * a ordered wait queue to hold off would be writers to the log when every
  * iclog is trying to sync to disk.
  *
  * State Change: DIRTY -> ACTIVE
@@ -2240,7 +2240,7 @@ xlog_state_do_callback(
                         xlog_state_clean_log(log);
 
                         /* wake up threads waiting in xfs_log_force() */
-                        sv_broadcast(&iclog->ic_forcesema);
+                        sv_broadcast(&iclog->ic_force_wait);
 
                         iclog = iclog->ic_next;
                 } while (first_iclog != iclog);
@@ -2302,8 +2302,7 @@ xlog_state_do_callback(
  * the second completion goes through.
  *
  * Callbacks could take time, so they are done outside the scope of the
- * global state machine log lock.  Assume that the calls to cvsema won't
- * take a long time.  At least we know it won't sleep.
+ * global state machine log lock.
  */
 STATIC void
 xlog_state_done_syncing(
@@ -2339,7 +2338,7 @@ xlog_state_done_syncing(
          * iclog buffer, we wake them all, one will get to do the
          * I/O, the others get to wait for the result.
          */
-        sv_broadcast(&iclog->ic_writesema);
+        sv_broadcast(&iclog->ic_write_wait);
         spin_unlock(&log->l_icloglock);
         xlog_state_do_callback(log, aborted, iclog);    /* also cleans log */
 }       /* xlog_state_done_syncing */
@@ -2347,11 +2346,9 @@ xlog_state_done_syncing(
 
 /*
  * If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
- * sleep.  The flush semaphore is set to the number of in-core buffers and
- * decremented around disk syncing.  Therefore, if all buffers are syncing,
- * this semaphore will cause new writes to sleep until a sync completes.
- * Otherwise, this code just does p() followed by v().  This approximates
- * a sleep/wakeup except we can't race.
+ * sleep.  We wait on the flush queue on the head iclog as that should be
+ * the first iclog to complete flushing. Hence if all iclogs are syncing,
+ * we will wait here and all new writes will sleep until a sync completes.
  *
  * The in-core logs are used in a circular fashion. They are not used
  * out-of-order even when an iclog past the head is free.
@@ -2508,7 +2505,7 @@ xlog_grant_log_space(xlog_t	   *log,
                         goto error_return;
 
                 XFS_STATS_INC(xs_sleep_logspace);
-                sv_wait(&tic->t_sema, PINOD|PLTWAIT, &log->l_grant_lock, s);
+                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
                 /*
                  * If we got an error, and the filesystem is shutting down,
                  * we'll catch it down below. So just continue...
@@ -2534,7 +2531,7 @@ redo:
                 xlog_trace_loggrant(log, tic,
                                     "xlog_grant_log_space: sleep 2");
                 XFS_STATS_INC(xs_sleep_logspace);
-                sv_wait(&tic->t_sema, PINOD|PLTWAIT, &log->l_grant_lock, s);
+                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
 
                 if (XLOG_FORCED_SHUTDOWN(log)) {
                         spin_lock(&log->l_grant_lock);
@@ -2633,7 +2630,7 @@ xlog_regrant_write_log_space(xlog_t	   *log,
                         if (free_bytes < ntic->t_unit_res)
                                 break;
                         free_bytes -= ntic->t_unit_res;
-                        sv_signal(&ntic->t_sema);
+                        sv_signal(&ntic->t_wait);
                         ntic = ntic->t_next;
                 } while (ntic != log->l_write_headq);
 
@@ -2644,7 +2641,7 @@ xlog_regrant_write_log_space(xlog_t	   *log,
                         xlog_trace_loggrant(log, tic,
                                     "xlog_regrant_write_log_space: sleep 1");
                         XFS_STATS_INC(xs_sleep_logspace);
-                        sv_wait(&tic->t_sema, PINOD|PLTWAIT,
+                        sv_wait(&tic->t_wait, PINOD|PLTWAIT,
                                 &log->l_grant_lock, s);
 
                         /* If we're shutting down, this tic is already
@@ -2673,7 +2670,7 @@ redo:
                 if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
                         xlog_ins_ticketq(&log->l_write_headq, tic);
                 XFS_STATS_INC(xs_sleep_logspace);
-                sv_wait(&tic->t_sema, PINOD|PLTWAIT, &log->l_grant_lock, s);
+                sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
 
                 /* If we're shutting down, this tic is already off the queue */
                 if (XLOG_FORCED_SHUTDOWN(log)) {
@@ -2916,7 +2913,7 @@ xlog_state_switch_iclogs(xlog_t		*log,
  *      2. the current iclog is drity, and the previous iclog is in the
  *              active or dirty state.
  *
- * We may sleep (call psema) if:
+ * We may sleep if:
  *
  *      1. the current iclog is not in the active nor dirty state.
  *      2. the current iclog dirty, and the previous iclog is not in the
@@ -3013,7 +3010,7 @@ maybe_sleep:
                         return XFS_ERROR(EIO);
                 }
                 XFS_STATS_INC(xs_log_force_sleep);
-                sv_wait(&iclog->ic_forcesema, PINOD, &log->l_icloglock, s);
+                sv_wait(&iclog->ic_force_wait, PINOD, &log->l_icloglock, s);
                 /*
                  * No need to grab the log lock here since we're
                  * only deciding whether or not to return EIO
@@ -3096,7 +3093,7 @@ try_again:
                                                  XLOG_STATE_SYNCING))) {
                         ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
                         XFS_STATS_INC(xs_log_force_sleep);
-                        sv_wait(&iclog->ic_prev->ic_writesema, PSWP,
+                        sv_wait(&iclog->ic_prev->ic_write_wait, PSWP,
                                 &log->l_icloglock, s);
                         *log_flushed = 1;
                         already_slept = 1;
@@ -3116,7 +3113,7 @@ try_again:
             !(iclog->ic_state & (XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))) {
 
                 /*
-                 * Don't wait on the forcesema if we know that we've
+                 * Don't wait on completion if we know that we've
                  * gotten a log write error.
                  */
                 if (iclog->ic_state & XLOG_STATE_IOERROR) {
@@ -3124,7 +3121,7 @@ try_again:
                         return XFS_ERROR(EIO);
                 }
                 XFS_STATS_INC(xs_log_force_sleep);
-                sv_wait(&iclog->ic_forcesema, PSWP, &log->l_icloglock, s);
+                sv_wait(&iclog->ic_force_wait, PSWP, &log->l_icloglock, s);
                 /*
                  * No need to grab the log lock here since we're
                  * only deciding whether or not to return EIO
@@ -3180,7 +3177,7 @@ STATIC void
 xlog_ticket_put(xlog_t          *log,
                 xlog_ticket_t   *ticket)
 {
-        sv_destroy(&ticket->t_sema);
+        sv_destroy(&ticket->t_wait);
         kmem_zone_free(xfs_log_ticket_zone, ticket);
 }       /* xlog_ticket_put */
 
@@ -3270,7 +3267,7 @@ xlog_ticket_get(xlog_t		*log,
         tic->t_trans_type       = 0;
         if (xflags & XFS_LOG_PERM_RESERV)
                 tic->t_flags |= XLOG_TIC_PERM_RESERV;
-        sv_init(&(tic->t_sema), SV_DEFAULT, "logtick");
+        sv_init(&(tic->t_wait), SV_DEFAULT, "logtick");
 
         xlog_tic_reset_res(tic);
 
@@ -3557,14 +3554,14 @@ xfs_log_force_umount(
          */
         if ((tic = log->l_reserve_headq)) {
                 do {
-                        sv_signal(&tic->t_sema);
+                        sv_signal(&tic->t_wait);
                         tic = tic->t_next;
                 } while (tic != log->l_reserve_headq);
         }
 
         if ((tic = log->l_write_headq)) {
                 do {
-                        sv_signal(&tic->t_sema);
+                        sv_signal(&tic->t_wait);
                         tic = tic->t_next;
                 } while (tic != log->l_write_headq);
         }
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 6245913196b4..7dcf11e0b2f0 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -241,7 +241,7 @@ typedef struct xlog_res {
 } xlog_res_t;
 
 typedef struct xlog_ticket {
-        sv_t               t_sema;       /* sleep on this semaphore      : 20 */
+        sv_t               t_wait;       /* ticket wait queue            : 20 */
         struct xlog_ticket *t_next;      /*                              :4|8 */
         struct xlog_ticket *t_prev;      /*                              :4|8 */
         xlog_tid_t         t_tid;        /* transaction identifier       : 4  */
@@ -314,7 +314,7 @@ typedef struct xlog_rec_ext_header {
  *      xlog_rec_header_t into the reserved space.
  * - ic_data follows, so a write to disk can start at the beginning of
  *      the iclog.
- * - ic_forcesema is used to implement synchronous forcing of the iclog to disk.
+ * - ic_forcewait is used to implement synchronous forcing of the iclog to disk.
  * - ic_next is the pointer to the next iclog in the ring.
  * - ic_bp is a pointer to the buffer used to write this incore log to disk.
  * - ic_log is a pointer back to the global log structure.
@@ -339,8 +339,8 @@ typedef struct xlog_rec_ext_header {
  * and move everything else out to subsequent cachelines.
  */
 typedef struct xlog_iclog_fields {
-        sv_t                    ic_forcesema;
-        sv_t                    ic_writesema;
+        sv_t                    ic_force_wait;
+        sv_t                    ic_write_wait;
         struct xlog_in_core     *ic_next;
         struct xlog_in_core     *ic_prev;
         struct xfs_buf          *ic_bp;
@@ -377,8 +377,8 @@ typedef struct xlog_in_core {
 /*
  * Defines to save our code from this glop.
  */
-#define ic_forcesema    hic_fields.ic_forcesema
-#define ic_writesema    hic_fields.ic_writesema
+#define ic_force_wait   hic_fields.ic_force_wait
+#define ic_write_wait   hic_fields.ic_write_wait
 #define ic_next         hic_fields.ic_next
 #define ic_prev         hic_fields.ic_prev
 #define ic_bp           hic_fields.ic_bp