xfs: convert log grant ticket queues to list heads
The grant write and reserve queues use a roll-your-own double linked
list, so convert it to a standard list_head structure and convert
all the list traversals to use list_for_each_entry(). We can also
get rid of the XLOG_TIC_IN_Q flag as we can use the list_empty()
check to tell if the ticket is in a list or not.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index cee4ab9..1b82735 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -95,38 +95,6 @@
STATIC int xlog_iclogs_empty(xlog_t *log);
-
-static void
-xlog_ins_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
-{
- if (*qp) {
- tic->t_next = (*qp);
- tic->t_prev = (*qp)->t_prev;
- (*qp)->t_prev->t_next = tic;
- (*qp)->t_prev = tic;
- } else {
- tic->t_prev = tic->t_next = tic;
- *qp = tic;
- }
-
- tic->t_flags |= XLOG_TIC_IN_Q;
-}
-
-static void
-xlog_del_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
-{
- if (tic == tic->t_next) {
- *qp = NULL;
- } else {
- *qp = tic->t_next;
- tic->t_next->t_prev = tic->t_prev;
- tic->t_prev->t_next = tic->t_next;
- }
-
- tic->t_next = tic->t_prev = NULL;
- tic->t_flags &= ~XLOG_TIC_IN_Q;
-}
-
static void
xlog_grant_sub_space(struct log *log, int bytes)
{
@@ -724,7 +692,7 @@
log->l_tail_lsn = tail_lsn;
}
- if ((tic = log->l_write_headq)) {
+ if (!list_empty(&log->l_writeq)) {
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("Recovery problem");
@@ -732,7 +700,7 @@
cycle = log->l_grant_write_cycle;
bytes = log->l_grant_write_bytes;
free_bytes = xlog_space_left(log, cycle, bytes);
- do {
+ list_for_each_entry(tic, &log->l_writeq, t_queue) {
ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
if (free_bytes < tic->t_unit_res && tail_lsn != 1)
@@ -740,10 +708,10 @@
tail_lsn = 0;
free_bytes -= tic->t_unit_res;
sv_signal(&tic->t_wait);
- tic = tic->t_next;
- } while (tic != log->l_write_headq);
+ }
}
- if ((tic = log->l_reserve_headq)) {
+
+ if (!list_empty(&log->l_reserveq)) {
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("Recovery problem");
@@ -751,7 +719,7 @@
cycle = log->l_grant_reserve_cycle;
bytes = log->l_grant_reserve_bytes;
free_bytes = xlog_space_left(log, cycle, bytes);
- do {
+ list_for_each_entry(tic, &log->l_reserveq, t_queue) {
if (tic->t_flags & XLOG_TIC_PERM_RESERV)
need_bytes = tic->t_unit_res*tic->t_cnt;
else
@@ -761,8 +729,7 @@
tail_lsn = 0;
free_bytes -= need_bytes;
sv_signal(&tic->t_wait);
- tic = tic->t_next;
- } while (tic != log->l_reserve_headq);
+ }
}
spin_unlock(&log->l_grant_lock);
} /* xfs_log_move_tail */
@@ -1053,6 +1020,8 @@
log->l_curr_cycle = 1; /* 0 is bad since this is initial value */
log->l_grant_reserve_cycle = 1;
log->l_grant_write_cycle = 1;
+ INIT_LIST_HEAD(&log->l_reserveq);
+ INIT_LIST_HEAD(&log->l_writeq);
error = EFSCORRUPTED;
if (xfs_sb_version_hassector(&mp->m_sb)) {
@@ -2550,8 +2519,8 @@
trace_xfs_log_grant_enter(log, tic);
/* something is already sleeping; insert new transaction at end */
- if (log->l_reserve_headq) {
- xlog_ins_ticketq(&log->l_reserve_headq, tic);
+ if (!list_empty(&log->l_reserveq)) {
+ list_add_tail(&tic->t_queue, &log->l_reserveq);
trace_xfs_log_grant_sleep1(log, tic);
@@ -2583,8 +2552,8 @@
free_bytes = xlog_space_left(log, log->l_grant_reserve_cycle,
log->l_grant_reserve_bytes);
if (free_bytes < need_bytes) {
- if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
- xlog_ins_ticketq(&log->l_reserve_headq, tic);
+ if (list_empty(&tic->t_queue))
+ list_add_tail(&tic->t_queue, &log->l_reserveq);
trace_xfs_log_grant_sleep2(log, tic);
@@ -2602,8 +2571,9 @@
trace_xfs_log_grant_wake2(log, tic);
goto redo;
- } else if (tic->t_flags & XLOG_TIC_IN_Q)
- xlog_del_ticketq(&log->l_reserve_headq, tic);
+ }
+
+ list_del_init(&tic->t_queue);
/* we've got enough space */
xlog_grant_add_space(log, need_bytes);
@@ -2626,9 +2596,7 @@
return 0;
error_return:
- if (tic->t_flags & XLOG_TIC_IN_Q)
- xlog_del_ticketq(&log->l_reserve_headq, tic);
-
+ list_del_init(&tic->t_queue);
trace_xfs_log_grant_error(log, tic);
/*
@@ -2653,7 +2621,6 @@
xlog_ticket_t *tic)
{
int free_bytes, need_bytes;
- xlog_ticket_t *ntic;
#ifdef DEBUG
xfs_lsn_t tail_lsn;
#endif
@@ -2683,22 +2650,23 @@
* this transaction.
*/
need_bytes = tic->t_unit_res;
- if ((ntic = log->l_write_headq)) {
+ if (!list_empty(&log->l_writeq)) {
+ struct xlog_ticket *ntic;
free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
log->l_grant_write_bytes);
- do {
+ list_for_each_entry(ntic, &log->l_writeq, t_queue) {
ASSERT(ntic->t_flags & XLOG_TIC_PERM_RESERV);
if (free_bytes < ntic->t_unit_res)
break;
free_bytes -= ntic->t_unit_res;
sv_signal(&ntic->t_wait);
- ntic = ntic->t_next;
- } while (ntic != log->l_write_headq);
+ }
- if (ntic != log->l_write_headq) {
- if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
- xlog_ins_ticketq(&log->l_write_headq, tic);
+ if (ntic != list_first_entry(&log->l_writeq,
+ struct xlog_ticket, t_queue)) {
+ if (list_empty(&tic->t_queue))
+ list_add_tail(&tic->t_queue, &log->l_writeq);
trace_xfs_log_regrant_write_sleep1(log, tic);
@@ -2727,8 +2695,8 @@
free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
log->l_grant_write_bytes);
if (free_bytes < need_bytes) {
- if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
- xlog_ins_ticketq(&log->l_write_headq, tic);
+ if (list_empty(&tic->t_queue))
+ list_add_tail(&tic->t_queue, &log->l_writeq);
spin_unlock(&log->l_grant_lock);
xlog_grant_push_ail(log->l_mp, need_bytes);
spin_lock(&log->l_grant_lock);
@@ -2745,8 +2713,9 @@
trace_xfs_log_regrant_write_wake2(log, tic);
goto redo;
- } else if (tic->t_flags & XLOG_TIC_IN_Q)
- xlog_del_ticketq(&log->l_write_headq, tic);
+ }
+
+ list_del_init(&tic->t_queue);
/* we've got enough space */
xlog_grant_add_space_write(log, need_bytes);
@@ -2766,9 +2735,7 @@
error_return:
- if (tic->t_flags & XLOG_TIC_IN_Q)
- xlog_del_ticketq(&log->l_reserve_headq, tic);
-
+ list_del_init(&tic->t_queue);
trace_xfs_log_regrant_write_error(log, tic);
/*
@@ -3435,6 +3402,7 @@
}
atomic_set(&tic->t_ref, 1);
+ INIT_LIST_HEAD(&tic->t_queue);
tic->t_unit_res = unit_bytes;
tic->t_curr_res = unit_bytes;
tic->t_cnt = cnt;
@@ -3742,26 +3710,17 @@
spin_unlock(&log->l_icloglock);
/*
- * We don't want anybody waiting for log reservations
- * after this. That means we have to wake up everybody
- * queued up on reserve_headq as well as write_headq.
- * In addition, we make sure in xlog_{re}grant_log_space
- * that we don't enqueue anything once the SHUTDOWN flag
- * is set, and this action is protected by the GRANTLOCK.
+ * We don't want anybody waiting for log reservations after this. That
+ * means we have to wake up everybody queued up on reserveq as well as
+ * writeq. In addition, we make sure in xlog_{re}grant_log_space that
+ * we don't enqueue anything once the SHUTDOWN flag is set, and this
+ * action is protected by the GRANTLOCK.
*/
- if ((tic = log->l_reserve_headq)) {
- do {
- sv_signal(&tic->t_wait);
- tic = tic->t_next;
- } while (tic != log->l_reserve_headq);
- }
+ list_for_each_entry(tic, &log->l_reserveq, t_queue)
+ sv_signal(&tic->t_wait);
- if ((tic = log->l_write_headq)) {
- do {
- sv_signal(&tic->t_wait);
- tic = tic->t_next;
- } while (tic != log->l_write_headq);
- }
+ list_for_each_entry(tic, &log->l_writeq, t_queue)
+ sv_signal(&tic->t_wait);
spin_unlock(&log->l_grant_lock);
if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {