Currently the lkb_wait_count is locked by the rsb lock and it should be
fine to handle lkb_wait_count as non atomic_t value. However for the
overall process of reducing locking this patch converts it to an
atomic_t value.
Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
---
fs/dlm/dlm_internal.h | 2 +-
fs/dlm/lock.c | 32 ++++++++++++++------------------
2 files changed, 15 insertions(+), 19 deletions(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 986a9d7b1f33..c8156770205e 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -246,7 +246,7 @@ struct dlm_lkb {
int8_t lkb_highbast; /* highest mode bast sent for */
int8_t lkb_wait_type; /* type of reply waiting for */
- int8_t lkb_wait_count;
+ atomic_t lkb_wait_count;
int lkb_wait_nodeid; /* for debugging */
struct list_head lkb_statequeue; /* rsb g/c/w list */
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index ede903246fa4..f511a9d7d416 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1407,6 +1407,7 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype, int to_nodeid)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int error = 0;
+ int wc;
mutex_lock(&ls->ls_waiters_mutex);
@@ -1428,20 +1429,17 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype, int to_nodeid)
error = -EBUSY;
goto out;
}
- lkb->lkb_wait_count++;
+ wc = atomic_inc_return(&lkb->lkb_wait_count);
hold_lkb(lkb);
log_debug(ls, "addwait %x cur %d overlap %d count %d f %x",
- lkb->lkb_id, lkb->lkb_wait_type, mstype,
- lkb->lkb_wait_count, dlm_iflags_val(lkb));
+ lkb->lkb_id, lkb->lkb_wait_type, mstype, wc,
+ dlm_iflags_val(lkb));
goto out;
}
- DLM_ASSERT(!lkb->lkb_wait_count,
- dlm_print_lkb(lkb);
- printk("wait_count %d\n", lkb->lkb_wait_count););
-
- lkb->lkb_wait_count++;
+ wc = atomic_fetch_inc(&lkb->lkb_wait_count);
+ DLM_ASSERT(!wc, dlm_print_lkb(lkb); printk("wait_count %d\n", wc););
lkb->lkb_wait_type = mstype;
lkb->lkb_wait_nodeid = to_nodeid; /* for debugging */
hold_lkb(lkb);
@@ -1504,7 +1502,7 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype,
log_debug(ls, "remwait %x convert_reply zap overlap_cancel",
lkb->lkb_id);
lkb->lkb_wait_type = 0;
- lkb->lkb_wait_count--;
+ atomic_dec(&lkb->lkb_wait_count);
unhold_lkb(lkb);
goto out_del;
}
@@ -1531,16 +1529,15 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype,
if (overlap_done && lkb->lkb_wait_type) {
log_error(ls, "remwait error %x reply %d wait_type %d overlap",
lkb->lkb_id, mstype, lkb->lkb_wait_type);
- lkb->lkb_wait_count--;
+ atomic_dec(&lkb->lkb_wait_count);
unhold_lkb(lkb);
lkb->lkb_wait_type = 0;
}
- DLM_ASSERT(lkb->lkb_wait_count, dlm_print_lkb(lkb););
+ DLM_ASSERT(atomic_read(&lkb->lkb_wait_count), dlm_print_lkb(lkb););
clear_bit(DLM_IFL_RESEND_BIT, &lkb->lkb_iflags);
- lkb->lkb_wait_count--;
- if (!lkb->lkb_wait_count)
+ if (atomic_dec_and_test(&lkb->lkb_wait_count))
list_del_init(&lkb->lkb_wait_reply);
unhold_lkb(lkb);
return 0;
@@ -2669,7 +2666,7 @@ static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
goto out;
/* lock not allowed if there's any op in progress */
- if (lkb->lkb_wait_type || lkb->lkb_wait_count)
+ if (lkb->lkb_wait_type || atomic_read(&lkb->lkb_wait_count))
goto out;
if (is_overlap(lkb))
@@ -2731,7 +2728,7 @@ static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
/* normal unlock not allowed if there's any op in progress */
if (!(args->flags & (DLM_LKF_CANCEL | DLM_LKF_FORCEUNLOCK)) &&
- (lkb->lkb_wait_type || lkb->lkb_wait_count))
+ (lkb->lkb_wait_type || atomic_read(&lkb->lkb_wait_count)))
goto out;
/* an lkb may be waiting for an rsb lookup to complete where the
@@ -5066,10 +5063,9 @@ int dlm_recover_waiters_post(struct dlm_ls *ls)
/* drop all wait_count references we still
* hold a reference for this iteration.
*/
- while (lkb->lkb_wait_count) {
- lkb->lkb_wait_count--;
+ while (!atomic_dec_and_test(&lkb->lkb_wait_count))
unhold_lkb(lkb);
- }
+
mutex_lock(&ls->ls_waiters_mutex);
list_del_init(&lkb->lkb_wait_reply);
mutex_unlock(&ls->ls_waiters_mutex);
--
2.31.1
