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@redhat.com --- 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);