diff options
Diffstat (limited to 'drivers/ptp/ptp_private.h')
| -rw-r--r-- | drivers/ptp/ptp_private.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h index 52f87e394aa6..45f9002a5dca 100644 --- a/drivers/ptp/ptp_private.h +++ b/drivers/ptp/ptp_private.h @@ -44,6 +44,7 @@ struct ptp_clock { struct pps_device *pps_source; long dialed_frequency; /* remembers the frequency adjustment */ struct list_head tsevqs; /* timestamp fifo list */ + spinlock_t tsevqs_lock; /* protects tsevqs from concurrent access */ struct mutex pincfg_mux; /* protect concurrent info->pin_config access */ wait_queue_head_t tsev_wq; int defunct; /* tells readers to go away when clock is being removed */ @@ -84,9 +85,13 @@ struct ptp_vclock { * that a writer might concurrently increment the tail does not * matter, since the queue remains nonempty nonetheless. */ -static inline int queue_cnt(struct timestamp_event_queue *q) +static inline int queue_cnt(const struct timestamp_event_queue *q) { - int cnt = q->tail - q->head; + /* + * Paired with WRITE_ONCE() in enqueue_external_timestamp(), + * ptp_read(), extts_fifo_show(). + */ + int cnt = READ_ONCE(q->tail) - READ_ONCE(q->head); return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt; } |