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authorIngo Molnar <mingo@kernel.org>2023-12-23 15:52:13 +0100
committerIngo Molnar <mingo@kernel.org>2023-12-23 15:52:13 +0100
commitd2e9f53ac5dd76dadc0b5f04f6c27640604ce2af (patch)
treebf82d9fbfdc2ce67630fdacc18c2231f3d17876a /drivers/ptp/ptp_private.h
parent418146e39891ef1fb2284dee4cabbfe616cd21cf (diff)
parentceb6a6f023fd3e8b07761ed900352ef574010bcb (diff)
Merge tag 'v6.7-rc6' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/ptp/ptp_private.h')
-rw-r--r--drivers/ptp/ptp_private.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 35fde0a05746..45f9002a5dca 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -85,9 +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;
}