Re: [net-next, v3, 02/10] ptp: support ptp physical/virtual clocks conversion
From: Richard Cochran <richardcochran@gmail.com>
Date: 2021-06-19 04:06:39
Also in:
linux-kselftest, lkml, mptcp
On Tue, Jun 15, 2021 at 05:45:09PM +0800, Yangbo Lu wrote:
quoted hunk ↗ jump to hunk
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c index a780435331c8..78414b3e16dd 100644 --- a/drivers/ptp/ptp_clock.c +++ b/drivers/ptp/ptp_clock.c@@ -76,6 +76,11 @@ static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp { struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); + if (ptp_guaranteed_pclock(ptp)) {
Can we please invent a more descriptive name for this method? The word "guaranteed" suggests much more.
+ pr_err("ptp: virtual clock in use, guarantee physical clock free running\n");This is good: ^^^^^^^^^^^^^^^^^^^^^^^^^ You can drop this part: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ So, please rename ptp_guaranteed_pclock() to ptp_vclock_in_use();
+ return -EBUSY; + } + return ptp->info->settime64(ptp->info, tp); }
quoted hunk ↗ jump to hunk
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h index 3f388d63904c..6949afc9d733 100644 --- a/drivers/ptp/ptp_private.h +++ b/drivers/ptp/ptp_private.h@@ -46,6 +46,9 @@ struct ptp_clock { const struct attribute_group *pin_attr_groups[2]; struct kthread_worker *kworker; struct kthread_delayed_work aux_work; + u8 n_vclocks;
Why not use "unsigned int" type? I don't see a need to set an artificial limit.
+ struct mutex n_vclocks_mux; /* protect concurrent n_vclocks access */ + bool vclock_flag;
"flag" is vague. How about "is_virtual_clock" instead?
quoted hunk ↗ jump to hunk
}; #define info_to_vclock(d) container_of((d), struct ptp_vclock, info)@@ -75,6 +78,18 @@ static inline int queue_cnt(struct timestamp_event_queue *q) return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt; } +/* + * Guarantee physical clock to stay free running, if ptp virtual clocks + * on it are in use. + */ +static inline bool ptp_guaranteed_pclock(struct ptp_clock *ptp) +{ + if (!ptp->vclock_flag && ptp->n_vclocks)
Need to take mutex for n_vclocks to prevent load tearing.
+ return true; + + return false; +} + /* * see ptp_chardev.c */
quoted hunk ↗ jump to hunk
@@ -148,6 +149,90 @@ static ssize_t pps_enable_store(struct device *dev, } static DEVICE_ATTR(pps_enable, 0220, NULL, pps_enable_store); +static int unregister_vclock(struct device *dev, void *data) +{ + struct ptp_clock *ptp = dev_get_drvdata(dev); + struct ptp_clock_info *info = ptp->info; + struct ptp_vclock *vclock; + u8 *num = data; + + vclock = info_to_vclock(info); + dev_info(dev->parent, "delete virtual clock ptp%d\n", + vclock->clock->index); + + ptp_vclock_unregister(vclock); + (*num)--; + + /* For break. Not error. */ + if (*num == 0) + return -EINVAL; + + return 0; +} + +static ssize_t n_vclocks_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct ptp_clock *ptp = dev_get_drvdata(dev); + + return snprintf(page, PAGE_SIZE-1, "%d\n", ptp->n_vclocks);
Take mutex.
+}
+
+static ssize_t n_vclocks_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ptp_clock *ptp = dev_get_drvdata(dev);
+ struct ptp_vclock *vclock;
+ int err = -EINVAL;
+ u8 num, i;
+
+ if (kstrtou8(buf, 0, &num))
+ goto out;
+
+ if (num > PTP_MAX_VCLOCKS) {
+ dev_err(dev, "max value is %d\n", PTP_MAX_VCLOCKS);
+ goto out;
+ }
+
+ if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
+ return -ERESTARTSYS;
+
+ /* Need to create more vclocks */
+ if (num > ptp->n_vclocks) {
+ for (i = 0; i < num - ptp->n_vclocks; i++) {
+ vclock = ptp_vclock_register(ptp);
+ if (!vclock) {
+ mutex_unlock(&ptp->n_vclocks_mux);
+ goto out;
+ }
+
+ dev_info(dev, "new virtual clock ptp%d\n",
+ vclock->clock->index);
+ }
+ }
+
+ /* Need to delete vclocks */
+ if (num < ptp->n_vclocks) {
+ i = ptp->n_vclocks - num;
+ device_for_each_child_reverse(dev, &i,
+ unregister_vclock);
+ }
+
+ if (num == 0)
+ dev_info(dev, "only physical clock in use now\n");
+ else
+ dev_info(dev, "guarantee physical clock free running\n");
+
+ ptp->n_vclocks = num;
+ mutex_unlock(&ptp->n_vclocks_mux);
+
+ return count;
+out:
+ return err;
+}
+static DEVICE_ATTR_RW(n_vclocks);
+
static struct attribute *ptp_attrs[] = {
&dev_attr_clock_name.attr,
quoted hunk ↗ jump to hunk
diff --git a/include/uapi/linux/ptp_clock.h b/include/uapi/linux/ptp_clock.h index 1d108d597f66..4b933dc1b81b 100644 --- a/include/uapi/linux/ptp_clock.h +++ b/include/uapi/linux/ptp_clock.h@@ -69,6 +69,11 @@ */ #define PTP_PEROUT_V1_VALID_FLAGS (0) +/* + * Max number of PTP virtual clocks per PTP physical clock + */ +#define PTP_MAX_VCLOCKS 20
Why limit this to twenty clocks? Thanks, Richard