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Message-Id: <20230912220217.2008895-2-reibax@gmail.com>
Date: Wed, 13 Sep 2023 00:02:16 +0200
From: Xabier Marquiegui <reibax@...il.com>
To: netdev@...r.kernel.org
Cc: richardcochran@...il.com,
horms@...nel.org,
chrony-dev@...ony.tuxfamily.org,
mlichvar@...hat.com,
reibax@...il.com,
ntp-lists@...tcorallo.com,
shuah@...nel.org,
davem@...emloft.net,
rrameshbabu@...dia.com,
alex.maftei@....com
Subject: [PATCH net-next v2 2/3] ptp: support multiple timestamp event readers
Use linked lists to create one event queue per open file. This enables
simultaneous readers for timestamp event queues.
Signed-off-by: Xabier Marquiegui <reibax@...il.com>
Suggested-by: Richard Cochran <richardcochran@...il.com>
---
v2:
- fix ptp_poll() return value
- Style changes to comform to checkpatch strict suggestions
- more coherent ptp_read error exit routines
v1: https://lore.kernel.org/netdev/20230906104754.1324412-3-reibax@gmail.com/
drivers/ptp/ptp_chardev.c | 100 +++++++++++++++++++++++++++++---------
drivers/ptp/ptp_clock.c | 6 +--
drivers/ptp/ptp_private.h | 4 +-
drivers/ptp/ptp_sysfs.c | 4 --
4 files changed, 82 insertions(+), 32 deletions(-)
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 197edf1179f1..c9da0f27d204 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -103,9 +103,39 @@ int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
int ptp_open(struct posix_clock *pc, fmode_t fmode)
{
+ struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ struct timestamp_event_queue *queue;
+
+ queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+ if (!queue)
+ return -EINVAL;
+ queue->reader_pid = task_pid_nr(current);
+ list_add_tail(&queue->qlist, &ptp->tsevqs);
+
return 0;
}
+int ptp_release(struct posix_clock *pc)
+{
+ struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ struct list_head *pos, *n;
+ struct timestamp_event_queue *element;
+ int found = -1;
+ pid_t reader_pid = task_pid_nr(current);
+
+ list_for_each_safe(pos, n, &ptp->tsevqs) {
+ element = list_entry(pos, struct timestamp_event_queue, qlist);
+ if (element->reader_pid == reader_pid) {
+ list_del(pos);
+ kfree(element);
+ found = 0;
+ return found;
+ }
+ }
+
+ return found;
+}
+
long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
@@ -435,14 +465,24 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
__poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ pid_t reader_pid = task_pid_nr(current);
struct timestamp_event_queue *queue;
+ struct list_head *pos, *n;
+ bool found = false;
poll_wait(fp, &ptp->tsev_wq, wait);
- /* Extract only the first element in the queue list
- * TODO: Identify the relevant queue
- */
- queue = list_entry(&ptp->tsevqs, struct timestamp_event_queue, qlist);
+ /* Extract only the desired element in the queue list */
+ list_for_each_safe(pos, n, &ptp->tsevqs) {
+ queue = list_entry(pos, struct timestamp_event_queue, qlist);
+ if (queue->reader_pid == reader_pid) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ return EPOLLERR;
return queue_cnt(queue) ? EPOLLIN : 0;
}
@@ -453,44 +493,54 @@ ssize_t ptp_read(struct posix_clock *pc,
uint rdflags, char __user *buf, size_t cnt)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ pid_t reader_pid = task_pid_nr(current);
struct timestamp_event_queue *queue;
struct ptp_extts_event *event;
+ struct list_head *pos, *n;
unsigned long flags;
+ bool found = false;
size_t qcnt, i;
int result;
- /* Extract only the first element in the queue list
- * TODO: Identify the relevant queue
- */
- queue = list_first_entry(&ptp->tsevqs, struct timestamp_event_queue,
- qlist);
+ /* Extract only the desired element in the queue list */
+ list_for_each_safe(pos, n, &ptp->tsevqs) {
+ queue = list_entry(pos, struct timestamp_event_queue, qlist);
+ if (queue->reader_pid == reader_pid) {
+ found = true;
+ break;
+ }
+ }
- if (cnt % sizeof(struct ptp_extts_event) != 0)
- return -EINVAL;
+ if (!found) {
+ result = -EINVAL;
+ goto exit;
+ }
+
+ if (cnt % sizeof(struct ptp_extts_event) != 0) {
+ result = -EINVAL;
+ goto exit;
+ }
if (cnt > EXTTS_BUFSIZE)
cnt = EXTTS_BUFSIZE;
cnt = cnt / sizeof(struct ptp_extts_event);
- if (mutex_lock_interruptible(&ptp->tsevq_mux))
- return -ERESTARTSYS;
-
if (wait_event_interruptible(ptp->tsev_wq,
ptp->defunct || queue_cnt(queue))) {
- mutex_unlock(&ptp->tsevq_mux);
- return -ERESTARTSYS;
+ result = -ERESTARTSYS;
+ goto exit;
}
if (ptp->defunct) {
- mutex_unlock(&ptp->tsevq_mux);
- return -ENODEV;
+ result = -ENODEV;
+ goto exit;
}
event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
if (!event) {
- mutex_unlock(&ptp->tsevq_mux);
- return -ENOMEM;
+ result = -ENOMEM;
+ goto exit;
}
spin_lock_irqsave(&queue->lock, flags);
@@ -509,12 +559,16 @@ ssize_t ptp_read(struct posix_clock *pc,
cnt = cnt * sizeof(struct ptp_extts_event);
- mutex_unlock(&ptp->tsevq_mux);
-
result = cnt;
- if (copy_to_user(buf, event, cnt))
+ if (copy_to_user(buf, event, cnt)) {
result = -EFAULT;
+ goto free_event;
+ }
+free_event:
kfree(event);
+exit:
+ if (result < 0)
+ ptp_release(pc);
return result;
}
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 7ac04a282ec5..d52fc23e20a8 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -162,6 +162,7 @@ static struct posix_clock_operations ptp_clock_ops = {
.clock_settime = ptp_clock_settime,
.ioctl = ptp_ioctl,
.open = ptp_open,
+ .release = ptp_release,
.poll = ptp_poll,
.read = ptp_read,
};
@@ -184,7 +185,6 @@ static void ptp_clock_release(struct device *dev)
ptp_cleanup_pin_groups(ptp);
kfree(ptp->vclock_index);
- mutex_destroy(&ptp->tsevq_mux);
mutex_destroy(&ptp->pincfg_mux);
mutex_destroy(&ptp->n_vclocks_mux);
ptp_clean_queue_list(ptp);
@@ -246,10 +246,9 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
queue = kzalloc(sizeof(*queue), GFP_KERNEL);
if (!queue)
goto no_memory_queue;
+ queue->reader_pid = 0;
spin_lock_init(&queue->lock);
list_add_tail(&queue->qlist, &ptp->tsevqs);
- /* TODO - Transform or delete this mutex */
- mutex_init(&ptp->tsevq_mux);
mutex_init(&ptp->pincfg_mux);
mutex_init(&ptp->n_vclocks_mux);
init_waitqueue_head(&ptp->tsev_wq);
@@ -350,7 +349,6 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (ptp->kworker)
kthread_destroy_worker(ptp->kworker);
kworker_err:
- mutex_destroy(&ptp->tsevq_mux);
mutex_destroy(&ptp->pincfg_mux);
mutex_destroy(&ptp->n_vclocks_mux);
ptp_clean_queue_list(ptp);
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 314c21c39f6a..046d1482bcee 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -27,6 +27,7 @@ struct timestamp_event_queue {
int tail;
spinlock_t lock;
struct list_head qlist;
+ pid_t reader_pid;
};
struct ptp_clock {
@@ -38,7 +39,6 @@ struct ptp_clock {
struct pps_device *pps_source;
long dialed_frequency; /* remembers the frequency adjustment */
struct list_head tsevqs; /* timestamp fifo list */
- struct mutex tsevq_mux; /* one process at a time reading the fifo */
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 */
@@ -124,6 +124,8 @@ long ptp_ioctl(struct posix_clock *pc,
int ptp_open(struct posix_clock *pc, fmode_t fmode);
+int ptp_release(struct posix_clock *pc);
+
ssize_t ptp_read(struct posix_clock *pc,
uint flags, char __user *buf, size_t cnt);
diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index 2675f383cd0a..512b0164ef18 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -87,9 +87,6 @@ static ssize_t extts_fifo_show(struct device *dev,
memset(&event, 0, sizeof(event));
- if (mutex_lock_interruptible(&ptp->tsevq_mux))
- return -ERESTARTSYS;
-
spin_lock_irqsave(&queue->lock, flags);
qcnt = queue_cnt(queue);
if (qcnt) {
@@ -104,7 +101,6 @@ static ssize_t extts_fifo_show(struct device *dev,
cnt = snprintf(page, PAGE_SIZE, "%u %lld %u\n",
event.index, event.t.sec, event.t.nsec);
out:
- mutex_unlock(&ptp->tsevq_mux);
return cnt;
}
static DEVICE_ATTR(fifo, 0444, extts_fifo_show, NULL);
--
2.34.1
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