[PATCH 6.1 079/280] posix-clock: introduce posix_clock_context concept

Greg Kroah-Hartman
2026-02-04T15:07:37Z

From: Xabier Marquiegui <reibax@gmail.com>

[ Upstream commit 60c6946675fc06dd2fd2b7a4b6fd1c1f046f1056 ]

Add the necessary structure to support custom private-data per
posix-clock user.

The previous implementation of posix-clock assumed all file open
instances need access to the same clock structure on private_data.

The need for individual data structures per file open instance has been
identified when developing support for multiple timestamp event queue
users for ptp_clock.

Signed-off-by: Xabier Marquiegui <reibax@gmail.com>
Suggested-by: Richard Cochran <richardcochran@gmail.com>
Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: e859d375d169 ("posix-clock: Store file pointer in struct posix_clock_context")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/ptp/ptp_chardev.c | 21 +++++++++++++--------
drivers/ptp/ptp_private.h | 16 +++++++++-------
include/linux/posix-clock.h | 35 +++++++++++++++++++++++++++--------
kernel/time/posix-clock.c | 36 +++++++++++++++++++++++++++---------
4 files changed, 76 insertions(+), 32 deletions(-)

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 6b36003567975..fcee202f4484c 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -103,14 +103,16 @@ int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
return 0;
}

-int ptp_open(struct posix_clock *pc, fmode_t fmode)
+int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
{
return 0;
}

-long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
+long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
+ unsigned long arg)
{
- struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ struct ptp_clock *ptp =
+ container_of(pccontext->clk, struct ptp_clock, clock);
struct ptp_sys_offset_extended *extoff = NULL;
struct ptp_sys_offset_precise precise_offset;
struct system_device_crosststamp xtstamp;
@@ -434,9 +436,11 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
return err;
}

-__poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
+__poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
+ poll_table *wait)
{
- struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ struct ptp_clock *ptp =
+ container_of(pccontext->clk, struct ptp_clock, clock);

poll_wait(fp, &ptp->tsev_wq, wait);

@@ -445,10 +449,11 @@ __poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)

#define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))

-ssize_t ptp_read(struct posix_clock *pc,
- uint rdflags, char __user *buf, size_t cnt)
+ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
+ char __user *buf, size_t cnt)
{
- struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ struct ptp_clock *ptp =
+ container_of(pccontext->clk, struct ptp_clock, clock);
struct timestamp_event_queue *queue = &ptp->tsevq;
struct ptp_extts_event *event;
unsigned long flags;
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index a54124269c2f4..a431eb79fe77d 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -131,16 +131,18 @@ extern struct class *ptp_class;
int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
enum ptp_pin_function func, unsigned int chan);

-long ptp_ioctl(struct posix_clock *pc,
- unsigned int cmd, unsigned long arg);
+long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
+ unsigned long arg);

-int ptp_open(struct posix_clock *pc, fmode_t fmode);
+int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode);

-ssize_t ptp_read(struct posix_clock *pc,
- uint flags, char __user *buf, size_t cnt);
+int ptp_release(struct posix_clock_context *pccontext);

-__poll_t ptp_poll(struct posix_clock *pc,
- struct file *fp, poll_table *wait);
+ssize_t ptp_read(struct posix_clock_context *pccontext, uint flags, char __user *buf,
+ size_t cnt);
+
+__poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
+ poll_table *wait);

/*
* see ptp_sysfs.c
diff --git a/include/linux/posix-clock.h b/include/linux/posix-clock.h
index 468328b1e1dd5..ef8619f489203 100644
--- a/include/linux/posix-clock.h
+++ b/include/linux/posix-clock.h
@@ -14,6 +14,7 @@
#include <linux/rwsem.h>

struct posix_clock;
+struct posix_clock_context;

/**
* struct posix_clock_operations - functional interface to the clock
@@ -50,18 +51,18 @@ struct posix_clock_operations {
/*
* Optional character device methods:
*/
- long (*ioctl) (struct posix_clock *pc,
- unsigned int cmd, unsigned long arg);
+ long (*ioctl)(struct posix_clock_context *pccontext, unsigned int cmd,
+ unsigned long arg);

- int (*open) (struct posix_clock *pc, fmode_t f_mode);
+ int (*open)(struct posix_clock_context *pccontext, fmode_t f_mode);

- __poll_t (*poll) (struct posix_clock *pc,
- struct file *file, poll_table *wait);
+ __poll_t (*poll)(struct posix_clock_context *pccontext, struct file *file,
+ poll_table *wait);

- int (*release) (struct posix_clock *pc);
+ int (*release)(struct posix_clock_context *pccontext);

- ssize_t (*read) (struct posix_clock *pc,
- uint flags, char __user *buf, size_t cnt);
+ ssize_t (*read)(struct posix_clock_context *pccontext, uint flags,
+ char __user *buf, size_t cnt);
};

/**
@@ -90,6 +91,24 @@ struct posix_clock {
bool zombie;
};

+/**
+ * struct posix_clock_context - represents clock file operations context
+ *
+ * @clk: Pointer to the clock
+ * @private_clkdata: Pointer to user data
+ *
+ * Drivers should use struct posix_clock_context during specific character
+ * device file operation methods to access the posix clock.
+ *
+ * Drivers can store a private data structure during the open operation
+ * if they have specific information that is required in other file
+ * operations.
+ */
+struct posix_clock_context {
+ struct posix_clock *clk;
+ void *private_clkdata;
+};
+
/**
* posix_clock_register() - register a new clock
* @clk: Pointer to the clock. Caller must provide 'ops' field
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 05e73d209aa87..706559ed75793 100644
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -19,7 +19,8 @@
*/
static struct posix_clock *get_posix_clock(struct file *fp)
{
- struct posix_clock *clk = fp->private_data;
+ struct posix_clock_context *pccontext = fp->private_data;
+ struct posix_clock *clk = pccontext->clk;

down_read(&clk->rwsem);

@@ -39,6 +40,7 @@ static void put_posix_clock(struct posix_clock *clk)
static ssize_t posix_clock_read(struct file *fp, char __user *buf,
size_t count, loff_t *ppos)
{
+ struct posix_clock_context *pccontext = fp->private_data;
struct posix_clock *clk = get_posix_clock(fp);
int err = -EINVAL;

@@ -46,7 +48,7 @@ static ssize_t posix_clock_read(struct file *fp, char __user *buf,
return -ENODEV;

if (clk->ops.read)
- err = clk->ops.read(clk, fp->f_flags, buf, count);
+ err = clk->ops.read(pccontext, fp->f_flags, buf, count);

put_posix_clock(clk);

@@ -55,6 +57,7 @@ static ssize_t posix_clock_read(struct file *fp, char __user *buf,

static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
{
+ struct posix_clock_context *pccontext = fp->private_data;
struct posix_clock *clk = get_posix_clock(fp);
__poll_t result = 0;

@@ -62,7 +65,7 @@ static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
return EPOLLERR;

if (clk->ops.poll)
- result = clk->ops.poll(clk, fp, wait);
+ result = clk->ops.poll(pccontext, fp, wait);

put_posix_clock(clk);

@@ -72,6 +75,7 @@ static __poll_t posix_clock_poll(struct file *fp, poll_table *wait)
static long posix_clock_ioctl(struct file *fp,
unsigned int cmd, unsigned long arg)
{
+ struct posix_clock_context *pccontext = fp->private_data;
struct posix_clock *clk = get_posix_clock(fp);
int err = -ENOTTY;

@@ -79,7 +83,7 @@ static long posix_clock_ioctl(struct file *fp,
return -ENODEV;

if (clk->ops.ioctl)
- err = clk->ops.ioctl(clk, cmd, arg);
+ err = clk->ops.ioctl(pccontext, cmd, arg);

put_posix_clock(clk);

@@ -90,6 +94,7 @@ static long posix_clock_ioctl(struct file *fp,
static long posix_clock_compat_ioctl(struct file *fp,
unsigned int cmd, unsigned long arg)
{
+ struct posix_clock_context *pccontext = fp->private_data;
struct posix_clock *clk = get_posix_clock(fp);
int err = -ENOTTY;

@@ -97,7 +102,7 @@ static long posix_clock_compat_ioctl(struct file *fp,
return -ENODEV;

if (clk->ops.ioctl)
- err = clk->ops.ioctl(clk, cmd, arg);
+ err = clk->ops.ioctl(pccontext, cmd, arg);

put_posix_clock(clk);

@@ -110,6 +115,7 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
int err;
struct posix_clock *clk =
container_of(inode->i_cdev, struct posix_clock, cdev);
+ struct posix_clock_context *pccontext;

down_read(&clk->rwsem);

@@ -117,14 +123,20 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
err = -ENODEV;
goto out;
}
+ pccontext = kzalloc(sizeof(*pccontext), GFP_KERNEL);
+ if (!pccontext) {
+ err = -ENOMEM;
+ goto out;
+ }
+ pccontext->clk = clk;
+ fp->private_data = pccontext;
if (clk->ops.open)
- err = clk->ops.open(clk, fp->f_mode);
+ err = clk->ops.open(pccontext, fp->f_mode);
else
err = 0;

if (!err) {
get_device(clk->dev);
- fp->private_data = clk;
}
out:
up_read(&clk->rwsem);
@@ -133,14 +145,20 @@ static int posix_clock_open(struct inode *inode, struct file *fp)

static int posix_clock_release(struct inode *inode, struct file *fp)
{
- struct posix_clock *clk = fp->private_data;
+ struct posix_clock_context *pccontext = fp->private_data;
+ struct posix_clock *clk;
int err = 0;

+ if (!pccontext)
+ return -ENODEV;
+ clk = pccontext->clk;
+
if (clk->ops.release)
- err = clk->ops.release(clk);
+ err = clk->ops.release(pccontext);

put_device(clk->dev);

+ kfree(pccontext);
fp->private_data = NULL;

return err;
--
2.51.0