From 60c6946675fc06dd2fd2b7a4b6fd1c1f046f1056 Mon Sep 17 00:00:00 2001
From: Xabier Marquiegui <reibax@gmail.com>
Date: Thu, 12 Oct 2023 00:39:53 +0200
Subject: posix-clock: introduce posix_clock_context concept

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>
---
 kernel/time/posix-clock.c | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

(limited to 'kernel/time')

diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 77c0c2370b6d..9de66bbbb3d1 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 @@ out:
 
 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;
-- 
cgit