proc tty: add struct tty_operations::proc_fops

Used for gradual switch of TTY drivers from using ->read_proc which helps with gradual switch from ->read_proc for the whole tree. As side effect, fix possible race condition when ->data initialized after PDE is hooked into proc tree. ->proc_fops takes precedence over ->read_proc. Signed-off-by: Alexey Dobriyan <[email protected]> Cc: Alan Cox <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
goeke · Apr 1, 2009 · ae149b6 · ae149b6
1 parent 15f7176
commit ae149b6
Show file tree

Hide file tree

Showing 2 changed files with 14 additions and 7 deletions.
diff --git a/fs/proc/proc_tty.c b/fs/proc/proc_tty.c
@@ -144,16 +144,22 @@ void proc_tty_register_driver(struct tty_driver *driver)
 {
 	struct proc_dir_entry *ent;
 
-	if (!driver->ops->read_proc || !driver->driver_name ||
-	    driver->proc_entry)
+	if (!driver->driver_name || driver->proc_entry)
 		return;
 
-	ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
-	if (!ent)
+	if (driver->ops->proc_fops) {
+		ent = proc_create_data(driver->driver_name, 0, proc_tty_driver,
+				       driver->ops->proc_fops, driver);
+		if (!ent)
+			return;
+	} else if (driver->ops->read_proc) {
+		ent = create_proc_entry(driver->driver_name, 0, proc_tty_driver);
+		if (!ent)
+			return;
+		ent->read_proc = driver->ops->read_proc;
+		ent->data = driver;
+	} else
 		return;
-	ent->read_proc = driver->ops->read_proc;
-	ent->data = driver;
-
 	driver->proc_entry = ent;
 }
 

diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
@@ -264,6 +264,7 @@ struct tty_operations {
 	int (*poll_get_char)(struct tty_driver *driver, int line);
 	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 #endif
+	const struct file_operations *proc_fops;
 };
 
 struct tty_driver {