The console_lock is used in part to guarantee safe list iteration.
The console_list_lock should be used because list synchronization
responsibility will be removed from the console_lock in a later
change.
Note, the console_lock is still needed to serialize the device()
callback with other console operations.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
---
fs/proc/consoles.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c
index 46b305fa04ed..e0758fe7936d 100644
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -33,7 +33,16 @@ static int show_console_dev(struct seq_file *m, void *v)
if (con->device) {
const struct tty_driver *driver;
int index;
+
+ /*
+ * Take console_lock to serialize device() callback with
+ * other console operations. For example, fg_console is
+ * modified under console_lock when switching vt.
+ */
+ console_lock();
driver = con->device(con, &index);
+ console_unlock();
+
if (driver) {
dev = MKDEV(driver->major, driver->minor_start);
dev += index;
@@ -64,15 +73,11 @@ static void *c_start(struct seq_file *m, loff_t *pos)
loff_t off = 0;
/*
- * Take console_lock to serialize device() callback with
- * other console operations. For example, fg_console is
- * modified under console_lock when switching vt.
- *
- * Hold the console_lock to guarantee safe traversal of the
+ * Hold the console_list_lock to guarantee safe traversal of the
* console list. SRCU cannot be used because there is no
* place to store the SRCU cookie.
*/
- console_lock();
+ console_list_lock();
for_each_console(con)
if (off++ == *pos)
break;
@@ -90,7 +95,7 @@ static void *c_next(struct seq_file *m, void *v, loff_t *pos)
static void c_stop(struct seq_file *m, void *v)
{
- console_unlock();
+ console_list_unlock();
}
static const struct seq_operations consoles_op = {
--
2.30.2