virtio: console: Disable lseek(2) for port file operations
The ports are char devices; do not have seeking capabilities. Calling
nonseekable_open() from the fops_open() call and setting the llseek fops
pointer to no_llseek ensures an lseek() call from userspace returns
-ESPIPE.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index dc42d56..6c1b676 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -809,6 +809,8 @@
reclaim_consumed_buffers(port);
spin_unlock_irq(&port->outvq_lock);
+ nonseekable_open(inode, filp);
+
/* Notify host of port being opened */
send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
@@ -840,6 +842,7 @@
.poll = port_fops_poll,
.release = port_fops_release,
.fasync = port_fops_fasync,
+ .llseek = no_llseek,
};
/*