From: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
If usblp device has been disconnected, direct return
'EPOLLHUP | EPOLLERR' in usblp_poll().
Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
---
drivers/usb/class/usblp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index c9f6e9758288..40095c8826d2 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -498,6 +498,12 @@ static __poll_t usblp_poll(struct file *file, struct poll_table_struct *wait)
unsigned long flags;
struct usblp *usblp = file->private_data;
+ mutex_lock(&usblp->mut);
+ if (!usblp->present) {
+ ret = EPOLLHUP | EPOLLERR;
+ goto no_poll;
+ }
+
/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
poll_wait(file, &usblp->rwait, wait);
poll_wait(file, &usblp->wwait, wait);
@@ -505,6 +511,8 @@ static __poll_t usblp_poll(struct file *file, struct poll_table_struct *wait)
ret = ((usblp->bidir && usblp->rcomplete) ? EPOLLIN | EPOLLRDNORM : 0) |
((usblp->no_paper || usblp->wcomplete) ? EPOLLOUT | EPOLLWRNORM : 0);
spin_unlock_irqrestore(&usblp->lock, flags);
+no_poll:
+ mutex_unlock(&usblp->mut);
return ret;
}
--
2.25.1
