[PATCH] usb: gadget: function: printer: The device interface is reset and should return error code

[qiang.zhang]

From: Zqiang <qiang.zh...@windriver.com>

After the device is disconnected from the host side, the interface of
the device is reset. If the userspace operates the device again,
an error code should be returned.

Signed-off-by: Zqiang <qiang.zh...@windriver.com>
---
 drivers/usb/gadget/function/f_printer.c | 36 +++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/usb/gadget/function/f_printer.c 
b/drivers/usb/gadget/function/f_printer.c
index 9c7ed2539ff7..2b45a61e4213 100644
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -338,6 +338,11 @@ printer_open(struct inode *inode, struct file *fd)
 
        spin_lock_irqsave(&dev->lock, flags);
 
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               return -ENODEV;
+       }
+
        if (!dev->printer_cdev_open) {
                dev->printer_cdev_open = 1;
                fd->private_data = dev;
@@ -430,6 +435,12 @@ printer_read(struct file *fd, char __user *buf, size_t 
len, loff_t *ptr)
        mutex_lock(&dev->lock_printer_io);
        spin_lock_irqsave(&dev->lock, flags);
 
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               mutex_unlock(&dev->lock_printer_io);
+               return -ENODEV;
+       }
+
        /* We will use this flag later to check if a printer reset happened
         * after we turn interrupts back on.
         */
@@ -561,6 +572,12 @@ printer_write(struct file *fd, const char __user *buf, 
size_t len, loff_t *ptr)
        mutex_lock(&dev->lock_printer_io);
        spin_lock_irqsave(&dev->lock, flags);
 
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               mutex_unlock(&dev->lock_printer_io);
+               return -ENODEV;
+       }
+
        /* Check if a printer reset happens while we have interrupts on */
        dev->reset_printer = 0;
 
@@ -667,6 +684,13 @@ printer_fsync(struct file *fd, loff_t start, loff_t end, 
int datasync)
 
        inode_lock(inode);
        spin_lock_irqsave(&dev->lock, flags);
+
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               inode_unlock(inode);
+               return -ENODEV;
+       }
+
        tx_list_empty = (likely(list_empty(&dev->tx_reqs)));
        spin_unlock_irqrestore(&dev->lock, flags);
 
@@ -689,6 +713,13 @@ printer_poll(struct file *fd, poll_table *wait)
 
        mutex_lock(&dev->lock_printer_io);
        spin_lock_irqsave(&dev->lock, flags);
+
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               mutex_unlock(&dev->lock_printer_io);
+               return EPOLLERR | EPOLLHUP;
+       }
+
        setup_rx_reqs(dev);
        spin_unlock_irqrestore(&dev->lock, flags);
        mutex_unlock(&dev->lock_printer_io);
@@ -722,6 +753,11 @@ printer_ioctl(struct file *fd, unsigned int code, unsigned 
long arg)
 
        spin_lock_irqsave(&dev->lock, flags);
 
+       if (dev->interface < 0) {
+               spin_unlock_irqrestore(&dev->lock, flags);
+               return -ENODEV;
+       }
+
        switch (code) {
        case GADGET_GET_PRINTER_STATUS:
                status = (int)dev->printer_status;
-- 
2.24.1