回复: [PATCH] usb: gadget: function: printer: Add gadget dev interface status judgment

["Zhang, Qiang" <Qiang.Zhang@windriver.com>]

________________________________________
发件人: linux-usb-owner@vger.kernel.org <linux-usb-owner@vger.kernel.org> 代表 qiang.zhang@windriver.com <qiang.zhang@windriver.com>
发送时间: 2020年6月15日 17:46
收件人: balbi@kernel.org
抄送: gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
主题: [PATCH] usb: gadget: function: printer: Add gadget dev interface status judgment

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

After the interface of gadget printer device was disabled,
We should not continue operate the device.

Signed-off-by: Zqiang <qiang.zhang@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