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Commit 86286883 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
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USB: usbtmc can do IO to device after disconnect 



usbtmc will happily complete read/write requests even after disconnect
has returned. The fix is to introduce a flag.


Signed-off-by: default avatarOliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 75b48f09

drivers/usb/class/usbtmc.c

+19 −0
Original line number Diff line number Diff line
@@ -86,6 +86,8 @@ struct usbtmc_device_data { 
	bool TermCharEnabled;

	bool auto_abort;



	bool zombie; /* fd of disconnected device */



	struct usbtmc_dev_capabilities	capabilities;

	struct kref kref;

	struct mutex io_mutex;	/* only one i/o function running at a time */
@@ -384,6 +386,10 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf, 
		return -ENOMEM;



	mutex_lock(&data->io_mutex);

	if (data->zombie) {

		retval = -ENODEV;

		goto exit;

	}



	remaining = count;

	done = 0;
@@ -496,6 +502,10 @@ static ssize_t usbtmc_write(struct file *filp, const char __user *buf, 
		return -ENOMEM;



	mutex_lock(&data->io_mutex);

	if (data->zombie) {

		retval = -ENODEV;

		goto exit;

	}



	remaining = count;

	done = 0;
@@ -925,6 +935,10 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 


	data = file->private_data;

	mutex_lock(&data->io_mutex);

	if (data->zombie) {

		retval = -ENODEV;

		goto skip_io_on_zombie;

	}



	switch (cmd) {

	case USBTMC_IOCTL_CLEAR_OUT_HALT:
@@ -952,6 +966,7 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
		break;

	}



skip_io_on_zombie:

	mutex_unlock(&data->io_mutex);

	return retval;

}
@@ -995,6 +1010,7 @@ static int usbtmc_probe(struct usb_interface *intf, 
	usb_set_intfdata(intf, data);

	kref_init(&data->kref);

	mutex_init(&data->io_mutex);

	data->zombie = 0;



	/* Initialize USBTMC bTag and other fields */

	data->bTag	= 1;
@@ -1065,6 +1081,9 @@ static void usbtmc_disconnect(struct usb_interface *intf) 
	usb_deregister_dev(intf, &usbtmc_class);

	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);

	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);

	mutex_lock(&data->io_mutex);

	data->zombie = 1;

	mutex_unlock(&data->io_mutex);

	kref_put(&data->kref, usbtmc_delete);

}