From 86286883fc8218c81cc1deb04cd1b4a8464bba6f Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@neukum.org>
Date: Thu, 2 Jul 2009 11:36:30 +0200
Subject: [PATCH] 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: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/usb/class/usbtmc.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index b09a527f7341..0c9df97f6775 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -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);
}