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usb: cdc-wdm: Fix race between write and disconnect

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Unify mutexes to fix a race between write and disconnect
and shift the test for disconnection to always report it.

Signed-off-by: Oliver Neukum <neukum@b1-systems.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum 2010-02-27 20:54:24 +01:00 committed by Greg Kroah-Hartman
parent aa4714560b
commit 860e41a71c
1 changed files with 46 additions and 40 deletions
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86
drivers/usb/class/cdc-wdm.c
View File

@ -87,9 +87,7 @@ struct wdm_device {
int count;
dma_addr_t shandle;
dma_addr_t ihandle;
struct mutex wlock;
struct mutex rlock;
struct mutex plock;
struct mutex lock;
wait_queue_head_t wait;
struct work_struct rxwork;
int werr;
@ -305,14 +303,38 @@ static ssize_t wdm_write
if (we < 0)
return -EIO;
r = mutex_lock_interruptible(&desc->wlock); /* concurrent writes */
rv = -ERESTARTSYS;
if (r)
desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
if (!buf) {
rv = -ENOMEM;
goto outnl;
}
r = copy_from_user(buf, buffer, count);
if (r > 0) {
kfree(buf);
rv = -EFAULT;
goto outnl;
}
/* concurrent writes and disconnect */
r = mutex_lock_interruptible(&desc->lock);
rv = -ERESTARTSYS;
if (r) {
kfree(buf);
goto outnl;
}
if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
kfree(buf);
rv = -ENODEV;
goto outnp;
}
r = usb_autopm_get_interface(desc->intf);
if (r < 0)
if (r < 0) {
kfree(buf);
goto outnp;
}
if (!file->f_flags && O_NONBLOCK)
r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
@ -320,24 +342,8 @@ static ssize_t wdm_write
else
if (test_bit(WDM_IN_USE, &desc->flags))
r = -EAGAIN;
if (r < 0)
goto out;
if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
rv = -ENODEV;
goto out;
}
desc->outbuf = buf = kmalloc(count, GFP_KERNEL);
if (!buf) {
rv = -ENOMEM;
goto out;
}
r = copy_from_user(buf, buffer, count);
if (r > 0) {
if (r < 0) {
kfree(buf);
rv = -EFAULT;
goto out;
}
@ -374,7 +380,7 @@ static ssize_t wdm_write
out:
usb_autopm_put_interface(desc->intf);
outnp:
mutex_unlock(&desc->wlock);
mutex_unlock(&desc->lock);
outnl:
return rv < 0 ? rv : count;
}
@ -387,7 +393,7 @@ static ssize_t wdm_read
struct wdm_device *desc = file->private_data;
rv = mutex_lock_interruptible(&desc->rlock); /*concurrent reads */
rv = mutex_lock_interruptible(&desc->lock); /*concurrent reads */
if (rv < 0)
return -ERESTARTSYS;
@ -465,7 +471,7 @@ retry:
rv = cntr;
err:
mutex_unlock(&desc->rlock);
mutex_unlock(&desc->lock);
if (rv < 0 && rv != -EAGAIN)
dev_err(&desc->intf->dev, "wdm_read: exit error\n");
return rv;
@ -533,7 +539,7 @@ static int wdm_open(struct inode *inode, struct file *file)
}
intf->needs_remote_wakeup = 1;
mutex_lock(&desc->plock);
mutex_lock(&desc->lock);
if (!desc->count++) {
rv = usb_submit_urb(desc->validity, GFP_KERNEL);
if (rv < 0) {
@ -544,7 +550,7 @@ static int wdm_open(struct inode *inode, struct file *file)
} else {
rv = 0;
}
mutex_unlock(&desc->plock);
mutex_unlock(&desc->lock);
usb_autopm_put_interface(desc->intf);
out:
mutex_unlock(&wdm_mutex);
@ -556,9 +562,9 @@ static int wdm_release(struct inode *inode, struct file *file)
struct wdm_device *desc = file->private_data;
mutex_lock(&wdm_mutex);
mutex_lock(&desc->plock);
mutex_lock(&desc->lock);
desc->count--;
mutex_unlock(&desc->plock);
mutex_unlock(&desc->lock);
if (!desc->count) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup");
@ -655,9 +661,7 @@ next_desc:
desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
if (!desc)
goto out;
mutex_init(&desc->wlock);
mutex_init(&desc->rlock);
mutex_init(&desc->plock);
mutex_init(&desc->lock);
spin_lock_init(&desc->iuspin);
init_waitqueue_head(&desc->wait);
desc->wMaxCommand = maxcom;
@ -772,7 +776,9 @@ static void wdm_disconnect(struct usb_interface *intf)
clear_bit(WDM_IN_USE, &desc->flags);
spin_unlock_irqrestore(&desc->iuspin, flags);
cancel_work_sync(&desc->rxwork);
mutex_lock(&desc->lock);
kill_urbs(desc);
mutex_unlock(&desc->lock);
wake_up_all(&desc->wait);
if (!desc->count)
cleanup(desc);
@ -786,7 +792,7 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
mutex_lock(&desc->plock);
mutex_lock(&desc->lock);
#ifdef CONFIG_PM
if ((message.event & PM_EVENT_AUTO) &&
test_bit(WDM_IN_USE, &desc->flags)) {
@ -798,7 +804,7 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
#ifdef CONFIG_PM
}
#endif
mutex_unlock(&desc->plock);
mutex_unlock(&desc->lock);
return rv;
}
@ -821,9 +827,9 @@ static int wdm_resume(struct usb_interface *intf)
int rv;
dev_dbg(&desc->intf->dev, "wdm%d_resume\n", intf->minor);
mutex_lock(&desc->plock);
mutex_lock(&desc->lock);
rv = recover_from_urb_loss(desc);
mutex_unlock(&desc->plock);
mutex_unlock(&desc->lock);
return rv;
}
@ -831,7 +837,7 @@ static int wdm_pre_reset(struct usb_interface *intf)
{
struct wdm_device *desc = usb_get_intfdata(intf);
mutex_lock(&desc->plock);
mutex_lock(&desc->lock);
return 0;
}
@ -841,7 +847,7 @@ static int wdm_post_reset(struct usb_interface *intf)
int rv;
rv = recover_from_urb_loss(desc);
mutex_unlock(&desc->plock);
mutex_unlock(&desc->lock);
return 0;
}