diff options
Diffstat (limited to 'drivers/usb/class/cdc-wdm.c')
-rw-r--r-- | drivers/usb/class/cdc-wdm.c | 117 |
1 files changed, 90 insertions, 27 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 4929c5883068..b60a4200fc2b 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -58,6 +58,9 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_MAX 16 +/* we cannot wait forever at flush() */ +#define WDM_FLUSH_TIMEOUT (30 * HZ) + /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ #define WDM_DEFAULT_BUFSIZE 256 @@ -151,7 +154,7 @@ static void wdm_out_callback(struct urb *urb) kfree(desc->outbuf); desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); - wake_up(&desc->wait); + wake_up_all(&desc->wait); } static void wdm_in_callback(struct urb *urb) @@ -318,12 +321,23 @@ exit: } -static void kill_urbs(struct wdm_device *desc) +static void poison_urbs(struct wdm_device *desc) { /* the order here is essential */ - usb_kill_urb(desc->command); - usb_kill_urb(desc->validity); - usb_kill_urb(desc->response); + usb_poison_urb(desc->command); + usb_poison_urb(desc->validity); + usb_poison_urb(desc->response); +} + +static void unpoison_urbs(struct wdm_device *desc) +{ + /* + * the order here is not essential + * it is symmetrical just to be nice + */ + usb_unpoison_urb(desc->response); + usb_unpoison_urb(desc->validity); + usb_unpoison_urb(desc->command); } static void free_urbs(struct wdm_device *desc) @@ -393,6 +407,9 @@ static ssize_t wdm_write if (test_bit(WDM_RESETTING, &desc->flags)) r = -EIO; + if (test_bit(WDM_DISCONNECTING, &desc->flags)) + r = -ENODEV; + if (r < 0) { rv = r; goto out_free_mem_pm; @@ -424,6 +441,7 @@ static ssize_t wdm_write if (rv < 0) { desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); + wake_up_all(&desc->wait); /* for wdm_wait_for_response() */ dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); rv = usb_translate_errors(rv); goto out_free_mem_pm; @@ -458,13 +476,23 @@ static int service_outstanding_interrupt(struct wdm_device *desc) if (!desc->resp_count || !--desc->resp_count) goto out; + if (test_bit(WDM_DISCONNECTING, &desc->flags)) { + rv = -ENODEV; + goto out; + } + if (test_bit(WDM_RESETTING, &desc->flags)) { + rv = -EIO; + goto out; + } + set_bit(WDM_RESPONDING, &desc->flags); spin_unlock_irq(&desc->iuspin); rv = usb_submit_urb(desc->response, GFP_KERNEL); spin_lock_irq(&desc->iuspin); if (rv) { - dev_err(&desc->intf->dev, - "usb_submit_urb failed with result %d\n", rv); + if (!test_bit(WDM_DISCONNECTING, &desc->flags)) + dev_err(&desc->intf->dev, + "usb_submit_urb failed with result %d\n", rv); /* make sure the next notification trigger a submit */ clear_bit(WDM_RESPONDING, &desc->flags); @@ -583,28 +611,58 @@ err: return rv; } -static int wdm_flush(struct file *file, fl_owner_t id) +static int wdm_wait_for_response(struct file *file, long timeout) { struct wdm_device *desc = file->private_data; + long rv; /* Use long here because (int) MAX_SCHEDULE_TIMEOUT < 0. */ + + /* + * Needs both flags. We cannot do with one because resetting it would + * cause a race with write() yet we need to signal a disconnect. + */ + rv = wait_event_interruptible_timeout(desc->wait, + !test_bit(WDM_IN_USE, &desc->flags) || + test_bit(WDM_DISCONNECTING, &desc->flags), + timeout); - wait_event(desc->wait, - /* - * needs both flags. We cannot do with one - * because resetting it would cause a race - * with write() yet we need to signal - * a disconnect - */ - !test_bit(WDM_IN_USE, &desc->flags) || - test_bit(WDM_DISCONNECTING, &desc->flags)); - - /* cannot dereference desc->intf if WDM_DISCONNECTING */ + /* + * To report the correct error. This is best effort. + * We are inevitably racing with the hardware. + */ if (test_bit(WDM_DISCONNECTING, &desc->flags)) return -ENODEV; - if (desc->werr < 0) - dev_err(&desc->intf->dev, "Error in flush path: %d\n", - desc->werr); + if (!rv) + return -EIO; + if (rv < 0) + return -EINTR; + + spin_lock_irq(&desc->iuspin); + rv = desc->werr; + desc->werr = 0; + spin_unlock_irq(&desc->iuspin); + + return usb_translate_errors(rv); - return usb_translate_errors(desc->werr); +} + +/* + * You need to send a signal when you react to malicious or defective hardware. + * Also, don't abort when fsync() returned -EINVAL, for older kernels which do + * not implement wdm_flush() will return -EINVAL. + */ +static int wdm_fsync(struct file *file, loff_t start, loff_t end, int datasync) +{ + return wdm_wait_for_response(file, MAX_SCHEDULE_TIMEOUT); +} + +/* + * Same with wdm_fsync(), except it uses finite timeout in order to react to + * malicious or defective hardware which ceased communication after close() was + * implicitly called due to process termination. + */ +static int wdm_flush(struct file *file, fl_owner_t id) +{ + return wdm_wait_for_response(file, WDM_FLUSH_TIMEOUT); } static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait) @@ -694,11 +752,13 @@ static int wdm_release(struct inode *inode, struct file *file) if (!desc->count) { if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n"); - kill_urbs(desc); + poison_urbs(desc); spin_lock_irq(&desc->iuspin); desc->resp_count = 0; + clear_bit(WDM_RESPONDING, &desc->flags); spin_unlock_irq(&desc->iuspin); desc->manage_power(desc->intf, 0); + unpoison_urbs(desc); } else { /* must avoid dev_printk here as desc->intf is invalid */ pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); @@ -729,6 +789,7 @@ static const struct file_operations wdm_fops = { .owner = THIS_MODULE, .read = wdm_read, .write = wdm_write, + .fsync = wdm_fsync, .open = wdm_open, .flush = wdm_flush, .release = wdm_release, @@ -988,7 +1049,7 @@ static void wdm_disconnect(struct usb_interface *intf) wake_up_all(&desc->wait); mutex_lock(&desc->rlock); mutex_lock(&desc->wlock); - kill_urbs(desc); + poison_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); mutex_unlock(&desc->wlock); @@ -1031,9 +1092,10 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message) set_bit(WDM_SUSPENDING, &desc->flags); spin_unlock_irq(&desc->iuspin); /* callback submits work - order is essential */ - kill_urbs(desc); + poison_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); + unpoison_urbs(desc); } if (!PMSG_IS_AUTO(message)) { mutex_unlock(&desc->wlock); @@ -1091,7 +1153,7 @@ static int wdm_pre_reset(struct usb_interface *intf) wake_up_all(&desc->wait); mutex_lock(&desc->rlock); mutex_lock(&desc->wlock); - kill_urbs(desc); + poison_urbs(desc); cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->service_outs_intr); return 0; @@ -1102,6 +1164,7 @@ static int wdm_post_reset(struct usb_interface *intf) struct wdm_device *desc = wdm_find_device(intf); int rv; + unpoison_urbs(desc); clear_bit(WDM_OVERFLOW, &desc->flags); clear_bit(WDM_RESETTING, &desc->flags); rv = recover_from_urb_loss(desc); |