1 files changed, 46 insertions, 40 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 0725b1871f23..efc4373ededb 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -51,6 +51,7 @@
  */
 
 #undef DEBUG
+#undef VERBOSE_DEBUG
 
 #include <linux/kernel.h>
 #include <linux/errno.h>
@@ -70,6 +71,9 @@
 
 #include "cdc-acm.h"
 
+
+#define ACM_CLOSE_TIMEOUT       15      /* seconds to let writes drain */
+
 /*
  * Version Information
  */
@@ -85,6 +89,12 @@ static DEFINE_MUTEX(open_mutex);
 
 #define ACM_READY(acm)  (acm && acm->dev && acm->used)
 
+#ifdef VERBOSE_DEBUG
+#define verbose 1
+#else
+#define verbose 0
+#endif
+
 /*
  * Functions for ACM control messages.
  */
@@ -136,19 +146,17 @@ static int acm_wb_alloc(struct acm *acm)
 static int acm_wb_is_avail(struct acm *acm)
 {
         int i, n;
+        unsigned long flags;
 
         n = ACM_NW;
+        spin_lock_irqsave(&acm->write_lock, flags);
         for (i = 0; i < ACM_NW; i++) {
                 n -= acm->wb[i].use;
         }
+        spin_unlock_irqrestore(&acm->write_lock, flags);
         return n;
 }
 
-static inline int acm_wb_is_used(struct acm *acm, int wbn)
-{
-        return acm->wb[wbn].use;
-}
-
 /*
  * Finish write.
  */
@@ -157,7 +165,6 @@ static void acm_write_done(struct acm *acm, struct acm_wb *wb)
         unsigned long flags;
 
         spin_lock_irqsave(&acm->write_lock, flags);
-        acm->write_ready = 1;
         wb->use = 0;
         acm->transmitting--;
         spin_unlock_irqrestore(&acm->write_lock, flags);
@@ -190,40 +197,25 @@ static int acm_start_wb(struct acm *acm, struct acm_wb *wb)
 static int acm_write_start(struct acm *acm, int wbn)
 {
         unsigned long flags;
-        struct acm_wb *wb;
+        struct acm_wb *wb = &acm->wb[wbn];
         int rc;
 
         spin_lock_irqsave(&acm->write_lock, flags);
         if (!acm->dev) {
+                wb->use = 0;
                 spin_unlock_irqrestore(&acm->write_lock, flags);
                 return -ENODEV;
         }
 
-        if (!acm->write_ready) {
-                spin_unlock_irqrestore(&acm->write_lock, flags);
-                return 0;       /* A white lie */
-        }
-
-        wb = &acm->wb[wbn];
-        if(acm_wb_is_avail(acm) <= 1)
-                acm->write_ready = 0;
-
         dbg("%s susp_count: %d", __func__, acm->susp_count);
         if (acm->susp_count) {
-                acm->old_ready = acm->write_ready;
                 acm->delayed_wb = wb;
-                acm->write_ready = 0;
                 schedule_work(&acm->waker);
                 spin_unlock_irqrestore(&acm->write_lock, flags);
                 return 0;       /* A white lie */
         }
         usb_mark_last_busy(acm->dev);
 
-        if (!acm_wb_is_used(acm, wbn)) {
-                spin_unlock_irqrestore(&acm->write_lock, flags);
-                return 0;
-        }
-
         rc = acm_start_wb(acm, wb);
         spin_unlock_irqrestore(&acm->write_lock, flags);
 
@@ -488,22 +480,28 @@ urbs:
 /* data interface wrote those outgoing bytes */
 static void acm_write_bulk(struct urb *urb)
 {
-        struct acm *acm;
         struct acm_wb *wb = urb->context;
+        struct acm *acm = wb->instance;
 
-        dbg("Entering acm_write_bulk with status %d", urb->status);
+        if (verbose || urb->status
+                        || (urb->actual_length != urb->transfer_buffer_length))
+                dev_dbg(&acm->data->dev, "tx %d/%d bytes -- > %d\n",
+                        urb->actual_length,
+                        urb->transfer_buffer_length,
+                        urb->status);
 
-        acm = wb->instance;
         acm_write_done(acm, wb);
         if (ACM_READY(acm))
                 schedule_work(&acm->work);
+        else
+                wake_up_interruptible(&acm->drain_wait);
 }
 
 static void acm_softint(struct work_struct *work)
 {
         struct acm *acm = container_of(work, struct acm, work);
-        dbg("Entering acm_softint.");
-        
+
+        dev_vdbg(&acm->data->dev, "tx work\n");
         if (!ACM_READY(acm))
                 return;
         tty_wakeup(acm->tty);
@@ -512,7 +510,6 @@ static void acm_softint(struct work_struct *work)
 static void acm_waker(struct work_struct *waker)
 {
         struct acm *acm = container_of(waker, struct acm, waker);
-        long flags;
         int rv;
 
         rv = usb_autopm_get_interface(acm->control);
@@ -524,9 +521,6 @@ static void acm_waker(struct work_struct *waker)
                 acm_start_wb(acm, acm->delayed_wb);
                 acm->delayed_wb = NULL;
         }
-        spin_lock_irqsave(&acm->write_lock, flags);
-        acm->write_ready = acm->old_ready;
-        spin_unlock_irqrestore(&acm->write_lock, flags);
         usb_autopm_put_interface(acm->control);
 }
 
@@ -628,6 +622,8 @@ static void acm_tty_unregister(struct acm *acm)
         kfree(acm);
 }
 
+static int acm_tty_chars_in_buffer(struct tty_struct *tty);
+
 static void acm_tty_close(struct tty_struct *tty, struct file *filp)
 {
         struct acm *acm = tty->driver_data;
@@ -642,6 +638,13 @@ static void acm_tty_close(struct tty_struct *tty, struct file *filp)
                 if (acm->dev) {
                         usb_autopm_get_interface(acm->control);
                         acm_set_control(acm, acm->ctrlout = 0);
+
+                        /* try letting the last writes drain naturally */
+                        wait_event_interruptible_timeout(acm->drain_wait,
+                                        (ACM_NW == acm_wb_is_avail(acm))
+                                                || !acm->dev,
+                                        ACM_CLOSE_TIMEOUT * HZ);
+
                         usb_kill_urb(acm->ctrlurb);
                         for (i = 0; i < ACM_NW; i++)
                                 usb_kill_urb(acm->wb[i].urb);
@@ -697,7 +700,7 @@ static int acm_tty_write_room(struct tty_struct *tty)
          * Do not let the line discipline to know that we have a reserve,
          * or it might get too enthusiastic.
          */
-        return (acm->write_ready && acm_wb_is_avail(acm)) ? acm->writesize : 0;
+        return acm_wb_is_avail(acm) ? acm->writesize : 0;
 }
 
 static int acm_tty_chars_in_buffer(struct tty_struct *tty)
@@ -1072,11 +1075,11 @@ skip_normal_probe:
         acm->urb_task.data = (unsigned long) acm;
         INIT_WORK(&acm->work, acm_softint);
         INIT_WORK(&acm->waker, acm_waker);
+        init_waitqueue_head(&acm->drain_wait);
         spin_lock_init(&acm->throttle_lock);
         spin_lock_init(&acm->write_lock);
         spin_lock_init(&acm->read_lock);
         mutex_init(&acm->mutex);
-        acm->write_ready = 1;
         acm->rx_endpoint = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
 
         buf = usb_buffer_alloc(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
@@ -1108,9 +1111,11 @@ skip_normal_probe:
                 rcv->instance = acm;
         }
         for (i = 0; i < num_rx_buf; i++) {
-                struct acm_rb *buf = &(acm->rb[i]);
+                struct acm_rb *rb = &(acm->rb[i]);
 
-                if (!(buf->base = usb_buffer_alloc(acm->dev, readsize, GFP_KERNEL, &buf->dma))) {
+                rb->base = usb_buffer_alloc(acm->dev, readsize,
+                                GFP_KERNEL, &rb->dma);
+                if (!rb->base) {
                         dev_dbg(&intf->dev, "out of memory (read bufs usb_buffer_alloc)\n");
                         goto alloc_fail7;
                 }
@@ -1172,6 +1177,7 @@ skip_countries:
         acm_set_line(acm, &acm->line);
 
         usb_driver_claim_interface(&acm_driver, data_interface, acm);
+        usb_set_intfdata(data_interface, acm);
 
         usb_get_intf(control_interface);
         tty_register_device(acm_tty_driver, minor, &control_interface->dev);
@@ -1221,11 +1227,11 @@ static void acm_disconnect(struct usb_interface *intf)
         struct acm *acm = usb_get_intfdata(intf);
         struct usb_device *usb_dev = interface_to_usbdev(intf);
 
-        mutex_lock(&open_mutex);
-        if (!acm || !acm->dev) {
-                mutex_unlock(&open_mutex);
+        /* sibling interface is already cleaning up */
+        if (!acm)
                 return;
-        }
+
+        mutex_lock(&open_mutex);
         if (acm->country_codes){
                 device_remove_file(&acm->control->dev,
                                 &dev_attr_wCountryCodes);