[media] gspca: Switch to V4L2 core locking, except for the buffer queuing ioctls

Due to latency concerns the VIDIOC_QBUF, DQBUF and QUERYBUF do not use the
core lock, instead they rely only on queue_lock.

Changes by HdG:
1) Change release from the video_device to the v4l2_device, to avoid a
race on disconnect.
2) Adjust for the V4L2 core changes which cause non ioctl fops to no longer
take the V4L2 core lock.

[mchehab@redhat.com: fix a merge conflict]
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index a14c8f7..2687e76 100644 (file)
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -850,14 +850,6 @@ static int gspca_init_transfer(struct gspca_dev *gspca_dev)
        struct ep_tb_s ep_tb[MAX_ALT];
        int n, ret, xfer, alt, alt_idx;
 
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
-
-       if (!gspca_dev->present) {
-               ret = -ENODEV;
-               goto unlock;
-       }
-
        /* reset the streaming variables */
        gspca_dev->image = NULL;
        gspca_dev->image_len = 0;
@@ -872,7 +864,7 @@ static int gspca_init_transfer(struct gspca_dev *gspca_dev)
        if (gspca_dev->sd_desc->isoc_init) {
                ret = gspca_dev->sd_desc->isoc_init(gspca_dev);
                if (ret < 0)
-                       goto unlock;
+                       return ret;
        }
        xfer = gspca_dev->cam.bulk ? USB_ENDPOINT_XFER_BULK
                                   : USB_ENDPOINT_XFER_ISOC;
@@ -883,8 +875,7 @@ static int gspca_init_transfer(struct gspca_dev *gspca_dev)
                ep = alt_xfer(&intf->altsetting[gspca_dev->alt], xfer);
                if (ep == NULL) {
                        pr_err("bad altsetting %d\n", gspca_dev->alt);
-                       ret = -EIO;
-                       goto out;
+                       return -EIO;
                }
                ep_tb[0].alt = gspca_dev->alt;
                alt_idx = 1;
@@ -895,8 +886,7 @@ static int gspca_init_transfer(struct gspca_dev *gspca_dev)
                alt_idx = build_isoc_ep_tb(gspca_dev, intf, ep_tb);
                if (alt_idx <= 0) {
                        pr_err("no transfer endpoint found\n");
-                       ret = -EIO;
-                       goto unlock;
+                       return -EIO;
                }
        }
 
@@ -991,8 +981,6 @@ retry:
        }
 out:
        gspca_input_create_urb(gspca_dev);
-unlock:
-       mutex_unlock(&gspca_dev->usb_lock);
        return ret;
 }
 
@@ -1062,7 +1050,6 @@ static int gspca_get_mode(struct gspca_dev *gspca_dev,
 static int vidioc_g_register(struct file *file, void *priv,
                        struct v4l2_dbg_register *reg)
 {
-       int ret;
        struct gspca_dev *gspca_dev = video_drvdata(file);
 
        if (!gspca_dev->sd_desc->get_chip_ident)
@@ -1071,22 +1058,13 @@ static int vidioc_g_register(struct file *file, void *priv,
        if (!gspca_dev->sd_desc->get_register)
                return -ENOTTY;
 
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
        gspca_dev->usb_err = 0;
-       if (gspca_dev->present)
-               ret = gspca_dev->sd_desc->get_register(gspca_dev, reg);
-       else
-               ret = -ENODEV;
-       mutex_unlock(&gspca_dev->usb_lock);
-
-       return ret;
+       return gspca_dev->sd_desc->get_register(gspca_dev, reg);
 }
 
 static int vidioc_s_register(struct file *file, void *priv,
                        struct v4l2_dbg_register *reg)
 {
-       int ret;
        struct gspca_dev *gspca_dev = video_drvdata(file);
 
        if (!gspca_dev->sd_desc->get_chip_ident)
@@ -1095,38 +1073,21 @@ static int vidioc_s_register(struct file *file, void *priv,
        if (!gspca_dev->sd_desc->set_register)
                return -ENOTTY;
 
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
        gspca_dev->usb_err = 0;
-       if (gspca_dev->present)
-               ret = gspca_dev->sd_desc->set_register(gspca_dev, reg);
-       else
-               ret = -ENODEV;
-       mutex_unlock(&gspca_dev->usb_lock);
-
-       return ret;
+       return gspca_dev->sd_desc->set_register(gspca_dev, reg);
 }
 #endif
 
 static int vidioc_g_chip_ident(struct file *file, void *priv,
                        struct v4l2_dbg_chip_ident *chip)
 {
-       int ret;
        struct gspca_dev *gspca_dev = video_drvdata(file);
 
        if (!gspca_dev->sd_desc->get_chip_ident)
                return -ENOTTY;
 
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
        gspca_dev->usb_err = 0;
-       if (gspca_dev->present)
-               ret = gspca_dev->sd_desc->get_chip_ident(gspca_dev, chip);
-       else
-               ret = -ENODEV;
-       mutex_unlock(&gspca_dev->usb_lock);
-
-       return ret;
+       return gspca_dev->sd_desc->get_chip_ident(gspca_dev, chip);
 }
 
 static int vidioc_enum_fmt_vid_cap(struct file *file, void  *priv,
@@ -1321,9 +1282,10 @@ static int vidioc_enum_frameintervals(struct file *filp, void *priv,
        return -EINVAL;
 }
 
-static void gspca_release(struct video_device *vfd)
+static void gspca_release(struct v4l2_device *v4l2_device)
 {
-       struct gspca_dev *gspca_dev = container_of(vfd, struct gspca_dev, vdev);
+       struct gspca_dev *gspca_dev =
+               container_of(v4l2_device, struct gspca_dev, v4l2_dev);
 
        PDEBUG(D_PROBE, "%s released",
                video_device_node_name(&gspca_dev->vdev));
@@ -1339,8 +1301,6 @@ static int dev_open(struct file *file)
        struct gspca_dev *gspca_dev = video_drvdata(file);
 
        PDEBUG(D_STREAM, "[%s] open", current->comm);
-       if (!gspca_dev->present)
-               return -ENODEV;
 
        /* protect the subdriver against rmmod */
        if (!try_module_get(gspca_dev->module))
@@ -1363,21 +1323,27 @@ static int dev_close(struct file *file)
        struct gspca_dev *gspca_dev = video_drvdata(file);
 
        PDEBUG(D_STREAM, "[%s] close", current->comm);
-       if (mutex_lock_interruptible(&gspca_dev->queue_lock))
+
+       /* Needed for gspca_stream_off, always lock before queue_lock! */
+       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
                return -ERESTARTSYS;
 
+       if (mutex_lock_interruptible(&gspca_dev->queue_lock)) {
+               mutex_unlock(&gspca_dev->usb_lock);
+               return -ERESTARTSYS;
+       }
+
        /* if the file did the capture, free the streaming resources */
        if (gspca_dev->capt_file == file) {
                if (gspca_dev->streaming) {
-                       mutex_lock(&gspca_dev->usb_lock);
                        gspca_dev->usb_err = 0;
                        gspca_stream_off(gspca_dev);
-                       mutex_unlock(&gspca_dev->usb_lock);
                }
                frame_free(gspca_dev);
        }
        module_put(gspca_dev->module);
        mutex_unlock(&gspca_dev->queue_lock);
+       mutex_unlock(&gspca_dev->usb_lock);
 
        PDEBUG(D_STREAM, "close done");
 
@@ -1388,15 +1354,7 @@ static int vidioc_querycap(struct file *file, void  *priv,
                           struct v4l2_capability *cap)
 {
        struct gspca_dev *gspca_dev = video_drvdata(file);
-       int ret;
 
-       /* protect the access to the usb device */
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
-       if (!gspca_dev->present) {
-               ret = -ENODEV;
-               goto out;
-       }
        strlcpy((char *) cap->driver, gspca_dev->sd_desc->name,
                        sizeof cap->driver);
        if (gspca_dev->dev->product != NULL) {
@@ -1414,10 +1372,7 @@ static int vidioc_querycap(struct file *file, void  *priv,
                          | V4L2_CAP_STREAMING
                          | V4L2_CAP_READWRITE;
        cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;
-       ret = 0;
-out:
-       mutex_unlock(&gspca_dev->usb_lock);
-       return ret;
+       return 0;
 }
 
 static int get_ctrl(struct gspca_dev *gspca_dev,
@@ -1486,7 +1441,7 @@ static int vidioc_s_ctrl(struct file *file, void *priv,
        struct gspca_dev *gspca_dev = video_drvdata(file);
        const struct ctrl *ctrls;
        struct gspca_ctrl *gspca_ctrl;
-       int idx, ret;
+       int idx;
 
        idx = get_ctrl(gspca_dev, ctrl->id);
        if (idx < 0)
@@ -1506,27 +1461,16 @@ static int vidioc_s_ctrl(struct file *file, void *priv,
                        return -ERANGE;
        }
        PDEBUG(D_CONF, "set ctrl [%08x] = %d", ctrl->id, ctrl->value);
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
-       if (!gspca_dev->present) {
-               ret = -ENODEV;
-               goto out;
-       }
        gspca_dev->usb_err = 0;
-       if (ctrls->set != NULL) {
-               ret = ctrls->set(gspca_dev, ctrl->value);
-               goto out;
-       }
+       if (ctrls->set != NULL)
+               return ctrls->set(gspca_dev, ctrl->value);
        if (gspca_ctrl != NULL) {
                gspca_ctrl->val = ctrl->value;
                if (ctrls->set_control != NULL
                 && gspca_dev->streaming)
                        ctrls->set_control(gspca_dev);
        }
-       ret = gspca_dev->usb_err;
-out:
-       mutex_unlock(&gspca_dev->usb_lock);
-       return ret;
+       return gspca_dev->usb_err;
 }
 
 static int vidioc_g_ctrl(struct file *file, void *priv,
@@ -1534,30 +1478,19 @@ static int vidioc_g_ctrl(struct file *file, void *priv,
 {
        struct gspca_dev *gspca_dev = video_drvdata(file);
        const struct ctrl *ctrls;
-       int idx, ret;
+       int idx;
 
        idx = get_ctrl(gspca_dev, ctrl->id);
        if (idx < 0)
                return -EINVAL;
        ctrls = &gspca_dev->sd_desc->ctrls[idx];
 
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
-       if (!gspca_dev->present) {
-               ret = -ENODEV;
-               goto out;
-       }
        gspca_dev->usb_err = 0;
-       if (ctrls->get != NULL) {
-               ret = ctrls->get(gspca_dev, &ctrl->value);
-               goto out;
-       }
+       if (ctrls->get != NULL)
+               return ctrls->get(gspca_dev, &ctrl->value);
        if (gspca_dev->cam.ctrls != NULL)
                ctrl->value = gspca_dev->cam.ctrls[idx].val;
-       ret = 0;
-out:
-       mutex_unlock(&gspca_dev->usb_lock);
-       return ret;
+       return 0;
 }
 
 static int vidioc_querymenu(struct file *file, void *priv,
@@ -1640,10 +1573,8 @@ static int vidioc_reqbufs(struct file *file, void *priv,
        /* stop streaming */
        streaming = gspca_dev->streaming;
        if (streaming) {
-               mutex_lock(&gspca_dev->usb_lock);
                gspca_dev->usb_err = 0;
                gspca_stream_off(gspca_dev);
-               mutex_unlock(&gspca_dev->usb_lock);
 
                /* Don't restart the stream when switching from read
                 * to mmap mode */
@@ -1748,13 +1679,8 @@ static int vidioc_streamoff(struct file *file, void *priv,
        }
 
        /* stop streaming */
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock)) {
-               ret = -ERESTARTSYS;
-               goto out;
-       }
        gspca_dev->usb_err = 0;
        gspca_stream_off(gspca_dev);
-       mutex_unlock(&gspca_dev->usb_lock);
        /* In case another thread is waiting in dqbuf */
        wake_up_interruptible(&gspca_dev->wq);
 
@@ -1772,38 +1698,22 @@ static int vidioc_g_jpegcomp(struct file *file, void *priv,
                        struct v4l2_jpegcompression *jpegcomp)
 {
        struct gspca_dev *gspca_dev = video_drvdata(file);
-       int ret;
 
        if (!gspca_dev->sd_desc->get_jcomp)
                return -ENOTTY;
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
        gspca_dev->usb_err = 0;
-       if (gspca_dev->present)
-               ret = gspca_dev->sd_desc->get_jcomp(gspca_dev, jpegcomp);
-       else
-               ret = -ENODEV;
-       mutex_unlock(&gspca_dev->usb_lock);
-       return ret;
+       return gspca_dev->sd_desc->get_jcomp(gspca_dev, jpegcomp);
 }
 
 static int vidioc_s_jpegcomp(struct file *file, void *priv,
                        struct v4l2_jpegcompression *jpegcomp)
 {
        struct gspca_dev *gspca_dev = video_drvdata(file);
-       int ret;
 
        if (!gspca_dev->sd_desc->set_jcomp)
                return -ENOTTY;
-       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-               return -ERESTARTSYS;
        gspca_dev->usb_err = 0;
-       if (gspca_dev->present)
-               ret = gspca_dev->sd_desc->set_jcomp(gspca_dev, jpegcomp);
-       else
-               ret = -ENODEV;
-       mutex_unlock(&gspca_dev->usb_lock);
-       return ret;
+       return gspca_dev->sd_desc->set_jcomp(gspca_dev, jpegcomp);
 }
 
 static int vidioc_g_parm(struct file *filp, void *priv,
@@ -1814,21 +1724,10 @@ static int vidioc_g_parm(struct file *filp, void *priv,
        parm->parm.capture.readbuffers = gspca_dev->nbufread;
 
        if (gspca_dev->sd_desc->get_streamparm) {
-               int ret;
-
-               if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-                       return -ERESTARTSYS;
-               if (gspca_dev->present) {
-                       gspca_dev->usb_err = 0;
-                       gspca_dev->sd_desc->get_streamparm(gspca_dev, parm);
-                       ret = gspca_dev->usb_err;
-               } else {
-                       ret = -ENODEV;
-               }
-               mutex_unlock(&gspca_dev->usb_lock);
-               return ret;
+               gspca_dev->usb_err = 0;
+               gspca_dev->sd_desc->get_streamparm(gspca_dev, parm);
+               return gspca_dev->usb_err;
        }
-
        return 0;
 }
 
@@ -1845,19 +1744,9 @@ static int vidioc_s_parm(struct file *filp, void *priv,
                gspca_dev->nbufread = n;
 
        if (gspca_dev->sd_desc->set_streamparm) {
-               int ret;
-
-               if (mutex_lock_interruptible(&gspca_dev->usb_lock))
-                       return -ERESTARTSYS;
-               if (gspca_dev->present) {
-                       gspca_dev->usb_err = 0;
-                       gspca_dev->sd_desc->set_streamparm(gspca_dev, parm);
-                       ret = gspca_dev->usb_err;
-               } else {
-                       ret = -ENODEV;
-               }
-               mutex_unlock(&gspca_dev->usb_lock);
-               return ret;
+               gspca_dev->usb_err = 0;
+               gspca_dev->sd_desc->set_streamparm(gspca_dev, parm);
+               return gspca_dev->usb_err;
        }
 
        return 0;
@@ -1877,10 +1766,6 @@ static int dev_mmap(struct file *file, struct vm_area_struct *vma)
 
        if (mutex_lock_interruptible(&gspca_dev->queue_lock))
                return -ERESTARTSYS;
-       if (!gspca_dev->present) {
-               ret = -ENODEV;
-               goto out;
-       }
        if (gspca_dev->capt_file != file) {
                ret = -EINVAL;
                goto out;
@@ -2008,14 +1893,6 @@ static int vidioc_dqbuf(struct file *file, void *priv,
 
        gspca_dev->fr_o = (i + 1) % GSPCA_MAX_FRAMES;
 
-       if (gspca_dev->sd_desc->dq_callback) {
-               mutex_lock(&gspca_dev->usb_lock);
-               gspca_dev->usb_err = 0;
-               if (gspca_dev->present)
-                       gspca_dev->sd_desc->dq_callback(gspca_dev);
-               mutex_unlock(&gspca_dev->usb_lock);
-       }
-
        frame->v4l2_buf.flags &= ~V4L2_BUF_FLAG_DONE;
        memcpy(v4l2_buf, &frame->v4l2_buf, sizeof *v4l2_buf);
        PDEBUG(D_FRAM, "dqbuf %d", j);
@@ -2032,6 +1909,15 @@ static int vidioc_dqbuf(struct file *file, void *priv,
        }
 out:
        mutex_unlock(&gspca_dev->queue_lock);
+
+       if (ret == 0 && gspca_dev->sd_desc->dq_callback) {
+               mutex_lock(&gspca_dev->usb_lock);
+               gspca_dev->usb_err = 0;
+               if (gspca_dev->present)
+                       gspca_dev->sd_desc->dq_callback(gspca_dev);
+               mutex_unlock(&gspca_dev->usb_lock);
+       }
+
        return ret;
 }
 
@@ -2103,6 +1989,10 @@ static int read_alloc(struct gspca_dev *gspca_dev,
        int i, ret;
 
        PDEBUG(D_STREAM, "read alloc");
+
+       if (mutex_lock_interruptible(&gspca_dev->usb_lock))
+               return -ERESTARTSYS;
+
        if (gspca_dev->nframes == 0) {
                struct v4l2_requestbuffers rb;
 
@@ -2113,7 +2003,7 @@ static int read_alloc(struct gspca_dev *gspca_dev,
                ret = vidioc_reqbufs(file, gspca_dev, &rb);
                if (ret != 0) {
                        PDEBUG(D_STREAM, "read reqbuf err %d", ret);
-                       return ret;
+                       goto out;
                }
                memset(&v4l2_buf, 0, sizeof v4l2_buf);
                v4l2_buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
@@ -2123,16 +2013,17 @@ static int read_alloc(struct gspca_dev *gspca_dev,
                        ret = vidioc_qbuf(file, gspca_dev, &v4l2_buf);
                        if (ret != 0) {
                                PDEBUG(D_STREAM, "read qbuf err: %d", ret);
-                               return ret;
+                               goto out;
                        }
                }
-               gspca_dev->memory = GSPCA_MEMORY_READ;
        }
 
        /* start streaming */
        ret = vidioc_streamon(file, gspca_dev, V4L2_BUF_TYPE_VIDEO_CAPTURE);
        if (ret != 0)
                PDEBUG(D_STREAM, "read streamon err %d", ret);
+out:
+       mutex_unlock(&gspca_dev->usb_lock);
        return ret;
 }
 
@@ -2177,8 +2068,6 @@ static ssize_t dev_read(struct file *file, char __user *data,
        int n, ret, ret2;
 
        PDEBUG(D_FRAM, "read (%zd)", count);
-       if (!gspca_dev->present)
-               return -ENODEV;
        if (gspca_dev->memory == GSPCA_MEMORY_NO) { /* first time ? */
                ret = read_alloc(gspca_dev, file);
                if (ret != 0)
@@ -2280,7 +2169,7 @@ static const struct video_device gspca_template = {
        .name = "gspca main driver",
        .fops = &dev_fops,
        .ioctl_ops = &dev_ioctl_ops,
-       .release = gspca_release,
+       .release = video_device_release_empty, /* We use v4l2_dev.release */
 };
 
 /* initialize the controls */
@@ -2352,6 +2241,7 @@ int gspca_dev_probe2(struct usb_interface *intf,
                }
        }
 
+       gspca_dev->v4l2_dev.release = gspca_release;
        ret = v4l2_device_register(&intf->dev, &gspca_dev->v4l2_dev);
        if (ret)
                goto out;
@@ -2366,6 +2256,7 @@ int gspca_dev_probe2(struct usb_interface *intf,
        gspca_dev->present = 1;
 
        mutex_init(&gspca_dev->usb_lock);
+       gspca_dev->vdev.lock = &gspca_dev->usb_lock;
        mutex_init(&gspca_dev->queue_lock);
        init_waitqueue_head(&gspca_dev->wq);
 
@@ -2388,6 +2279,15 @@ int gspca_dev_probe2(struct usb_interface *intf,
        if (ret)
                goto out;
 
+       /*
+        * Don't take usb_lock for these ioctls. This improves latency if
+        * usb_lock is taken for a long time, e.g. when changing a control
+        * value, and a new frame is ready to be dequeued.
+        */
+       v4l2_dont_use_lock(&gspca_dev->vdev, VIDIOC_DQBUF);
+       v4l2_dont_use_lock(&gspca_dev->vdev, VIDIOC_QBUF);
+       v4l2_dont_use_lock(&gspca_dev->vdev, VIDIOC_QUERYBUF);
+
        /* init video stuff */
        ret = video_register_device(&gspca_dev->vdev,
                                  VFL_TYPE_GRABBER,
@@ -2455,11 +2355,13 @@ void gspca_disconnect(struct usb_interface *intf)
 
        PDEBUG(D_PROBE, "%s disconnect",
                video_device_node_name(&gspca_dev->vdev));
+
        mutex_lock(&gspca_dev->usb_lock);
 
+       usb_set_intfdata(intf, NULL);
+       gspca_dev->dev = NULL;
        gspca_dev->present = 0;
        wake_up_interruptible(&gspca_dev->wq);
-
        destroy_urbs(gspca_dev);
 
 #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
@@ -2471,18 +2373,13 @@ void gspca_disconnect(struct usb_interface *intf)
        }
 #endif
 
-       /* the device is freed at exit of this function */
-       gspca_dev->dev = NULL;
        v4l2_device_disconnect(&gspca_dev->v4l2_dev);
-       mutex_unlock(&gspca_dev->usb_lock);
+       video_unregister_device(&gspca_dev->vdev);
 
-       usb_set_intfdata(intf, NULL);
+       mutex_unlock(&gspca_dev->usb_lock);
 
-       /* release the device */
        /* (this will call gspca_release() immediately or on last close) */
-       video_unregister_device(&gspca_dev->vdev);
-
-/*     PDEBUG(D_PROBE, "disconnect complete"); */
+       v4l2_device_put(&gspca_dev->v4l2_dev);
 }
 EXPORT_SYMBOL(gspca_disconnect);
 
@@ -2493,17 +2390,16 @@ int gspca_suspend(struct usb_interface *intf, pm_message_t message)
 
        if (!gspca_dev->streaming)
                return 0;
+       mutex_lock(&gspca_dev->usb_lock);
        gspca_dev->frozen = 1;          /* avoid urb error messages */
        if (gspca_dev->sd_desc->stopN)
                gspca_dev->sd_desc->stopN(gspca_dev);
        destroy_urbs(gspca_dev);
        gspca_input_destroy_urb(gspca_dev);
        gspca_set_alt0(gspca_dev);
-       if (gspca_dev->sd_desc->stop0) {
-               mutex_lock(&gspca_dev->usb_lock);
+       if (gspca_dev->sd_desc->stop0)
                gspca_dev->sd_desc->stop0(gspca_dev);
-               mutex_unlock(&gspca_dev->usb_lock);
-       }
+       mutex_unlock(&gspca_dev->usb_lock);
        return 0;
 }
 EXPORT_SYMBOL(gspca_suspend);
@@ -2513,6 +2409,7 @@ int gspca_resume(struct usb_interface *intf)
        struct gspca_dev *gspca_dev = usb_get_intfdata(intf);
        int streaming, ret = 0;
 
+       mutex_lock(&gspca_dev->usb_lock);
        gspca_dev->frozen = 0;
        gspca_dev->sd_desc->init(gspca_dev);
        gspca_input_create_urb(gspca_dev);
@@ -2524,11 +2421,9 @@ int gspca_resume(struct usb_interface *intf)
        streaming = gspca_dev->streaming;
        gspca_dev->streaming = 0;
        v4l2_ctrl_handler_setup(gspca_dev->vdev.ctrl_handler);
-       if (streaming) {
-               mutex_lock(&gspca_dev->queue_lock);
+       if (streaming)
                ret = gspca_init_transfer(gspca_dev);
-               mutex_unlock(&gspca_dev->queue_lock);
-       }
+       mutex_unlock(&gspca_dev->usb_lock);
        return ret;
 }
 EXPORT_SYMBOL(gspca_resume);

diff --git a/drivers/media/video/gspca/gspca.h b/drivers/media/video/gspca/gspca.h
index c1ebf7c..436d881 100644 (file)
--- a/drivers/media/video/gspca/gspca.h
+++ b/drivers/media/video/gspca/gspca.h
@@ -163,6 +163,7 @@ struct gspca_dev {
        struct v4l2_device v4l2_dev;
        struct usb_device *dev;
        struct file *capt_file;         /* file doing video capture */
+                                       /* protected by queue_lock */
 #if defined(CONFIG_INPUT) || defined(CONFIG_INPUT_MODULE)
        struct input_dev *input_dev;
        char phys[64];                  /* physical device path */
@@ -192,7 +193,7 @@ struct gspca_dev {
        u8 fr_o;                                /* next frame to dequeue */
        __u8 last_packet_type;
        __s8 empty_packet;              /* if (-1) don't check empty packets */
-       __u8 streaming;
+       __u8 streaming;                 /* protected by both mutexes (*) */
 
        __u8 curr_mode;                 /* current camera mode */
        __u32 pixfmt;                   /* current mode parameters */
@@ -214,6 +215,10 @@ struct gspca_dev {
        __u8 iface;                     /* USB interface number */
        __u8 alt;                       /* USB alternate setting */
        u8 audio;                       /* presence of audio device */
+
+       /* (*) These variables are proteced by both usb_lock and queue_lock,
+          that is any code setting them is holding *both*, which means that
+          any code getting them needs to hold at least one of them */
 };
 
 int gspca_dev_probe(struct usb_interface *intf,