[media] staging: easycap: Split device struct alloc and retrieval code

When the device is probed a driver struct is either
allocated or retrieved.
This operation is logically splitted in several functions.
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/staging/media/easycap/easycap_main.c

@@ -2842,87 +2842,92 @@ static void easycap_complete(struct urb *purb)
 	return;
 }
 
-static const struct v4l2_file_operations v4l2_fops = {
-	.owner		= THIS_MODULE,
-	.open		= easycap_open_noinode,
-	.unlocked_ioctl	= easycap_unlocked_ioctl,
-	.poll		= easycap_poll,
-	.mmap		= easycap_mmap,
-};
-
-/*
- * When the device is plugged, this function is called three times,
- * one for each interface.
- */
-static int easycap_usb_probe(struct usb_interface *intf,
-			    const struct usb_device_id *id)
+static struct easycap *alloc_easycap(u8 bInterfaceNumber)
 {
-	struct usb_device *usbdev;
-	struct usb_host_interface *alt;
-	struct usb_endpoint_descriptor *ep;
-	struct usb_interface_descriptor *interface;
-	struct urb *purb;
 	struct easycap *peasycap;
-	int ndong;
-	struct data_urb *pdata_urb;
-	int i, j, k, m, rc;
-	u8 bInterfaceNumber;
-	u8 bInterfaceClass;
-	u8 bInterfaceSubClass;
-	void *pbuf;
-	int okalt[8], isokalt;
-	int okepn[8];
-	int okmps[8];
-	int maxpacketsize;
-	u16 mask;
-	s32 value;
-	struct easycap_format *peasycap_format;
-	int fmtidx;
-	struct inputset *inputset;
+	int i;
 
-	usbdev = interface_to_usbdev(intf);
+	peasycap = kzalloc(sizeof(struct easycap), GFP_KERNEL);
+	if (!peasycap) {
+		SAY("ERROR: Could not allocate peasycap\n");
+		return NULL;
+	}
 
-	alt = usb_altnum_to_altsetting(intf, 0);
-	if (!alt) {
-		SAY("ERROR: usb_host_interface not found\n");
-		return -EFAULT;
+	if (mutex_lock_interruptible(&mutex_dongle)) {
+		SAY("ERROR: cannot lock mutex_dongle\n");
+		kfree(peasycap);
+		return NULL;
 	}
 
-	interface = &alt->desc;
-	if (!interface) {
-		SAY("ERROR: intf_descriptor is NULL\n");
-		return -EFAULT;
+	/* Find a free dongle in easycapdc60_dongle array */
+	for (i = 0; i < DONGLE_MANY; i++) {
+
+		if ((!easycapdc60_dongle[i].peasycap) &&
+		    (!mutex_is_locked(&easycapdc60_dongle[i].mutex_video)) &&
+		    (!mutex_is_locked(&easycapdc60_dongle[i].mutex_audio))) {
+
+			easycapdc60_dongle[i].peasycap = peasycap;
+			peasycap->isdongle = i;
+			JOM(8, "intf[%i]: peasycap-->easycap"
+				"_dongle[%i].peasycap\n",
+				bInterfaceNumber, i);
+			break;
+		}
 	}
 
-	/* Get properties of probed interface */
-	bInterfaceNumber = interface->bInterfaceNumber;
-	bInterfaceClass = interface->bInterfaceClass;
-	bInterfaceSubClass = interface->bInterfaceSubClass;
+	mutex_unlock(&mutex_dongle);
 
-	JOT(4, "intf[%i]: num_altsetting=%i\n",
-			bInterfaceNumber, intf->num_altsetting);
-	JOT(4, "intf[%i]: cur_altsetting - altsetting=%li\n",
-		bInterfaceNumber,
-		(long int)(intf->cur_altsetting - intf->altsetting));
-	JOT(4, "intf[%i]: bInterfaceClass=0x%02X bInterfaceSubClass=0x%02X\n",
-			bInterfaceNumber, bInterfaceClass, bInterfaceSubClass);
+	if (i >= DONGLE_MANY) {
+		SAM("ERROR: too many dongles\n");
+		kfree(peasycap);
+		return NULL;
+	}
 
-	/*
-	 * A new struct easycap is always allocated when interface 0 is probed.
-	 * It is not possible here to free any existing struct easycap.
-	 * This should have been done by easycap_delete() when the device was
-	 * physically unplugged.
-	 * The allocated struct easycap is saved for later usage when
-	 * interfaces 1 and 2 are probed.
+	return peasycap;
+}
+
+/*
+ * FIXME: Identify the appropriate pointer peasycap for interfaces
+ * 1 and 2. The address of peasycap->pusb_device is reluctantly used
+ * for this purpose.
  */
-	if (0 == bInterfaceNumber) {
-		peasycap = kzalloc(sizeof(struct easycap), GFP_KERNEL);
+static struct easycap *get_easycap(struct usb_device *usbdev,
+				   u8 bInterfaceNumber)
+{
+	int i;
+	struct easycap *peasycap;
+
+	for (i = 0; i < DONGLE_MANY; i++) {
+		if (easycapdc60_dongle[i].peasycap->pusb_device == usbdev) {
+			peasycap = easycapdc60_dongle[i].peasycap;
+			JOT(8, "intf[%i]: dongle[%i].peasycap\n",
+					bInterfaceNumber, i);
+			break;
+		}
+	}
+	if (i >= DONGLE_MANY) {
+		SAY("ERROR: peasycap is unknown when probing interface %i\n",
+			bInterfaceNumber);
+		return NULL;
+	}
 	if (!peasycap) {
-			SAY("ERROR: Could not allocate peasycap\n");
-			return -ENOMEM;
+		SAY("ERROR: peasycap is NULL when probing interface %i\n",
+			bInterfaceNumber);
+		return NULL;
 	}
 
-		/* Perform urgent initializations */
+	return peasycap;
+}
+
+static void init_easycap(struct easycap *peasycap,
+			 struct usb_device *usbdev,
+			 struct usb_interface *intf,
+			 u8 bInterfaceNumber)
+{
+	/* Save usb_device and usb_interface */
+	peasycap->pusb_device = usbdev;
+	peasycap->pusb_interface = intf;
+
 	peasycap->minor = -1;
 	kref_init(&peasycap->kref);
 	JOM(8, "intf[%i]: after kref_init(..._video) "
@@ -2936,39 +2941,8 @@ static int easycap_usb_probe(struct usb_interface *intf,
 	init_waitqueue_head(&peasycap->wq_audio);
 	init_waitqueue_head(&peasycap->wq_trigger);
 
-		if (mutex_lock_interruptible(&mutex_dongle)) {
-			SAY("ERROR: cannot down mutex_dongle\n");
-			return -ERESTARTSYS;
-		}
-
-		for (ndong = 0; ndong < DONGLE_MANY; ndong++) {
-			if ((!easycapdc60_dongle[ndong].peasycap) &&
-					(!mutex_is_locked(&easycapdc60_dongle
-						[ndong].mutex_video)) &&
-					(!mutex_is_locked(&easycapdc60_dongle
-						[ndong].mutex_audio))) {
-				easycapdc60_dongle[ndong].peasycap = peasycap;
-				peasycap->isdongle = ndong;
-				JOM(8, "intf[%i]: peasycap-->easycap"
-						"_dongle[%i].peasycap\n",
-						bInterfaceNumber, ndong);
-				break;
-			}
-		}
-
-		if (DONGLE_MANY <= ndong) {
-			SAM("ERROR: too many dongles\n");
-			mutex_unlock(&mutex_dongle);
-			return -ENOMEM;
-		}
-		mutex_unlock(&mutex_dongle);
-
 	peasycap->allocation_video_struct = sizeof(struct easycap);
 
-		/* and further initialize the structure */
-		peasycap->pusb_device = usbdev;
-		peasycap->pusb_interface = intf;
-
 	peasycap->microphone = false;
 
 	peasycap->video_interface = -1;
@@ -2986,44 +2960,45 @@ static int easycap_usb_probe(struct usb_interface *intf,
 	peasycap->audio_isoc_buffer_size = -1;
 
 	peasycap->frame_buffer_many = FRAME_BUFFER_MANY;
+}
 
-		/* Dynamically fill in the available formats */
-		rc = easycap_video_fillin_formats();
-		if (0 > rc) {
-			SAM("ERROR: fillin_formats() rc = %i\n", rc);
-			return -EFAULT;
-		}
-		JOM(4, "%i formats available\n", rc);
+static int populate_inputset(struct easycap *peasycap)
+{
+	struct inputset *inputset;
+	struct easycap_format *peasycap_format;
+	struct v4l2_pix_format *pix;
+	int m, i, k, mask, fmtidx;
+	s32 value;
 
-		/* Populate easycap.inputset[] */
 	inputset = peasycap->inputset;
+
+	/* FIXME: peasycap->ntsc is not yet initialized */
 	fmtidx = peasycap->ntsc ? NTSC_M : PAL_BGHIN;
+
 	m = 0;
 	mask = 0;
-		for (i = 0; 0xFFFF != easycap_standard[i].mask; i++) {
+	for (i = 0; easycap_standard[i].mask != 0xffff; i++) {
 		if (fmtidx == easycap_standard[i].v4l2_standard.index) {
 			m++;
 			for (k = 0; k < INPUT_MANY; k++)
 				inputset[k].standard_offset = i;
-
 			mask = easycap_standard[i].mask;
 		}
 	}
-		if (1 != m) {
-			SAM("ERROR: "
-			    "inputset->standard_offset unpopulated, %i=m\n", m);
+
+	if (m != 1) {
+		SAM("ERROR: inputset->standard_offset unpopulated, %i=m\n", m);
 		return -ENOENT;
 	}
 
 	peasycap_format = &easycap_format[0];
 	m = 0;
 	for (i = 0; peasycap_format->v4l2_format.fmt.pix.width; i++) {
-			struct v4l2_pix_format *pix =
-				&peasycap_format->v4l2_format.fmt.pix;
-			if (((peasycap_format->mask & 0x0F) == (mask & 0x0F)) &&
-			    pix->field == V4L2_FIELD_NONE &&
-			    pix->pixelformat == V4L2_PIX_FMT_UYVY &&
-			    pix->width  == 640 && pix->height == 480) {
+		pix = &peasycap_format->v4l2_format.fmt.pix;
+		if (((peasycap_format->mask & 0x0F) == (mask & 0x0F))
+			&& pix->field == V4L2_FIELD_NONE
+			&& pix->pixelformat == V4L2_PIX_FMT_UYVY
+			&& pix->width  == 640 && pix->height == 480) {
 			m++;
 			for (k = 0; k < INPUT_MANY; k++)
 				inputset[k].format_offset = i;
@@ -3031,13 +3006,13 @@ static int easycap_usb_probe(struct usb_interface *intf,
 		}
 		peasycap_format++;
 	}
-		if (1 != m) {
+	if (m != 1) {
 		SAM("ERROR: inputset[]->format_offset unpopulated\n");
 		return -ENOENT;
 	}
 
 	m = 0;
-		for (i = 0; 0xFFFFFFFF != easycap_control[i].id; i++) {
+	for (i = 0; easycap_control[i].id != 0xffffffff; i++) {
 		value = easycap_control[i].default_value;
 		if (V4L2_CID_BRIGHTNESS == easycap_control[i].id) {
 			m++;
@@ -3058,42 +3033,115 @@ static int easycap_usb_probe(struct usb_interface *intf,
 		}
 	}
 
-		if (4 != m) {
+	if (m != 4) {
 		SAM("ERROR: inputset[]->brightness underpopulated\n");
 		return -ENOENT;
 	}
+
 	for (k = 0; k < INPUT_MANY; k++)
 		inputset[k].input = k;
 	JOM(4, "populated inputset[]\n");
-		JOM(4, "finished initialization\n");
-	} else {
 
-		/*
-		 * FIXME: Identify the appropriate pointer
-		 * peasycap for interfaces 1 and 2.
-		 * The address of peasycap->pusb_device
-		 * is reluctantly used for this purpose.
+	return 0;
+}
+
+static const struct v4l2_file_operations v4l2_fops = {
+	.owner		= THIS_MODULE,
+	.open		= easycap_open_noinode,
+	.unlocked_ioctl	= easycap_unlocked_ioctl,
+	.poll		= easycap_poll,
+	.mmap		= easycap_mmap,
+};
+
+/*
+ * When the device is plugged, this function is called three times,
+ * one for each interface.
  */
-		for (ndong = 0; ndong < DONGLE_MANY; ndong++) {
-			if (usbdev == easycapdc60_dongle[ndong].peasycap->
-									pusb_device) {
-				peasycap = easycapdc60_dongle[ndong].peasycap;
-				JOT(8, "intf[%i]: dongle[%i].peasycap\n",
-						bInterfaceNumber, ndong);
-				break;
+static int easycap_usb_probe(struct usb_interface *intf,
+			    const struct usb_device_id *id)
+{
+	struct usb_device *usbdev;
+	struct usb_host_interface *alt;
+	struct usb_endpoint_descriptor *ep;
+	struct usb_interface_descriptor *interface;
+	struct urb *purb;
+	struct easycap *peasycap;
+	struct data_urb *pdata_urb;
+	int i, j, k, m, rc;
+	u8 bInterfaceNumber;
+	u8 bInterfaceClass;
+	u8 bInterfaceSubClass;
+	void *pbuf;
+	int okalt[8], isokalt;
+	int okepn[8];
+	int okmps[8];
+	int maxpacketsize;
+
+	usbdev = interface_to_usbdev(intf);
+
+	alt = usb_altnum_to_altsetting(intf, 0);
+	if (!alt) {
+		SAY("ERROR: usb_host_interface not found\n");
+		return -EFAULT;
 	}
+
+	interface = &alt->desc;
+	if (!interface) {
+		SAY("ERROR: intf_descriptor is NULL\n");
+		return -EFAULT;
 	}
-		if (DONGLE_MANY <= ndong) {
-			SAY("ERROR: peasycap is unknown when probing interface %i\n",
-								bInterfaceNumber);
-			return -ENODEV;
+
+	/* Get properties of probed interface */
+	bInterfaceNumber = interface->bInterfaceNumber;
+	bInterfaceClass = interface->bInterfaceClass;
+	bInterfaceSubClass = interface->bInterfaceSubClass;
+
+	JOT(4, "intf[%i]: num_altsetting=%i\n",
+			bInterfaceNumber, intf->num_altsetting);
+	JOT(4, "intf[%i]: cur_altsetting - altsetting=%li\n",
+		bInterfaceNumber,
+		(long int)(intf->cur_altsetting - intf->altsetting));
+	JOT(4, "intf[%i]: bInterfaceClass=0x%02X bInterfaceSubClass=0x%02X\n",
+			bInterfaceNumber, bInterfaceClass, bInterfaceSubClass);
+
+	/*
+	 * A new struct easycap is always allocated when interface 0 is probed.
+	 * It is not possible here to free any existing struct easycap.
+	 * This should have been done by easycap_delete() when the device was
+	 * physically unplugged.
+	 * The allocated struct easycap is saved for later usage when
+	 * interfaces 1 and 2 are probed.
+	 */
+	if (0 == bInterfaceNumber) {
+		/*
+		 * Alloc structure and save it in a free slot in
+		 * easycapdc60_dongle array
+		 */
+		peasycap = alloc_easycap(bInterfaceNumber);
+		if (!peasycap)
+			return -ENOMEM;
+
+		/* Perform basic struct initialization */
+		init_easycap(peasycap, usbdev, intf, bInterfaceNumber);
+
+		/* Dynamically fill in the available formats */
+		rc = easycap_video_fillin_formats();
+		if (0 > rc) {
+			SAM("ERROR: fillin_formats() rc = %i\n", rc);
+			return -EFAULT;
 		}
-		if (!peasycap) {
-			SAY("ERROR: peasycap is NULL when probing interface %i\n",
-								bInterfaceNumber);
+		JOM(4, "%i formats available\n", rc);
+
+		/* Populate easycap.inputset[] */
+		rc = populate_inputset(peasycap);
+		if (rc < 0)
+			return rc;
+		JOM(4, "finished initialization\n");
+	} else {
+		peasycap = get_easycap(usbdev, bInterfaceNumber);
+		if (!peasycap)
 			return -ENODEV;
 	}
-	}
 
 	if ((USB_CLASS_VIDEO == bInterfaceClass) ||
 	    (USB_CLASS_VENDOR_SPEC == bInterfaceClass)) {