[media] gspca: Update / fix various comments wrt workqueue usb_lock usage

[~andy/linux] / drivers / media / usb / gspca / finepix.c

diff --git a/drivers/media/usb/gspca/finepix.c b/drivers/media/usb/gspca/finepix.c
index fb68a2934255ac58e2135a1fc5724ed3648f382c..52bdb569760b4139bb20dfca693746b5a267ddf6 100644 (file)
--- a/drivers/media/usb/gspca/finepix.c
+++ b/drivers/media/usb/gspca/finepix.c
@@ -77,7 +77,14 @@ static int command(struct gspca_dev *gspca_dev,
                        12, FPIX_TIMEOUT);
 }
 
-/* workqueue */
+/*
+ * This function is called as a workqueue function and runs whenever the camera
+ * is streaming data. Because it is a workqueue function it is allowed to sleep
+ * so we can use synchronous USB calls. To avoid possible collisions with other
+ * threads attempting to use gspca_dev->usb_buf we take the usb_lock when
+ * performing USB operations using it. In practice we don't really need this
+ * as the camera doesn't provide any controls.
+ */
 static void dostream(struct work_struct *work)
 {
        struct usb_fpix *dev = container_of(work, struct usb_fpix, work_struct);