[media] gspca: Fix locking issues related to suspend/resume
There are two bugs here: first the calls to stop0 (in gspca_suspend) and
gspca_init_transfer (in gspca_resume) need to be called with the usb_lock held.
That's true for the other places they are called and it is what subdrivers
expect. Quite a few will unlock the usb_lock in stop0 while waiting for a
worker thread to finish, and if usb_lock isn't held then that can cause a
kernel oops.
The other problem is that a worker thread needs to detect that it has to
halt due to a suspend. Otherwise it will just go on looping. So add tests
against gspca_dev->frozen in the worker threads that need it.
Hdg, 2 minor changes:
1) The finepix device is ok with stopping reading a frame halfway through,
so add frozen checks in all places where we also check if we're still
streaming
2) Use gspca_dev->dev instead of gspca_dev->present to check for disconnect
in all touched drivers. I plan to do this everywhere in the future, and
most relevant lines in the touched drivers are already modified by this
patch.
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/sq905.c b/drivers/media/video/gspca/sq905.c
index 2fe3c29..a144ce7 100644
--- a/drivers/media/video/gspca/sq905.c
+++ b/drivers/media/video/gspca/sq905.c
@@ -232,7 +232,7 @@
frame_sz = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].sizeimage
+ FRAME_HEADER_LEN;
- while (gspca_dev->present && gspca_dev->streaming) {
+ while (!gspca_dev->frozen && gspca_dev->dev && gspca_dev->streaming) {
/* request some data and then read it until we have
* a complete frame. */
bytes_left = frame_sz;
@@ -242,7 +242,7 @@
we must finish reading an entire frame, otherwise the
next time we stream we start reading in the middle of a
frame. */
- while (bytes_left > 0 && gspca_dev->present) {
+ while (bytes_left > 0 && gspca_dev->dev) {
data_len = bytes_left > SQ905_MAX_TRANSFER ?
SQ905_MAX_TRANSFER : bytes_left;
ret = sq905_read_data(gspca_dev, buffer, data_len, 1);
@@ -274,7 +274,7 @@
gspca_frame_add(gspca_dev, LAST_PACKET,
NULL, 0);
}
- if (gspca_dev->present) {
+ if (gspca_dev->dev) {
/* acknowledge the frame */
mutex_lock(&gspca_dev->usb_lock);
ret = sq905_ack_frame(gspca_dev);
@@ -284,7 +284,7 @@
}
}
quit_stream:
- if (gspca_dev->present) {
+ if (gspca_dev->dev) {
mutex_lock(&gspca_dev->usb_lock);
sq905_command(gspca_dev, SQ905_CLEAR);
mutex_unlock(&gspca_dev->usb_lock);