[media] gspca: Don't set gspca_dev->dev to NULL before stop0
In commit a3d6e8cc0e6ddc8b3cfdeb3c979f07ed1aa528b3 gspca_dev->dev is set
to NULL on disconnect, before calling stop0. The plan was to get rid of
gspca_dev->present and instead simply check for gspca_dev->dev everywhere
where we were checking for present. This should be race free since all users
of gspca_dev->dev hold the usb_lock, or so I thought.
But I was wrong, drivers which use a work-queue + synchronous bulk transfers
to get the video data don't hold the usb_lock while doing so, their stop0
callbacks stop the workqueue, so they won't be using gspca_dev->dev anymore
after the stop0 call, but they might be dereferincing it before, so we should
not set gspca_dev->dev to NULL on disconnect before calling stop0.
This also means that the workqueue functions in these drivers cannot
use gspca_dev->dev to check if they need to stop because of disconnection,
so we will need to keep gspca_dev->present around, and set that to 0 on
disconnect, before calling stop0. Unfortunately as part of the plan to remove
gspca_dev->present, these workqueues where already moved over to checking
for gspca_dev->dev instead of gspca_dev->present as part of commit
254902b01d2acc6aced99ec17caa4c6cd890cdea, so this patch also reverts those
parts of that commit.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/usb/gspca/finepix.c b/drivers/media/usb/gspca/finepix.c
index c8f2201..04807ee 100644
--- a/drivers/media/usb/gspca/finepix.c
+++ b/drivers/media/usb/gspca/finepix.c
@@ -94,7 +94,7 @@
/* loop reading a frame */
again:
- while (gspca_dev->dev && gspca_dev->streaming) {
+ while (gspca_dev->present && gspca_dev->streaming) {
#ifdef CONFIG_PM
if (gspca_dev->frozen)
break;
@@ -110,7 +110,7 @@
if (gspca_dev->frozen)
break;
#endif
- if (!gspca_dev->dev || !gspca_dev->streaming)
+ if (!gspca_dev->present || !gspca_dev->streaming)
break;
/* the frame comes in parts */
@@ -129,7 +129,7 @@
if (gspca_dev->frozen)
goto out;
#endif
- if (!gspca_dev->dev || !gspca_dev->streaming)
+ if (!gspca_dev->present || !gspca_dev->streaming)
goto out;
if (len < FPIX_MAX_TRANSFER ||
(data[len - 2] == 0xff &&