From 345321dc9c52b774f42c934339f9b3e2f0a39395 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 9 Sep 2012 06:30:02 -0300 Subject: [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 Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/gspca/vicam.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/media/usb/gspca/vicam.c') diff --git a/drivers/media/usb/gspca/vicam.c b/drivers/media/usb/gspca/vicam.c index b1a64b912666..57d88f70c399 100644 --- a/drivers/media/usb/gspca/vicam.c +++ b/drivers/media/usb/gspca/vicam.c @@ -194,7 +194,7 @@ static void vicam_dostream(struct work_struct *work) goto exit; } - while (gspca_dev->dev && gspca_dev->streaming) { + while (gspca_dev->present && gspca_dev->streaming) { #ifdef CONFIG_PM if (gspca_dev->frozen) break; @@ -299,7 +299,7 @@ static void sd_stop0(struct gspca_dev *gspca_dev) dev->work_thread = NULL; mutex_lock(&gspca_dev->usb_lock); - if (gspca_dev->dev) + if (gspca_dev->present) vicam_set_camera_power(gspca_dev, 0); } -- cgit v1.2.3-55-g7522