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authorBhaktipriya Shridhar <bhaktipriya96@gmail.com>2016-07-09 04:52:29 -0300
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2016-07-09 07:43:53 -0300
commitf7cf0362f6ad13e1235a731456641178a4280c90 (patch)
treebfec4efc155c746eb761da8d409162dddee4bdf2 /drivers/media/usb/gspca
parente0f80d8d62f50d7df0ce7eacd1246fcafd1e40be (diff)
[media] zc3xx: Remove deprecated create_singlethread_workqueue
The workqueue "work_thread" is involved in updating parameters for transfers. It has a single work item(&sd->work) and hence doesn't require ordering. Also, it is not being used on a memory reclaim path. Hence, the singlethreaded workqueue has been replaced with the use of system_wq. System workqueues have been able to handle high level of concurrency for a long time now and hence it's not required to have a singlethreaded workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue created with create_singlethread_workqueue(), system_wq allows multiple work items to overlap executions even on the same CPU; however, a per-cpu workqueue doesn't have any CPU locality or global ordering guarantee unless the target CPU is explicitly specified and thus the increase of local concurrency shouldn't make any difference. Work item has been flushed in sd_stop0() to ensure that there are no pending tasks while disconnecting the driver. Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media/usb/gspca')
-rw-r--r--drivers/media/usb/gspca/zc3xx.c13
1 files changed, 4 insertions, 9 deletions
diff --git a/drivers/media/usb/gspca/zc3xx.c b/drivers/media/usb/gspca/zc3xx.c
index c5d8ee6fa3c7..5f7254d2bc9a 100644
--- a/drivers/media/usb/gspca/zc3xx.c
+++ b/drivers/media/usb/gspca/zc3xx.c
@@ -53,7 +53,6 @@ struct sd {
struct v4l2_ctrl *jpegqual;
struct work_struct work;
- struct workqueue_struct *work_thread;
u8 reg08; /* webcam compression quality */
@@ -6826,8 +6825,7 @@ static int sd_start(struct gspca_dev *gspca_dev)
return gspca_dev->usb_err;
/* Start the transfer parameters update thread */
- sd->work_thread = create_singlethread_workqueue(KBUILD_MODNAME);
- queue_work(sd->work_thread, &sd->work);
+ schedule_work(&sd->work);
return 0;
}
@@ -6838,12 +6836,9 @@ static void sd_stop0(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
- if (sd->work_thread != NULL) {
- mutex_unlock(&gspca_dev->usb_lock);
- destroy_workqueue(sd->work_thread);
- mutex_lock(&gspca_dev->usb_lock);
- sd->work_thread = NULL;
- }
+ mutex_unlock(&gspca_dev->usb_lock);
+ flush_work(&sd->work);
+ mutex_lock(&gspca_dev->usb_lock);
if (!gspca_dev->present)
return;
send_unknown(gspca_dev, sd->sensor);