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authorBhaktipriya Shridhar <bhaktipriya96@gmail.com>2016-07-16 05:53:48 -0300
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2016-08-24 09:29:56 -0300
commite59646895778f1e645b4e2f02d99aaec7a144ce1 (patch)
treecd522517955028c3fd62b6b4db8f9f249a9cbc13 /drivers/media/usb/gspca
parent[media] gspca: vicam: Remove deprecated create_singlethread_workqueue (diff)
downloadlinux-dev-e59646895778f1e645b4e2f02d99aaec7a144ce1.tar.xz
linux-dev-e59646895778f1e645b4e2f02d99aaec7a144ce1.zip
[media] gspca: jl2005bcd: Remove deprecated create_singlethread_workqueue
The workqueue "work_thread" is involved in streaming the camera data. It has a single work item(&sd->work_struct) 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> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.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/jl2005bcd.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/drivers/media/usb/gspca/jl2005bcd.c b/drivers/media/usb/gspca/jl2005bcd.c
index 5b481fa43099..ac295f04bd18 100644
--- a/drivers/media/usb/gspca/jl2005bcd.c
+++ b/drivers/media/usb/gspca/jl2005bcd.c
@@ -45,7 +45,6 @@ struct sd {
const struct v4l2_pix_format *cap_mode;
/* Driver stuff */
struct work_struct work_struct;
- struct workqueue_struct *work_thread;
u8 frame_brightness;
int block_size; /* block size of camera */
int vga; /* 1 if vga cam, 0 if cif cam */
@@ -477,9 +476,7 @@ static int sd_start(struct gspca_dev *gspca_dev)
return -1;
}
- /* Start the workqueue function to do the streaming */
- sd->work_thread = create_singlethread_workqueue(MODULE_NAME);
- queue_work(sd->work_thread, &sd->work_struct);
+ schedule_work(&sd->work_struct);
return 0;
}
@@ -493,8 +490,7 @@ static void sd_stop0(struct gspca_dev *gspca_dev)
/* wait for the work queue to terminate */
mutex_unlock(&gspca_dev->usb_lock);
/* This waits for sq905c_dostream to finish */
- destroy_workqueue(dev->work_thread);
- dev->work_thread = NULL;
+ flush_work(&dev->work_struct);
mutex_lock(&gspca_dev->usb_lock);
}