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Message-Id: <20240926-guenter-mini-v7-1-690441953d4a@chromium.org>
Date: Thu, 26 Sep 2024 05:49:57 +0000
From: Ricardo Ribalda <ribalda@...omium.org>
To: Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: Guenter Roeck <linux@...ck-us.net>, Tomasz Figa <tfiga@...omium.org>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Alan Stern <stern@...land.harvard.edu>,
Hans Verkuil <hverkuil-cisco@...all.nl>, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org, Sean Paul <seanpaul@...omium.org>,
Ricardo Ribalda <ribalda@...omium.org>,
Sakari Ailus <sakari.ailus@...ux.intel.com>,
Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCH v7 1/3] media: uvcvideo: Refactor the status irq API
There are two different use-cases of uvc_status():
- adding/removing a user when the camera is open/closed
- stopping/starting when the camera is suspended/resumed
Make the API reflect these two use-cases and move all the refcounting
and locking logic to the uvc_status.c file.
No functional change is expected from this patch.
Reviewed-by: Sergey Senozhatsky <senozhatsky@...omium.org>
Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
---
drivers/media/usb/uvc/uvc_driver.c | 13 ++--------
drivers/media/usb/uvc/uvc_status.c | 53 ++++++++++++++++++++++++++++++++++++--
drivers/media/usb/uvc/uvc_v4l2.c | 22 +++++-----------
drivers/media/usb/uvc/uvcvideo.h | 10 ++++---
4 files changed, 65 insertions(+), 33 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index f0febdc08c2d..31e8942f1ef8 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2116,7 +2116,6 @@ static int uvc_probe(struct usb_interface *intf,
INIT_LIST_HEAD(&dev->streams);
kref_init(&dev->ref);
atomic_set(&dev->nmappings, 0);
- mutex_init(&dev->lock);
dev->udev = usb_get_dev(udev);
dev->intf = usb_get_intf(intf);
@@ -2288,10 +2287,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message)
/* Controls are cached on the fly so they don't need to be saved. */
if (intf->cur_altsetting->desc.bInterfaceSubClass ==
UVC_SC_VIDEOCONTROL) {
- mutex_lock(&dev->lock);
- if (dev->users)
- uvc_status_stop(dev);
- mutex_unlock(&dev->lock);
+ uvc_status_suspend(dev);
return 0;
}
@@ -2322,12 +2318,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset)
return ret;
}
- mutex_lock(&dev->lock);
- if (dev->users)
- ret = uvc_status_start(dev, GFP_NOIO);
- mutex_unlock(&dev->lock);
-
- return ret;
+ return uvc_status_resume(dev);
}
list_for_each_entry(stream, &dev->streams, list) {
diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index a78a88c710e2..e438ae5af2e8 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -257,6 +257,8 @@ int uvc_status_init(struct uvc_device *dev)
unsigned int pipe;
int interval;
+ mutex_init(&dev->status_lock);
+
if (ep == NULL)
return 0;
@@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev)
kfree(dev->status);
}
-int uvc_status_start(struct uvc_device *dev, gfp_t flags)
+static int uvc_status_start(struct uvc_device *dev, gfp_t flags)
{
+ lockdep_assert_held(&dev->status_lock);
+
if (dev->int_urb == NULL)
return 0;
return usb_submit_urb(dev->int_urb, flags);
}
-void uvc_status_stop(struct uvc_device *dev)
+static void uvc_status_stop(struct uvc_device *dev)
{
struct uvc_ctrl_work *w = &dev->async_ctrl;
+ lockdep_assert_held(&dev->status_lock);
+
/*
* Prevent the asynchronous control handler from requeing the URB. The
* barrier is needed so the flush_status change is visible to other
@@ -350,3 +356,46 @@ void uvc_status_stop(struct uvc_device *dev)
*/
smp_store_release(&dev->flush_status, false);
}
+
+int uvc_status_resume(struct uvc_device *dev)
+{
+ guard(mutex)(&dev->status_lock);
+
+ if (dev->status_users)
+ return uvc_status_start(dev, GFP_NOIO);
+
+ return 0;
+}
+
+void uvc_status_suspend(struct uvc_device *dev)
+{
+ guard(mutex)(&dev->status_lock);
+
+ if (dev->status_users)
+ uvc_status_stop(dev);
+}
+
+int uvc_status_get(struct uvc_device *dev)
+{
+ int ret = 0;
+
+ guard(mutex)(&dev->status_lock);
+
+ if (!dev->status_users)
+ ret = uvc_status_start(dev, GFP_KERNEL);
+ if (!ret)
+ dev->status_users++;
+
+ return ret;
+}
+
+void uvc_status_put(struct uvc_device *dev)
+{
+ guard(mutex)(&dev->status_lock);
+
+ if (dev->status_users == 1)
+ uvc_status_stop(dev);
+ WARN_ON(!dev->status_users);
+ if (dev->status_users)
+ dev->status_users--;
+}
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4988f03640a..97c5407f6603 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file)
return -ENOMEM;
}
- mutex_lock(&stream->dev->lock);
- if (stream->dev->users == 0) {
- ret = uvc_status_start(stream->dev, GFP_KERNEL);
- if (ret < 0) {
- mutex_unlock(&stream->dev->lock);
- usb_autopm_put_interface(stream->dev->intf);
- kfree(handle);
- return ret;
- }
+ ret = uvc_status_get(stream->dev);
+ if (ret) {
+ usb_autopm_put_interface(stream->dev->intf);
+ kfree(handle);
+ return ret;
}
- stream->dev->users++;
- mutex_unlock(&stream->dev->lock);
-
v4l2_fh_init(&handle->vfh, &stream->vdev);
v4l2_fh_add(&handle->vfh);
handle->chain = stream->chain;
@@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file)
kfree(handle);
file->private_data = NULL;
- mutex_lock(&stream->dev->lock);
- if (--stream->dev->users == 0)
- uvc_status_stop(stream->dev);
- mutex_unlock(&stream->dev->lock);
+ uvc_status_put(stream->dev);
usb_autopm_put_interface(stream->dev->intf);
return 0;
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index b7d24a853ce4..07f9921d83f2 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -563,8 +563,6 @@ struct uvc_device {
const struct uvc_device_info *info;
- struct mutex lock; /* Protects users */
- unsigned int users;
atomic_t nmappings;
/* Video control interface */
@@ -586,6 +584,8 @@ struct uvc_device {
struct usb_host_endpoint *int_ep;
struct urb *int_urb;
struct uvc_status *status;
+ struct mutex status_lock; /* Protects status_users */
+ unsigned int status_users;
bool flush_status;
struct input_dev *input;
@@ -752,8 +752,10 @@ int uvc_register_video_device(struct uvc_device *dev,
int uvc_status_init(struct uvc_device *dev);
void uvc_status_unregister(struct uvc_device *dev);
void uvc_status_cleanup(struct uvc_device *dev);
-int uvc_status_start(struct uvc_device *dev, gfp_t flags);
-void uvc_status_stop(struct uvc_device *dev);
+int uvc_status_resume(struct uvc_device *dev);
+void uvc_status_suspend(struct uvc_device *dev);
+int uvc_status_get(struct uvc_device *dev);
+void uvc_status_put(struct uvc_device *dev);
/* Controls */
extern const struct v4l2_subscribed_event_ops uvc_ctrl_sub_ev_ops;
--
2.46.1.824.gd892dcdcdd-goog
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