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Commit 345321dc authored by Hans de Goede's avatar Hans de Goede Committed by Mauro Carvalho Chehab
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[media] gspca: Don't set gspca_dev->dev to NULL before stop0 



In commit a3d6e8cc 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
254902b0, so this patch also reverts those
parts of that commit.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 8c96f0a2

drivers/media/usb/gspca/finepix.c

+3 −3
Original line number Diff line number Diff line
@@ -94,7 +94,7 @@ static void dostream(struct work_struct *work) 


	/* 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 @@ static void dostream(struct work_struct *work) 
		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 @@ static void dostream(struct work_struct *work) 
			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 &&

drivers/media/usb/gspca/gspca.c

+1 −2
Original line number Diff line number Diff line
@@ -2358,8 +2358,6 @@ void gspca_disconnect(struct usb_interface *intf) 


	mutex_lock(&gspca_dev->usb_lock);



	usb_set_intfdata(intf, NULL);

	gspca_dev->dev = NULL;

	gspca_dev->present = 0;

	destroy_urbs(gspca_dev);
@@ -2375,6 +2373,7 @@ void gspca_disconnect(struct usb_interface *intf) 
	if (gspca_dev->sd_desc->stop0 && gspca_dev->streaming)

		gspca_dev->sd_desc->stop0(gspca_dev);

	gspca_dev->streaming = 0;

	gspca_dev->dev = NULL;

	wake_up_interruptible(&gspca_dev->wq);



	v4l2_device_disconnect(&gspca_dev->v4l2_dev);

drivers/media/usb/gspca/jl2005bcd.c

+3 −3
Original line number Diff line number Diff line
@@ -335,7 +335,7 @@ static void jl2005c_dostream(struct work_struct *work) 
		goto quit_stream;

	}



	while (gspca_dev->dev && gspca_dev->streaming) {

	while (gspca_dev->present && gspca_dev->streaming) {

#ifdef CONFIG_PM

		if (gspca_dev->frozen)

			break;
@@ -371,7 +371,7 @@ static void jl2005c_dostream(struct work_struct *work) 
					buffer, act_len);

			header_read = 1;

		}

		while (bytes_left > 0 && gspca_dev->dev) {

		while (bytes_left > 0 && gspca_dev->present) {

			data_len = bytes_left > JL2005C_MAX_TRANSFER ?

				JL2005C_MAX_TRANSFER : bytes_left;

			ret = usb_bulk_msg(gspca_dev->dev,
@@ -394,7 +394,7 @@ static void jl2005c_dostream(struct work_struct *work) 
		}

	}

quit_stream:

	if (gspca_dev->dev) {

	if (gspca_dev->present) {

		mutex_lock(&gspca_dev->usb_lock);

		jl2005c_stop(gspca_dev);

		mutex_unlock(&gspca_dev->usb_lock);

drivers/media/usb/gspca/sq905.c

+4 −4
Original line number Diff line number Diff line
@@ -232,7 +232,7 @@ static void sq905_dostream(struct work_struct *work) 
	frame_sz = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].sizeimage

			+ FRAME_HEADER_LEN;



	while (gspca_dev->dev && gspca_dev->streaming) {

	while (gspca_dev->present && gspca_dev->streaming) {

#ifdef CONFIG_PM

		if (gspca_dev->frozen)

			break;
@@ -246,7 +246,7 @@ static void sq905_dostream(struct work_struct *work) 
		   we must finish reading an entire frame, otherwise the

		   next time we stream we start reading in the middle of a

		   frame. */

		while (bytes_left > 0 && gspca_dev->dev) {

		while (bytes_left > 0 && gspca_dev->present) {

			data_len = bytes_left > SQ905_MAX_TRANSFER ?

				SQ905_MAX_TRANSFER : bytes_left;

			ret = sq905_read_data(gspca_dev, buffer, data_len, 1);
@@ -278,7 +278,7 @@ static void sq905_dostream(struct work_struct *work) 
				gspca_frame_add(gspca_dev, LAST_PACKET,

						NULL, 0);

		}

		if (gspca_dev->dev) {

		if (gspca_dev->present) {

			/* acknowledge the frame */

			mutex_lock(&gspca_dev->usb_lock);

			ret = sq905_ack_frame(gspca_dev);
@@ -288,7 +288,7 @@ static void sq905_dostream(struct work_struct *work) 
		}

	}

quit_stream:

	if (gspca_dev->dev) {

	if (gspca_dev->present) {

		mutex_lock(&gspca_dev->usb_lock);

		sq905_command(gspca_dev, SQ905_CLEAR);

		mutex_unlock(&gspca_dev->usb_lock);

drivers/media/usb/gspca/sq905c.c

+3 −3
Original line number Diff line number Diff line
@@ -150,7 +150,7 @@ static void sq905c_dostream(struct work_struct *work) 
		goto quit_stream;

	}



	while (gspca_dev->dev && gspca_dev->streaming) {

	while (gspca_dev->present && gspca_dev->streaming) {

#ifdef CONFIG_PM

		if (gspca_dev->frozen)

			break;
@@ -173,7 +173,7 @@ static void sq905c_dostream(struct work_struct *work) 
		packet_type = FIRST_PACKET;

		gspca_frame_add(gspca_dev, packet_type,

				buffer, FRAME_HEADER_LEN);

		while (bytes_left > 0 && gspca_dev->dev) {

		while (bytes_left > 0 && gspca_dev->present) {

			data_len = bytes_left > SQ905C_MAX_TRANSFER ?

				SQ905C_MAX_TRANSFER : bytes_left;

			ret = usb_bulk_msg(gspca_dev->dev,
@@ -195,7 +195,7 @@ static void sq905c_dostream(struct work_struct *work) 
		}

	}

quit_stream:

	if (gspca_dev->dev) {

	if (gspca_dev->present) {

		mutex_lock(&gspca_dev->usb_lock);

		sq905c_command(gspca_dev, SQ905C_CLEAR, 0);

		mutex_unlock(&gspca_dev->usb_lock);