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Commit 15a98fb2 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Mauro Carvalho Chehab
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media: dvb_frontend: split dvb_frontend_handle_ioctl function 



Over time, dvb_frontend_handle_ioctl() has grown to the point where
we now get a warning from the compiler about excessive stack usage:

drivers/media/dvb-core/dvb_frontend.c: In function 'dvb_frontend_handle_ioctl':
drivers/media/dvb-core/dvb_frontend.c:2692:1: error: the frame size of 1048 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Almost all of this is used by the dtv_frontend_properties structure
in the FE_GET_PROPERTY and FE_GET_FRONTEND commands. Splitting those
into separate function reduces the stack usage of the main function
to just 136 bytes, the others are under 500 each.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarSean Young <sean@mess.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent a91418ac

drivers/media/dvb-core/dvb_frontend.c

+77 −63
Original line number Diff line number Diff line
@@ -2311,21 +2311,15 @@ static int dtv_set_frontend(struct dvb_frontend *fe) 
	return 0;

}



static int dvb_frontend_handle_ioctl(struct file *file,

				     unsigned int cmd, void *parg)

static int dvb_get_property(struct dvb_frontend *fe, struct file *file,

			    struct dtv_properties *tvps)

{

	struct dvb_device *dvbdev = file->private_data;

	struct dvb_frontend *fe = dvbdev->priv;

	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	struct dtv_frontend_properties *c = &fe->dtv_property_cache;

	int i, err = -ENOTSUPP;



	dev_dbg(fe->dvb->device, "%s:\n", __func__);



	switch (cmd) {

	case FE_SET_PROPERTY: {

		struct dtv_properties *tvps = parg;

	struct dtv_property *tvp = NULL;

	struct dtv_frontend_properties getp;

	int i, err;



	memcpy(&getp, &fe->dtv_property_cache, sizeof(getp));



	dev_dbg(fe->dvb->device, "%s: properties.num = %d\n",

		__func__, tvps->num);
@@ -2336,30 +2330,74 @@ static int dvb_frontend_handle_ioctl(struct file *file, 
	 * Put an arbitrary limit on the number of messages that can

	 * be sent at once

	 */

		if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))

	if (!tvps->num || tvps->num > DTV_IOCTL_MAX_MSGS)

		return -EINVAL;



	tvp = memdup_user((void __user *)tvps->props, tvps->num * sizeof(*tvp));

	if (IS_ERR(tvp))

		return PTR_ERR(tvp);



	/*

	 * Let's use our own copy of property cache, in order to

	 * avoid mangling with DTV zigzag logic, as drivers might

	 * return crap, if they don't check if the data is available

	 * before updating the properties cache.

	 */

	if (fepriv->state != FESTATE_IDLE) {

		err = dtv_get_frontend(fe, &getp, NULL);

		if (err < 0)

			goto out;

	}

	for (i = 0; i < tvps->num; i++) {

			err = dtv_property_process_set(fe, file,

						       (tvp + i)->cmd,

						       (tvp + i)->u.data);

			if (err < 0) {

				kfree(tvp);

				return err;

		err = dtv_property_process_get(fe, &getp,

					       tvp + i, file);

		if (err < 0)

			goto out;

	}



	if (copy_to_user((void __user *)tvps->props, tvp,

			 tvps->num * sizeof(struct dtv_property))) {

		err = -EFAULT;

		goto out;

	}

		kfree(tvp);



	err = 0;

		break;

out:

	kfree(tvp);

	return err;

}



static int dvb_get_frontend(struct dvb_frontend *fe,

			    struct dvb_frontend_parameters *p_out)

{

	struct dtv_frontend_properties getp;



	/*

	 * Let's use our own copy of property cache, in order to

	 * avoid mangling with DTV zigzag logic, as drivers might

	 * return crap, if they don't check if the data is available

	 * before updating the properties cache.

	 */

	memcpy(&getp, &fe->dtv_property_cache, sizeof(getp));



	return dtv_get_frontend(fe, &getp, p_out);

}

	case FE_GET_PROPERTY: {



static int dvb_frontend_handle_ioctl(struct file *file,

				     unsigned int cmd, void *parg)

{

	struct dvb_device *dvbdev = file->private_data;

	struct dvb_frontend *fe = dvbdev->priv;

	struct dvb_frontend_private *fepriv = fe->frontend_priv;

	struct dtv_frontend_properties *c = &fe->dtv_property_cache;

	int i, err = -ENOTSUPP;



	dev_dbg(fe->dvb->device, "%s:\n", __func__);



	switch (cmd) {

	case FE_SET_PROPERTY: {

		struct dtv_properties *tvps = parg;

		struct dtv_property *tvp = NULL;

		struct dtv_frontend_properties getp = fe->dtv_property_cache;



		dev_dbg(fe->dvb->device, "%s: properties.num = %d\n",

			__func__, tvps->num);
@@ -2377,37 +2415,22 @@ static int dvb_frontend_handle_ioctl(struct file *file, 
		if (IS_ERR(tvp))

			return PTR_ERR(tvp);



		/*

		 * Let's use our own copy of property cache, in order to

		 * avoid mangling with DTV zigzag logic, as drivers might

		 * return crap, if they don't check if the data is available

		 * before updating the properties cache.

		 */

		if (fepriv->state != FESTATE_IDLE) {

			err = dtv_get_frontend(fe, &getp, NULL);

			if (err < 0) {

				kfree(tvp);

				return err;

			}

		}

		for (i = 0; i < tvps->num; i++) {

			err = dtv_property_process_get(fe, &getp,

						       tvp + i, file);

			err = dtv_property_process_set(fe, file,

						       (tvp + i)->cmd,

						       (tvp + i)->u.data);

			if (err < 0) {

				kfree(tvp);

				return err;

			}

		}



		if (copy_to_user((void __user *)tvps->props, tvp,

				 tvps->num * sizeof(struct dtv_property))) {

			kfree(tvp);

			return -EFAULT;

		}

		kfree(tvp);

		err = 0;

		break;

	}

	case FE_GET_PROPERTY:

		err = dvb_get_property(fe, file, parg);

		break;



	case FE_GET_INFO: {

		struct dvb_frontend_info *info = parg;
@@ -2545,7 +2568,6 @@ static int dvb_frontend_handle_ioctl(struct file *file, 
		fepriv->tune_mode_flags = (unsigned long)parg;

		err = 0;

		break;



	/* DEPRECATED dish control ioctls */



	case FE_DISHNETWORK_SEND_LEGACY_CMD:
@@ -2664,22 +2686,14 @@ static int dvb_frontend_handle_ioctl(struct file *file, 
			break;

		err = dtv_set_frontend(fe);

		break;



	case FE_GET_EVENT:

		err = dvb_frontend_get_event(fe, parg, file->f_flags);

		break;



	case FE_GET_FRONTEND: {

		struct dtv_frontend_properties getp = fe->dtv_property_cache;



		/*

		 * Let's use our own copy of property cache, in order to

		 * avoid mangling with DTV zigzag logic, as drivers might

		 * return crap, if they don't check if the data is available

		 * before updating the properties cache.

		 */

		err = dtv_get_frontend(fe, &getp, parg);

	case FE_GET_FRONTEND:

		err = dvb_get_frontend(fe, parg);

		break;

	}



	default:

		return -ENOTSUPP;