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media: dvb_frontend: split dvb_frontend_handle_ioctl function

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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: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Arnd Bergmann 2019-06-17 07:16:52 -04:00 committed by Mauro Carvalho Chehab
parent a91418ac13
commit 15a98fb2fc
1 changed files with 77 additions and 63 deletions
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140
drivers/media/dvb-core/dvb_frontend.c
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@ -2311,6 +2311,78 @@ static int dtv_set_frontend(struct dvb_frontend *fe)
return 0;
}
static int dvb_get_property(struct dvb_frontend *fe, struct file *file,
struct dtv_properties *tvps)
{
struct dvb_frontend_private *fepriv = fe->frontend_priv;
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);
dev_dbg(fe->dvb->device, "%s: properties.props = %p\n",
__func__, tvps->props);
/*
* Put an arbitrary limit on the number of messages that can
* be sent at once
*/
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_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;
}
err = 0;
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);
}
static int dvb_frontend_handle_ioctl(struct file *file,
unsigned int cmd, void *parg)
{
@ -2356,58 +2428,9 @@ static int dvb_frontend_handle_ioctl(struct file *file,
err = 0;
break;
}
case FE_GET_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);
dev_dbg(fe->dvb->device, "%s: properties.props = %p\n",
__func__, tvps->props);
/*
* Put an arbitrary limit on the number of messages that can
* be sent at once
*/
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) {
kfree(tvp);
return err;
}
}
for (i = 0; i < tvps->num; i++) {
err = dtv_property_process_get(fe, &getp,
tvp + i, file);
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;
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;