From 15a98fb2fc287bbfe430e854d56dcfc86eae21db Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 17 Jun 2019 07:16:52 -0400 Subject: 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: Arnd Bergmann Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-core/dvb_frontend.c | 140 +++++++++++++++++++--------------- 1 file changed, 77 insertions(+), 63 deletions(-) (limited to 'drivers/media') diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index 6351a97f3d18..209186c5cd9b 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -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; -- cgit v1.2.3-59-g8ed1b