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Message-Id: <20190617111718.2277220-2-arnd@arndb.de>
Date: Mon, 17 Jun 2019 13:16:52 +0200
From: Arnd Bergmann <arnd@...db.de>
To: Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: Arnd Bergmann <arnd@...db.de>,
Hans Verkuil <hans.verkuil@...co.com>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] 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 <arnd@...db.de>
---
drivers/media/dvb-core/dvb_frontend.c | 140 ++++++++++++++------------
1 file changed, 77 insertions(+), 63 deletions(-)
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index 2dc7761a3680..202f0ba5819c 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -2314,6 +2314,78 @@ 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)
{
@@ -2359,58 +2431,9 @@ 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;
@@ -2548,7 +2571,6 @@ 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:
@@ -2667,22 +2689,14 @@ 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;
--
2.20.0
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