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From: Arnd Bergmann <arnd@kernel.org>
To: Mike Isely <isely@pobox.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	"Ricardo B. Marliere" <ricardo@marliere.net>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Michael Krufky <mkrufky@linuxtv.org>,
	linux-media@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH] media: pvrusb2: fix pvr2_stream_callback casts
Date: Tue, 13 Feb 2024 11:04:27 +0100
Message-Id: <20240213100439.457403-1-arnd@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: Arnd Bergmann <arnd@arndb.de>

clang-16 complains about a control flow integrity (KCFI) issue in pvrusb2,
which casts three different prototypes into pvr2_stream_callback:

drivers/media/usb/pvrusb2/pvrusb2-v4l2.c:1070:30: error: cast from 'void (*)(struct pvr2_v4l2_fh *)' to 'pvr2_stream_callback' (aka 'void (*)(void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
 1070 |         pvr2_stream_set_callback(sp,(pvr2_stream_callback)pvr2_v4l2_notify,fh);
      |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/usb/pvrusb2/pvrusb2-context.c:110:6: error: cast from 'void (*)(struct pvr2_context *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
  110 |                                         (void (*)(void *))pvr2_context_notify,
      |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/usb/pvrusb2/pvrusb2-dvb.c:152:6: error: cast from 'void (*)(struct pvr2_dvb_adapter *)' to 'pvr2_stream_callback' (aka 'void (*)(void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
  152 |                                  (pvr2_stream_callback) pvr2_dvb_notify, adap);
      |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change the functions to actually take a void* argument so the cast is no longer
needed.

Fixes: bb8ce9d9143c ("V4L/DVB (7682): pvrusb2-dvb: finish up stream & buffer handling")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/media/usb/pvrusb2/pvrusb2-context.c | 8 ++++----
 drivers/media/usb/pvrusb2/pvrusb2-dvb.c     | 6 ++++--
 drivers/media/usb/pvrusb2/pvrusb2-v4l2.c    | 6 ++++--
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c
index 1764674de98b..58f2f3ff10ee 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-context.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c
@@ -90,8 +90,10 @@ static void pvr2_context_destroy(struct pvr2_context *mp)
 }
 
 
-static void pvr2_context_notify(struct pvr2_context *mp)
+static void pvr2_context_notify(void *ptr)
 {
+	struct pvr2_context *mp = ptr;
+
 	pvr2_context_set_notify(mp,!0);
 }
 
@@ -106,9 +108,7 @@ static void pvr2_context_check(struct pvr2_context *mp)
 		pvr2_trace(PVR2_TRACE_CTXT,
 			   "pvr2_context %p (initialize)", mp);
 		/* Finish hardware initialization */
-		if (pvr2_hdw_initialize(mp->hdw,
-					(void (*)(void *))pvr2_context_notify,
-					mp)) {
+		if (pvr2_hdw_initialize(mp->hdw, pvr2_context_notify, mp)) {
 			mp->video_stream.stream =
 				pvr2_hdw_get_video_stream(mp->hdw);
 			/* Trigger interface initialization.  By doing this
diff --git a/drivers/media/usb/pvrusb2/pvrusb2-dvb.c b/drivers/media/usb/pvrusb2/pvrusb2-dvb.c
index 26811efe0fb5..9a9bae21c614 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-dvb.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-dvb.c
@@ -88,8 +88,10 @@ static int pvr2_dvb_feed_thread(void *data)
 	return stat;
 }
 
-static void pvr2_dvb_notify(struct pvr2_dvb_adapter *adap)
+static void pvr2_dvb_notify(void *ptr)
 {
+	struct pvr2_dvb_adapter *adap = ptr;
+
 	wake_up(&adap->buffer_wait_data);
 }
 
@@ -149,7 +151,7 @@ static int pvr2_dvb_stream_do_start(struct pvr2_dvb_adapter *adap)
 	}
 
 	pvr2_stream_set_callback(pvr->video_stream.stream,
-				 (pvr2_stream_callback) pvr2_dvb_notify, adap);
+				 pvr2_dvb_notify, adap);
 
 	ret = pvr2_stream_set_buffer_count(stream, PVR2_DVB_BUFFER_COUNT);
 	if (ret < 0) return ret;
diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
index c04ab7258d64..b305ae7ed415 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
@@ -1033,8 +1033,10 @@ static int pvr2_v4l2_open(struct file *file)
 }
 
 
-static void pvr2_v4l2_notify(struct pvr2_v4l2_fh *fhp)
+static void pvr2_v4l2_notify(void *ptr)
 {
+	struct pvr2_v4l2_fh *fhp = ptr;
+
 	wake_up(&fhp->wait_data);
 }
 
@@ -1067,7 +1069,7 @@ static int pvr2_v4l2_iosetup(struct pvr2_v4l2_fh *fh)
 
 	hdw = fh->channel.mc_head->hdw;
 	sp = fh->pdi->stream->stream;
-	pvr2_stream_set_callback(sp,(pvr2_stream_callback)pvr2_v4l2_notify,fh);
+	pvr2_stream_set_callback(sp, pvr2_v4l2_notify, fh);
 	pvr2_hdw_set_stream_type(hdw,fh->pdi->config);
 	if ((ret = pvr2_hdw_set_streaming(hdw,!0)) < 0) return ret;
 	return pvr2_ioread_set_enabled(fh->rhp,!0);
-- 
2.39.2