treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

4 files changed, 8 insertions, 8 deletions

diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c
index 6ec277421390..e5bffaaeed38 100644
--- a/drivers/media/dvb-frontends/rtl2832.c
+++ b/drivers/media/dvb-frontends/rtl2832.c
@@ -640,7 +640,7 @@ static int rtl2832_read_status(struct dvb_frontend *fe, enum fe_status *status)
 	struct i2c_client *client = dev->client;
 	struct dtv_frontend_properties *c = &fe->dtv_property_cache;
 	int ret;
-	u32 uninitialized_var(tmp);
+	u32 tmp;
 	u8 u8tmp, buf[2];
 	u16 u16tmp;
 
diff --git a/drivers/media/tuners/qt1010.c b/drivers/media/tuners/qt1010.c
index 85bbdd4ecdbb..e48faf942830 100644
--- a/drivers/media/tuners/qt1010.c
+++ b/drivers/media/tuners/qt1010.c
@@ -215,7 +215,7 @@ static int qt1010_set_params(struct dvb_frontend *fe)
 static int qt1010_init_meas1(struct qt1010_priv *priv,
 			     u8 oper, u8 reg, u8 reg_init_val, u8 *retval)
 {
-	u8 i, val1, uninitialized_var(val2);
+	u8 i, val1, val2;
 	int err;
 
 	qt1010_i2c_oper_t i2c_data[] = {
@@ -250,7 +250,7 @@ static int qt1010_init_meas1(struct qt1010_priv *priv,
 static int qt1010_init_meas2(struct qt1010_priv *priv,
 			    u8 reg_init_val, u8 *retval)
 {
-	u8 i, uninitialized_var(val);
+	u8 i, val;
 	int err;
 	qt1010_i2c_oper_t i2c_data[] = {
 		{ QT1010_WR, 0x07, reg_init_val },
diff --git a/drivers/media/usb/gspca/vicam.c b/drivers/media/usb/gspca/vicam.c
index 179b2ec3df57..d98343fd33fe 100644
--- a/drivers/media/usb/gspca/vicam.c
+++ b/drivers/media/usb/gspca/vicam.c
@@ -225,7 +225,7 @@ static int sd_init(struct gspca_dev *gspca_dev)
 {
 	int ret;
 	const struct ihex_binrec *rec;
-	const struct firmware *uninitialized_var(fw);
+	const struct firmware *fw;
 	u8 *firmware_buf;
 
 	ret = request_ihex_firmware(&fw, VICAM_FIRMWARE,
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 8fa77a81dd7f..a65d5353a441 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -765,9 +765,9 @@ static void uvc_video_stats_decode(struct uvc_streaming *stream,
 	unsigned int header_size;
 	bool has_pts = false;
 	bool has_scr = false;
-	u16 uninitialized_var(scr_sof);
-	u32 uninitialized_var(scr_stc);
-	u32 uninitialized_var(pts);
+	u16 scr_sof;
+	u32 scr_stc;
+	u32 pts;
 
 	if (stream->stats.stream.nb_frames == 0 &&
 	    stream->stats.frame.nb_packets == 0)
@@ -1828,7 +1828,7 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
 		struct usb_host_endpoint *best_ep = NULL;
 		unsigned int best_psize = UINT_MAX;
 		unsigned int bandwidth;
-		unsigned int uninitialized_var(altsetting);
+		unsigned int altsetting;
 		int intfnum = stream->intfnum;
 
 		/* Isochronous endpoint, select the alternate setting. */