netdev - [PATCH 15/26] [media] tuners: i2c: reduce stack usage for tuner_i2c_xfer

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Date:   Thu,  2 Mar 2017 17:38:23 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     kasan-dev@...glegroups.com
Cc:     Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-wireless@...r.kernel.org,
        kernel-build-reports@...ts.linaro.org,
        "David S . Miller" <davem@...emloft.net>,
        Arnd Bergmann <arnd@...db.de>
Subject: [PATCH 15/26] [media] tuners: i2c: reduce stack usage for tuner_i2c_xfer_*

When CONFIG_KASAN is enabled, we see very large stack usage in some
functions, e.g.:

drivers/media/tuners/tda8290.c: In function 'tda8290_set_params':
drivers/media/tuners/tda8290.c:310:1: warning: the frame size of 3184 bytes is larger than 1024 bytes [-Wframe-larger-than=]
drivers/media/tuners/tda8290.c: In function 'tda829x_probe':
drivers/media/tuners/tda8290.c:878:1: warning: the frame size of 1088 bytes is larger than 1024 bytes [-Wframe-larger-than=]

By annotating the helpers as noinline_for_kasan, we can easily avoid this.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/media/tuners/tuner-i2c.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/media/tuners/tuner-i2c.h b/drivers/media/tuners/tuner-i2c.h
index bda67a5a76f2..c8970299799c 100644
--- a/drivers/media/tuners/tuner-i2c.h
+++ b/drivers/media/tuners/tuner-i2c.h
@@ -33,8 +33,8 @@ struct tuner_i2c_props {
 	char *name;
 };
 
-static inline int tuner_i2c_xfer_send(struct tuner_i2c_props *props,
-				      unsigned char *buf, int len)
+static noinline_for_kasan int
+tuner_i2c_xfer_send(struct tuner_i2c_props *props, unsigned char *buf, int len)
 {
 	struct i2c_msg msg = { .addr = props->addr, .flags = 0,
 			       .buf = buf, .len = len };
@@ -43,8 +43,8 @@ static inline int tuner_i2c_xfer_send(struct tuner_i2c_props *props,
 	return (ret == 1) ? len : ret;
 }
 
-static inline int tuner_i2c_xfer_recv(struct tuner_i2c_props *props,
-				      unsigned char *buf, int len)
+static noinline_for_kasan int
+tuner_i2c_xfer_recv(struct tuner_i2c_props *props, unsigned char *buf, int len)
 {
 	struct i2c_msg msg = { .addr = props->addr, .flags = I2C_M_RD,
 			       .buf = buf, .len = len };
@@ -53,9 +53,10 @@ static inline int tuner_i2c_xfer_recv(struct tuner_i2c_props *props,
 	return (ret == 1) ? len : ret;
 }
 
-static inline int tuner_i2c_xfer_send_recv(struct tuner_i2c_props *props,
-					   unsigned char *obuf, int olen,
-					   unsigned char *ibuf, int ilen)
+static noinline_for_kasan int
+tuner_i2c_xfer_send_recv(struct tuner_i2c_props *props,
+			 unsigned char *obuf, int olen,
+			 unsigned char *ibuf, int ilen)
 {
 	struct i2c_msg msg[2] = { { .addr = props->addr, .flags = 0,
 				    .buf = obuf, .len = olen },
-- 
2.9.0