From 070ed82e32020dd9cc1ab3b5790b6b7d3f788e30 Mon Sep 17 00:00:00 2001 From: Sakari Ailus Date: Wed, 16 Aug 2017 03:28:16 -0400 Subject: [PATCH] media: et8ek8: Decrease stack usage MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The et8ek8 driver combines I²C register writes to a single array that it passes to i2c_transfer(). The maximum number of writes is 48 at once, decrease it to 8 and make more transfers if needed. Signed-off-by: Sakari Ailus Tested-by: Pavel Machek Signed-off-by: Mauro Carvalho Chehab --- drivers/media/i2c/et8ek8/et8ek8_driver.c | 26 ++++++++++++++++-------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/media/i2c/et8ek8/et8ek8_driver.c b/drivers/media/i2c/et8ek8/et8ek8_driver.c index f39f5179dd95..c14f0fd6ded3 100644 --- a/drivers/media/i2c/et8ek8/et8ek8_driver.c +++ b/drivers/media/i2c/et8ek8/et8ek8_driver.c @@ -43,7 +43,7 @@ #define ET8EK8_NAME "et8ek8" #define ET8EK8_PRIV_MEM_SIZE 128 -#define ET8EK8_MAX_MSG 48 +#define ET8EK8_MAX_MSG 8 struct et8ek8_sensor { struct v4l2_subdev subdev; @@ -220,7 +220,8 @@ static void et8ek8_i2c_create_msg(struct i2c_client *client, u16 len, u16 reg, /* * A buffered write method that puts the wanted register write - * commands in a message list and passes the list to the i2c framework + * commands in smaller number of message lists and passes the lists to + * the i2c framework */ static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client, const struct et8ek8_reg *wnext, @@ -231,11 +232,7 @@ static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client, int wcnt = 0; u16 reg, data_length; u32 val; - - if (WARN_ONCE(cnt > ET8EK8_MAX_MSG, - ET8EK8_NAME ": %s: too many messages.\n", __func__)) { - return -EINVAL; - } + int rval; /* Create new write messages for all writes */ while (wcnt < cnt) { @@ -249,10 +246,21 @@ static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client, /* Update write count */ wcnt++; + + if (wcnt < ET8EK8_MAX_MSG) + continue; + + rval = i2c_transfer(client->adapter, msg, wcnt); + if (rval < 0) + return rval; + + cnt -= wcnt; + wcnt = 0; } - /* Now we send everything ... */ - return i2c_transfer(client->adapter, msg, wcnt); + rval = i2c_transfer(client->adapter, msg, wcnt); + + return rval < 0 ? rval : 0; } /* -- 2.25.1