Staging: iio/dds: double locking bugs

This is a static checker patch and I don't have this hardware.

This code is unusual because while I've often seen a double lock, this
is the first time I've seen code that takes a lock 11 times in a row.  I
feel like I must have missed something.  But I've looked very carefully
I don't see any way the original code is correct.  Does spi_sync()
somehow release the lock in a way that I can't see?  Even if it does,
the locking would still be wrong.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/dds/ad9832.c

@@ -166,8 +166,6 @@ static void ad9832_init(struct ad9832_state *st)
 
 	config = 0x3 << 14;
 
-	mutex_lock(&st->lock);
-
 	xfer.len = 2;
 	xfer.tx_buf = &config;
 

drivers/staging/iio/dds/ad9852.c

@@ -86,7 +86,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 3;
 	xfer.tx_buf = &config->phajst1[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -96,7 +95,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 6;
 	xfer.tx_buf = &config->fretun1[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -106,7 +104,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 6;
 	xfer.tx_buf = &config->fretun2[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -116,7 +113,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 6;
 	xfer.tx_buf = &config->dltafre[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -126,7 +122,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->updtclk[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -136,7 +131,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 4;
 	xfer.tx_buf = &config->ramprat[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -146,7 +140,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->control[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -156,7 +149,6 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 3;
 	xfer.tx_buf = &config->outpskm[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -166,16 +158,15 @@ static ssize_t ad9852_set_parameter(struct device *dev,
 
 	xfer.len = 2;
 	xfer.tx_buf = &config->outpskr[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 3;
 	xfer.tx_buf = &config->daccntl[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);

drivers/staging/iio/dds/ad9910.c

@@ -138,7 +138,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->ioupd[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -148,7 +147,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->ftw[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -158,7 +156,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 3;
 	xfer.tx_buf = &config->pow[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -168,7 +165,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->asf[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -178,7 +174,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->multc[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -188,7 +183,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 9;
 	xfer.tx_buf = &config->dig_rampl[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -198,7 +192,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 9;
 	xfer.tx_buf = &config->dig_ramps[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -208,7 +201,6 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->dig_rampr[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -218,25 +210,24 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep0[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep1[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep2[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -245,43 +236,42 @@ static ssize_t ad9910_set_parameter(struct device *dev,
 		goto error_ret;
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep3[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep4[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep5[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep6[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
 	ret = spi_sync(st->sdev, &msg);
 	if (ret)
 		goto error_ret;
+
 	xfer.len = 9;
 	xfer.tx_buf = &config->sin_tonep7[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -326,8 +316,6 @@ static void ad9910_init(struct ad9910_state *st)
 	cfr[3] = TX_ENA | PDCLK_INV | PDCLK_ENB;
 	cfr[4] = PARA_ENA;
 
-	mutex_lock(&st->lock);
-
 	xfer.len = 5;
 	xfer.tx_buf = 𝔠
 
@@ -343,8 +331,6 @@ static void ad9910_init(struct ad9910_state *st)
 	cfr[3] = REFCLK_RST | REFCLK_BYP;
 	cfr[4] = 0;
 
-	mutex_lock(&st->lock);
-
 	xfer.len = 5;
 	xfer.tx_buf = 𝔠
 

drivers/staging/iio/dds/ad9951.c

@@ -79,7 +79,6 @@ static ssize_t ad9951_set_parameter(struct device *dev,
 
 	xfer.len = 2;
 	xfer.tx_buf = &config->arr[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -89,7 +88,6 @@ static ssize_t ad9951_set_parameter(struct device *dev,
 
 	xfer.len = 5;
 	xfer.tx_buf = &config->ftw0[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -99,7 +97,6 @@ static ssize_t ad9951_set_parameter(struct device *dev,
 
 	xfer.len = 3;
 	xfer.tx_buf = &config->ftw1[0];
-	mutex_lock(&st->lock);
 
 	spi_message_init(&msg);
 	spi_message_add_tail(&xfer, &msg);
@@ -143,8 +140,6 @@ static void ad9951_init(struct ad9951_state *st)
 	cfr[2] = HSPD_SYNC;
 	cfr[3] = 0;
 
-	mutex_lock(&st->lock);
-
 	xfer.len = 4;
 	xfer.tx_buf = 𝔠