[09/17] soundwire: stream: remove unnecessary variable initializations
diff mbox series

Message ID 20190806005522.22642-10-pierre-louis.bossart@linux.intel.com
State New
Headers show
Series
  • soundwire: fixes for 5.4
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Commit Message

Pierre-Louis Bossart Aug. 6, 2019, 12:55 a.m. UTC
A number of variables don't need to be initialized.

In a couple of cases where we loop on a list of runtimes, the code
handling of the 'bus' variable leads to warnings that it may not be
initialized. Add a specific error case to trap such cases.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/stream.c | 64 ++++++++++++++++++++++----------------
 1 file changed, 38 insertions(+), 26 deletions(-)

Comments

Cezary Rojewski Aug. 6, 2019, 3:31 p.m. UTC | #1
On 2019-08-06 02:55, Pierre-Louis Bossart wrote:
> @@ -1493,6 +1493,11 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
>   		}
>   	}
>   
> +	if (!bus) {
> +		pr_err("Configuration error in %s\n", __func__);
> +		return -EINVAL;
> +	}
> +

This should probably be located in separate path - not at all an 
initialization removal.

> @@ -1573,6 +1578,11 @@ static int _sdw_enable_stream(struct sdw_stream_runtime *stream)
>   		}
>   	}
>   
> +	if (!bus) {
> +		pr_err("Configuration error in %s\n", __func__);
> +		return -EINVAL;
> +	}
> +

Same here.

> @@ -1639,13 +1650,14 @@ static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
>   
>   	ret = do_bank_switch(stream);
>   	if (ret < 0) {
> -		dev_err(bus->dev, "Bank switch failed: %d\n", ret);
> +		pr_err("Bank switch failed: %d\n", ret);
>   		return ret;
>   	}

Here too.

I might have missed something though I bet you got my point.
Pierre-Louis Bossart Aug. 6, 2019, 3:39 p.m. UTC | #2
On 8/6/19 10:31 AM, Cezary Rojewski wrote:
> On 2019-08-06 02:55, Pierre-Louis Bossart wrote:
>> @@ -1493,6 +1493,11 @@ static int _sdw_prepare_stream(struct 
>> sdw_stream_runtime *stream)
>>           }
>>       }
>> +    if (!bus) {
>> +        pr_err("Configuration error in %s\n", __func__);
>> +        return -EINVAL;
>> +    }
>> +
> 
> This should probably be located in separate path - not at all an 
> initialization removal.

It's a consequence of the initialization removal: because we are 
removing the default init, there is a risk that the loop just before do 
not set it, so it's required to trap the case where the variable in not 
initialized.

> 
>> @@ -1573,6 +1578,11 @@ static int _sdw_enable_stream(struct 
>> sdw_stream_runtime *stream)
>>           }
>>       }
>> +    if (!bus) {
>> +        pr_err("Configuration error in %s\n", __func__);
>> +        return -EINVAL;
>> +    }
>> +
> 
> Same here.

same reply

> 
>> @@ -1639,13 +1650,14 @@ static int _sdw_disable_stream(struct 
>> sdw_stream_runtime *stream)
>>       ret = do_bank_switch(stream);
>>       if (ret < 0) {
>> -        dev_err(bus->dev, "Bank switch failed: %d\n", ret);
>> +        pr_err("Bank switch failed: %d\n", ret);
>>           return ret;
>>       }
> 
> Here too.

no, same thing, the bus variable is initialized in loops so tools will 
report a possible path where bus->dev is an invalid dereference.

> I might have missed something though I bet you got my point.

Patch
diff mbox series

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 75b9ad1fb1a6..8d6c13528b68 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -369,7 +369,7 @@  static int sdw_enable_disable_master_ports(struct sdw_master_runtime *m_rt,
 static int sdw_enable_disable_ports(struct sdw_master_runtime *m_rt, bool en)
 {
 	struct sdw_port_runtime *s_port, *m_port;
-	struct sdw_slave_runtime *s_rt = NULL;
+	struct sdw_slave_runtime *s_rt;
 	int ret = 0;
 
 	/* Enable/Disable Slave port(s) */
@@ -417,7 +417,7 @@  static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,
 				       struct sdw_port_runtime *p_rt,
 				       bool prep)
 {
-	struct completion *port_ready = NULL;
+	struct completion *port_ready;
 	struct sdw_dpn_prop *dpn_prop;
 	struct sdw_prepare_ch prep_ch;
 	unsigned int time_left;
@@ -537,7 +537,7 @@  static int sdw_prep_deprep_master_ports(struct sdw_master_runtime *m_rt,
  */
 static int sdw_prep_deprep_ports(struct sdw_master_runtime *m_rt, bool prep)
 {
-	struct sdw_slave_runtime *s_rt = NULL;
+	struct sdw_slave_runtime *s_rt;
 	struct sdw_port_runtime *p_rt;
 	int ret = 0;
 
@@ -605,7 +605,7 @@  static int sdw_notify_config(struct sdw_master_runtime *m_rt)
  */
 static int sdw_program_params(struct sdw_bus *bus)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	int ret = 0;
 
 	list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {
@@ -642,8 +642,8 @@  static int sdw_bank_switch(struct sdw_bus *bus, int m_rt_count)
 	int col_index, row_index;
 	bool multi_link;
 	struct sdw_msg *wr_msg;
-	u8 *wbuf = NULL;
-	int ret = 0;
+	u8 *wbuf;
+	int ret;
 	u16 addr;
 
 	wr_msg = kzalloc(sizeof(*wr_msg), GFP_KERNEL);
@@ -741,9 +741,9 @@  static int sdw_ml_sync_bank_switch(struct sdw_bus *bus)
 
 static int do_bank_switch(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	const struct sdw_master_ops *ops;
-	struct sdw_bus *bus = NULL;
+	struct sdw_bus *bus;
 	bool multi_link = false;
 	int ret = 0;
 
@@ -886,7 +886,7 @@  static struct sdw_master_runtime
 *sdw_find_master_rt(struct sdw_bus *bus,
 		    struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 
 	/* Retrieve Bus handle if already available */
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
@@ -955,7 +955,7 @@  static struct sdw_slave_runtime
 		    struct sdw_stream_config *stream_config,
 		    struct sdw_stream_runtime *stream)
 {
-	struct sdw_slave_runtime *s_rt = NULL;
+	struct sdw_slave_runtime *s_rt;
 
 	s_rt = kzalloc(sizeof(*s_rt), GFP_KERNEL);
 	if (!s_rt)
@@ -1261,7 +1261,7 @@  int sdw_stream_add_master(struct sdw_bus *bus,
 			  unsigned int num_ports,
 			  struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	int ret;
 
 	mutex_lock(&bus->bus_lock);
@@ -1428,7 +1428,7 @@  struct sdw_dpn_prop *sdw_get_slave_dpn_prop(struct sdw_slave *slave,
  */
 static void sdw_acquire_bus_lock(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	struct sdw_bus *bus = NULL;
 
 	/* Iterate for all Master(s) in Master list */
@@ -1462,9 +1462,9 @@  static void sdw_release_bus_lock(struct sdw_stream_runtime *stream)
 
 static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	struct sdw_bus *bus = NULL;
-	struct sdw_master_prop *prop = NULL;
+	struct sdw_master_prop *prop;
 	struct sdw_bus_params params;
 	int ret;
 
@@ -1493,6 +1493,11 @@  static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
 		}
 	}
 
+	if (!bus) {
+		pr_err("Configuration error in %s\n", __func__);
+		return -EINVAL;
+	}
+
 	ret = do_bank_switch(stream);
 	if (ret < 0) {
 		dev_err(bus->dev, "Bank switch failed: %d\n", ret);
@@ -1549,7 +1554,7 @@  EXPORT_SYMBOL(sdw_prepare_stream);
 
 static int _sdw_enable_stream(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
+	struct sdw_master_runtime *m_rt;
 	struct sdw_bus *bus = NULL;
 	int ret;
 
@@ -1573,6 +1578,11 @@  static int _sdw_enable_stream(struct sdw_stream_runtime *stream)
 		}
 	}
 
+	if (!bus) {
+		pr_err("Configuration error in %s\n", __func__);
+		return -EINVAL;
+	}
+
 	ret = do_bank_switch(stream);
 	if (ret < 0) {
 		dev_err(bus->dev, "Bank switch failed: %d\n", ret);
@@ -1592,7 +1602,7 @@  static int _sdw_enable_stream(struct sdw_stream_runtime *stream)
  */
 int sdw_enable_stream(struct sdw_stream_runtime *stream)
 {
-	int ret = 0;
+	int ret;
 
 	if (!stream) {
 		pr_err("SoundWire: Handle not found for stream\n");
@@ -1612,12 +1622,12 @@  EXPORT_SYMBOL(sdw_enable_stream);
 
 static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
-	struct sdw_bus *bus = NULL;
+	struct sdw_master_runtime *m_rt;
 	int ret;
 
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
-		bus = m_rt->bus;
+		struct sdw_bus *bus = m_rt->bus;
+
 		/* Disable port(s) */
 		ret = sdw_enable_disable_ports(m_rt, false);
 		if (ret < 0) {
@@ -1628,7 +1638,8 @@  static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
 	stream->state = SDW_STREAM_DISABLED;
 
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
-		bus = m_rt->bus;
+		struct sdw_bus *bus = m_rt->bus;
+
 		/* Program params */
 		ret = sdw_program_params(bus);
 		if (ret < 0) {
@@ -1639,13 +1650,14 @@  static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
 
 	ret = do_bank_switch(stream);
 	if (ret < 0) {
-		dev_err(bus->dev, "Bank switch failed: %d\n", ret);
+		pr_err("Bank switch failed: %d\n", ret);
 		return ret;
 	}
 
 	/* make sure alternate bank (previous current) is also disabled */
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
-		bus = m_rt->bus;
+		struct sdw_bus *bus = m_rt->bus;
+
 		/* Disable port(s) */
 		ret = sdw_enable_disable_ports(m_rt, false);
 		if (ret < 0) {
@@ -1666,7 +1678,7 @@  static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
  */
 int sdw_disable_stream(struct sdw_stream_runtime *stream)
 {
-	int ret = 0;
+	int ret;
 
 	if (!stream) {
 		pr_err("SoundWire: Handle not found for stream\n");
@@ -1686,8 +1698,8 @@  EXPORT_SYMBOL(sdw_disable_stream);
 
 static int _sdw_deprepare_stream(struct sdw_stream_runtime *stream)
 {
-	struct sdw_master_runtime *m_rt = NULL;
-	struct sdw_bus *bus = NULL;
+	struct sdw_master_runtime *m_rt;
+	struct sdw_bus *bus;
 	int ret = 0;
 
 	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
@@ -1725,7 +1737,7 @@  static int _sdw_deprepare_stream(struct sdw_stream_runtime *stream)
  */
 int sdw_deprepare_stream(struct sdw_stream_runtime *stream)
 {
-	int ret = 0;
+	int ret;
 
 	if (!stream) {
 		pr_err("SoundWire: Handle not found for stream\n");