[bug report] soundwire: Add IO transfer

[bug report] soundwire: Add IO transfer

[Dan Carpenter]

Hello Vinod Koul,

The patch 9d715fa005eb: "soundwire: Add IO transfer" from Dec 14,
2017, leads to the following static checker warning:

	drivers/soundwire/bus.c:309 sdw_nread()
	info: return a literal instead of 'ret'

drivers/soundwire/bus.c
   297  int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
   298  {
   299          struct sdw_msg msg;
   300          int ret;
   301  
   302          ret = sdw_fill_msg(&msg, slave, addr, count,
   303                          slave->dev_num, SDW_MSG_FLAG_READ, val);
   304          if (ret < 0)
   305                  return ret;
   306  
   307          ret = pm_runtime_get_sync(slave->bus->dev);
   308          if (!ret)
   309                  return ret;

Changing "return ret;" to "return 0;" is more readable, but I mostly
am not sure this is correct.  rpm_resume() has crap comments.  It
sometimes returns negatives, sometimes zero and sometimes one but I have
no idea what it means...  Probably this check should be:

		if (ret <= 0)
			return ret;

(Bugs like this is why the static checker warning exists).

   310  
   311          ret = sdw_transfer(slave->bus, &msg);
   312          pm_runtime_put(slave->bus->dev);
   313  
   314          return ret;
   315  }
   316  EXPORT_SYMBOL(sdw_nread);
   317  
   318  /**
   319   * sdw_nwrite() - Write "n" contiguous SDW Slave registers
   320   * @slave: SDW Slave
   321   * @addr: Register address
   322   * @count: length
   323   * @val: Buffer for values to be read
   324   */
   325  int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
   326  {
   327          struct sdw_msg msg;
   328          int ret;
   329  
   330          ret = sdw_fill_msg(&msg, slave, addr, count,
   331                          slave->dev_num, SDW_MSG_FLAG_WRITE, val);
   332          if (ret < 0)
   333                  return ret;
   334  
   335          ret = pm_runtime_get_sync(slave->bus->dev);
   336          if (!ret)
   337                  return ret;

Same static checker warning here.

   338  
   339          ret = sdw_transfer(slave->bus, &msg);
   340          pm_runtime_put(slave->bus->dev);

regards,
dan carpenter

Re: [bug report] soundwire: Add IO transfer

[Vinod Koul]

On Fri, Jan 05, 2018 at 04:47:05PM +0300, Dan Carpenter wrote:
> Hello Vinod Koul,
> 
> The patch 9d715fa005eb: "soundwire: Add IO transfer" from Dec 14,
> 2017, leads to the following static checker warning:
> 
> 	drivers/soundwire/bus.c:309 sdw_nread()
> 	info: return a literal instead of 'ret'
> 
> drivers/soundwire/bus.c
>    297  int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
>    298  {
>    299          struct sdw_msg msg;
>    300          int ret;
>    301  
>    302          ret = sdw_fill_msg(&msg, slave, addr, count,
>    303                          slave->dev_num, SDW_MSG_FLAG_READ, val);
>    304          if (ret < 0)
>    305                  return ret;
>    306  
>    307          ret = pm_runtime_get_sync(slave->bus->dev);
>    308          if (!ret)
>    309                  return ret;
> 
> Changing "return ret;" to "return 0;" is more readable, but I mostly
> am not sure this is correct.  rpm_resume() has crap comments.  It
> sometimes returns negatives, sometimes zero and sometimes one but I have
> no idea what it means...  Probably this check should be:
> 
> 		if (ret <= 0)
> 			return ret;

That's right we already have a patch for this in our internal code, will send
that out. rpm_resume can return positive values and yes that should be
documented somewhere :)

> 
> (Bugs like this is why the static checker warning exists).
> 
>    310  
>    311          ret = sdw_transfer(slave->bus, &msg);
>    312          pm_runtime_put(slave->bus->dev);
>    313  
>    314          return ret;
>    315  }
>    316  EXPORT_SYMBOL(sdw_nread);
>    317  
>    318  /**
>    319   * sdw_nwrite() - Write "n" contiguous SDW Slave registers
>    320   * @slave: SDW Slave
>    321   * @addr: Register address
>    322   * @count: length
>    323   * @val: Buffer for values to be read
>    324   */
>    325  int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
>    326  {
>    327          struct sdw_msg msg;
>    328          int ret;
>    329  
>    330          ret = sdw_fill_msg(&msg, slave, addr, count,
>    331                          slave->dev_num, SDW_MSG_FLAG_WRITE, val);
>    332          if (ret < 0)
>    333                  return ret;
>    334  
>    335          ret = pm_runtime_get_sync(slave->bus->dev);
>    336          if (!ret)
>    337                  return ret;
> 
> Same static checker warning here.
> 
>    338  
>    339          ret = sdw_transfer(slave->bus, &msg);
>    340          pm_runtime_put(slave->bus->dev);
> 
> regards,
> dan carpenter

-- 
~Vinod