re: libata: check zero power ready status for ZPODD

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Aaron Lu,

The patch 3dc67440d99b: "libata: check zero power ready status for
ZPODD" from Jan 15, 2013, leads to the following static checker
warning:

	drivers/ata/libata-zpodd.c:97 zpready()
	error: uninitialized symbol 'sense_key'.

drivers/ata/libata-zpodd.c
    88  /* Test if ODD is zero power ready by sense code */
    89  static bool zpready(struct ata_device *dev)
    90  {
    91          u8 sense_key, *sense_buf;
    92          unsigned int ret, asc, ascq, add_len;
    93          struct zpodd *zpodd = dev->zpodd;
    94  
    95          ret = atapi_eh_tur(dev, &sense_key);
    96  
    97          if (!ret || sense_key != NOT_READY)
    98                  return false;

It's not clear what is going on here.  atapi_eh_tur() returns 0 on
success or a bit mask on error.  If the AC_ERR_DEV (which is BIT(0)) bit
is set and no other bits then we set "&sense_key" otherwise it is
uninitialized.

So maybe the test should be:

	if (ret != AC_ERR_DEV || sense_key != NOT_READY)
		return false;

That would silence the uninitialized variable warning but it's sort of
weird.  You would normall expect to return for errors and continue if
ret were zero.

	if (ret && !(ret == AC_ERR_DEV && ...

    99  
   100          sense_buf = dev->link->ap->sector_buf;
   101          ret = atapi_eh_request_sense(dev, sense_buf, sense_key);
   102          if (ret)
   103                  return false;

regards,
dan carpenter