Hi Hannes,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mkp-scsi/for-next]
[also build test WARNING on scsi/for-next v5.7-rc7 next-20200529]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Hannes-Reinecke/scsi-use-xarray-for-devices-and-targets/20200527-231824
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next
config: x86_64-randconfig-m001-20200529 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-13) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

New smatch warnings:
drivers/scsi/scsi_sysfs.c:1625 scsi_sysfs_device_initialize() warn: always true condition '(sdev->lun_idx != -1) => (0-u32max != u64max)'

Old smatch warnings:
drivers/scsi/scsi_sysfs.c:437 scsi_device_dev_release_usercontext() error: potentially dereferencing uninitialized 'sdev'.

vim +1625 drivers/scsi/scsi_sysfs.c

  1592	
  1593	void scsi_sysfs_device_initialize(struct scsi_device *sdev)
  1594	{
  1595		unsigned long flags;
  1596		struct Scsi_Host *shost = sdev->host;
  1597		struct scsi_target  *starget = sdev->sdev_target;
  1598	
  1599		device_initialize(&sdev->sdev_gendev);
  1600		sdev->sdev_gendev.bus = &scsi_bus_type;
  1601		sdev->sdev_gendev.type = &scsi_dev_type;
  1602		dev_set_name(&sdev->sdev_gendev, "%d:%d:%d:%llu",
  1603			     sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);
  1604	
  1605		device_initialize(&sdev->sdev_dev);
  1606		sdev->sdev_dev.parent = get_device(&sdev->sdev_gendev);
  1607		sdev->sdev_dev.class = &sdev_class;
  1608		dev_set_name(&sdev->sdev_dev, "%d:%d:%d:%llu",
  1609			     sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);
  1610		/*
  1611		 * Get a default scsi_level from the target (derived from sibling
  1612		 * devices).  This is the best we can do for guessing how to set
  1613		 * sdev->lun_in_cdb for the initial INQUIRY command.  For LUN 0 the
  1614		 * setting doesn't matter, because all the bits are zero anyway.
  1615		 * But it does matter for higher LUNs.
  1616		 */
  1617		sdev->scsi_level = starget->scsi_level;
  1618		if (sdev->scsi_level <= SCSI_2 &&
  1619				sdev->scsi_level != SCSI_UNKNOWN &&
  1620				!shost->no_scsi2_lun_in_cdb)
  1621			sdev->lun_in_cdb = 1;
  1622	
  1623		transport_setup_device(&sdev->sdev_gendev);
  1624		spin_lock_irqsave(shost->host_lock, flags);
> 1625		if (sdev->lun_idx != (unsigned long)-1)
  1626			WARN_ON(!xa_insert(&starget->devices, sdev->lun_idx,
  1627					   sdev, GFP_KERNEL));
  1628		else {
  1629			struct xa_limit scsi_lun_limit = {
  1630				.min = 256,
  1631				.max = UINT_MAX,
  1632			};
  1633			WARN_ON(!xa_alloc(&starget->devices, &sdev->lun_idx,
  1634					  sdev, scsi_lun_limit, GFP_KERNEL));
  1635		}
  1636		list_add_tail(&sdev->siblings, &shost->__devices);
  1637		spin_unlock_irqrestore(shost->host_lock, flags);
  1638		/*
  1639		 * device can now only be removed via __scsi_remove_device() so hold
  1640		 * the target.  Target will be held in CREATED state until something
  1641		 * beneath it becomes visible (in which case it moves to RUNNING)
  1642		 */
  1643		kref_get(&starget->reap_ref);
  1644	}
  1645	

---
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