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-20200526] [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-lkp (attached as .config) compiler: gcc-8 (Debian 8.3.0-6) 8.3.0 reproduce (this is a W=1 build): # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot All warnings (new ones prefixed by >>, old ones prefixed by <<): >> drivers/scsi/scsi.c:638:21: warning: no previous prototype for '__scsi_target_lookup' [-Wmissing-prototypes] struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, ^~~~~~~~~~~~~~~~~~~~ vim +/__scsi_target_lookup +638 drivers/scsi/scsi.c 630 631 /** 632 * __scsi_target_lookup - find a target based on channel and target id 633 * @shost: SCSI host pointer 634 * @channel: channel number of the target 635 * @id: ID of the target 636 * 637 */ > 638 struct scsi_target *__scsi_target_lookup(struct Scsi_Host *shost, 639 u16 channel, u16 id) 640 { 641 return xa_load(&shost->__targets, (channel << 16) | id); 642 } 643 EXPORT_SYMBOL(__scsi_target_lookup); 644 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org