Hi Henry, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on mkp-scsi/for-next] [also build test WARNING on scsi/for-next v5.8-rc1 next-20200618] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Henry-Willard/scsi-target-tcmu-C... base: https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next config: xtensa-allyesconfig (attached as .config) compiler: xtensa-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): In file included from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/preempt.h:11, from include/linux/spinlock.h:51, from drivers/target/target_core_user.c:9: include/linux/scatterlist.h: In function 'sg_set_buf': arch/xtensa/include/asm/page.h:193:9: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 193 | ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) | ^~ include/linux/compiler.h:78:42: note: in definition of macro 'unlikely' 78 | # define unlikely(x) __builtin_expect(!!(x), 0) | ^ include/linux/scatterlist.h:143:2: note: in expansion of macro 'BUG_ON' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~ arch/xtensa/include/asm/page.h:201:32: note: in expansion of macro 'pfn_valid' 201 | #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) | ^~~~~~~~~ include/linux/scatterlist.h:143:10: note: in expansion of macro 'virt_addr_valid' 143 | BUG_ON(!virt_addr_valid(buf)); | ^~~~~~~~~~~~~~~ In file included from ./arch/xtensa/include/generated/asm/bug.h:1, from include/linux/bug.h:5, from include/linux/thread_info.h:12, from include/asm-generic/preempt.h:5, from ./arch/xtensa/include/generated/asm/preempt.h:1, from include/linux/preempt.h:78, from include/linux/spinlock.h:51, from drivers/target/target_core_user.c:9: include/linux/dma-mapping.h: In function 'dma_map_resource': arch/xtensa/include/asm/page.h:193:9: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 193 | ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) | ^~ include/asm-generic/bug.h:144:27: note: in definition of macro 'WARN_ON_ONCE' 144 | int __ret_warn_once = !!(condition); | ^~~~~~~~~ include/linux/dma-mapping.h:352:19: note: in expansion of macro 'pfn_valid' 352 | if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr)))) | ^~~~~~~~~ In file included from include/linux/mm_types_task.h:16, from include/linux/mm_types.h:5, from include/linux/mmzone.h:21, from include/linux/gfp.h:6, from include/linux/umh.h:4, from include/linux/kmod.h:9, from include/linux/module.h:16, from drivers/target/target_core_user.c:10: drivers/target/target_core_user.c: In function 'tcmu_flush_dcache_range': arch/xtensa/include/asm/page.h:193:9: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 193 | ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr) | ^~ arch/xtensa/include/asm/page.h:201:32: note: in expansion of macro 'pfn_valid' 201 | #define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) | ^~~~~~~~~ drivers/target/target_core_user.c:605:7: note: in expansion of macro 'virt_addr_valid' 605 | if (virt_addr_valid(start)) | ^~~~~~~~~~~~~~~ >> drivers/target/target_core_user.c:600:15: warning: variable 'pg' set but not used [-Wunused-but-set-variable] 600 | struct page *pg; | ^~ vim +/pg +600 drivers/target/target_core_user.c 595 596 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size) 597 { 598 unsigned long offset = offset_in_page(vaddr); 599 void *start = vaddr - offset; > 600 struct page *pg; 601 602 size = round_up(size+offset, PAGE_SIZE); 603 604 while (size) { 605 if (virt_addr_valid(start)) 606 pg = virt_to_page(start); 607 else if (is_vmalloc_addr(start)) 608 pg = vmalloc_to_page(start); 609 else 610 break; 611 612 flush_dcache_page(pg); 613 start += PAGE_SIZE; 614 size -= PAGE_SIZE; 615 } 616 } 617 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org