Hi Ard, I love your patch! Perhaps something to improve: [auto build test WARNING on pm/linux-next] [also build test WARNING on arm64/for-next/core arm/for-next soc/for-next v5.9-rc1 next-20200817] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/ACPI-ioremap-avoi... base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next config: i386-randconfig-m021-20200817 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; smatch warnings: drivers/acpi/osl.c:371 acpi_os_map_iomem() error: uninitialized symbol 'virt'. # https://github.com/0day-ci/linux/commit/a34cc34917319aed90ebf9b0fbf414666... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ard-Biesheuvel/ACPI-ioremap-avoid-redundant-rounding-to-OS-page-size/20200817-200603 git checkout a34cc34917319aed90ebf9b0fbf4146666f5f75d vim +/virt +371 drivers/acpi/osl.c 308 309 /** 310 * acpi_os_map_iomem - Get a virtual address for a given physical address range. 311 * @phys: Start of the physical address range to map. 312 * @size: Size of the physical address range to map. 313 * 314 * Look up the given physical address range in the list of existing ACPI memory 315 * mappings. If found, get a reference to it and return a pointer to it (its 316 * virtual address). If not found, map it, add it to that list and return a 317 * pointer to it. 318 * 319 * During early init (when acpi_permanent_mmap has not been set yet) this 320 * routine simply calls __acpi_map_table() to get the job done. 321 */ 322 void __iomem __ref 323 *acpi_os_map_iomem(acpi_physical_address phys, acpi_size size) 324 { 325 struct acpi_ioremap *map; 326 void __iomem *virt; 327 acpi_physical_address pg_off; 328 acpi_size pg_sz; 329 330 if (phys > ULONG_MAX) { 331 printk(KERN_ERR PREFIX "Cannot map memory that high\n"); 332 return NULL; 333 } 334 335 if (!acpi_permanent_mmap) 336 return __acpi_map_table((unsigned long)phys, size); 337 338 mutex_lock(&acpi_ioremap_lock); 339 /* Check if there's a suitable mapping already. */ 340 map = acpi_map_lookup(phys, size); 341 if (map) { 342 map->track.refcount++; 343 goto out; 344 } 345 346 map = kzalloc(sizeof(*map), GFP_KERNEL); 347 if (!map) { 348 mutex_unlock(&acpi_ioremap_lock); 349 return NULL; 350 } 351 352 pg_off = round_down(phys, PAGE_SIZE); 353 pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off; 354 virt = acpi_map(phys, size); 355 if (!virt) { 356 mutex_unlock(&acpi_ioremap_lock); 357 kfree(map); 358 return NULL; 359 } 360 361 INIT_LIST_HEAD(&map->list); 362 map->virt = (void *)((unsigned long)virt & PAGE_MASK); 363 map->phys = pg_off; 364 map->size = pg_sz; 365 map->track.refcount = 1; 366 367 list_add_tail_rcu(&map->list, &acpi_ioremaps); 368 369 out: 370 mutex_unlock(&acpi_ioremap_lock); 372 } 373 EXPORT_SYMBOL_GPL(acpi_os_map_iomem); 374 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org