[PATCH v2 1/7] drm/panthor: Add support for atomic page table updates

[kernel test robot]

Hi Caterina,

kernel test robot noticed the following build warnings:

[auto build test WARNING on drm-xe/drm-xe-next]
[also build test WARNING on linus/master v6.16-rc4 next-20250703]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Caterina-Shablia/drm-gpuvm-Kill-drm_gpuva_init/20250704-002914
base:   https://gitlab.freedesktop.org/drm/xe/kernel.git drm-xe-next
patch link:    https://lore.kernel.org/r/20250703152908.16702-3-caterina.shablia%40collabora.com
patch subject: [PATCH v2 1/7] drm/panthor: Add support for atomic page table updates
config: x86_64-buildonly-randconfig-004-20250704 (https://download.01.org/0day-ci/archive/20250704/202507041635.WyDu3TQ1-lkp@intel.com/config)
compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250704/202507041635.WyDu3TQ1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507041635.WyDu3TQ1-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/panthor/panthor_mmu.c:1685:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
    1685 |         if (vm->as.id >= 0) {
         |             ^~~~~~~~~~~~~~
   drivers/gpu/drm/panthor/panthor_mmu.c:1691:9: note: uninitialized use occurs here
    1691 |         return ret;
         |                ^~~
   drivers/gpu/drm/panthor/panthor_mmu.c:1685:2: note: remove the 'if' if its condition is always true
    1685 |         if (vm->as.id >= 0) {
         |         ^~~~~~~~~~~~~~~~~~~
   drivers/gpu/drm/panthor/panthor_mmu.c:1679:9: note: initialize the variable 'ret' to silence this warning
    1679 |         int ret;
         |                ^
         |                 = 0
   1 warning generated.


vim +1685 drivers/gpu/drm/panthor/panthor_mmu.c

  1675	
  1676	static int panthor_vm_lock_region(struct panthor_vm *vm, u64 start, u64 size)
  1677	{
  1678		struct panthor_device *ptdev = vm->ptdev;
  1679		int ret;
  1680	
  1681		mutex_lock(&ptdev->mmu->as.slots_lock);
  1682		drm_WARN_ON(&ptdev->base, vm->locked_region.start || vm->locked_region.size);
  1683		vm->locked_region.start = start;
  1684		vm->locked_region.size = size;
> 1685		if (vm->as.id >= 0) {
  1686			lock_region(ptdev, vm->as.id, start, size);
  1687			ret = wait_ready(ptdev, vm->as.id);
  1688		}
  1689		mutex_unlock(&ptdev->mmu->as.slots_lock);
  1690	
  1691		return ret;
  1692	}
  1693	

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