[sean-jc:x86/formalize_shadow_mmu 29/39] arch/x86/kvm/mmu/mmu.c:3178:15: warning: no previous prototype for function 'mmu_shrink_scan'

[sean-jc:x86/formalize_shadow_mmu 29/39] arch/x86/kvm/mmu/mmu.c:3178:15: warning: no previous prototype for function 'mmu_shrink_scan'

[kernel test robot]

Hi Ben,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://github.com/sean-jc/linux x86/formalize_shadow_mmu
head:   dd395c7174581183cd66020ac5a784bdf2e79cd1
commit: 65d06e1aa5898de35579978883d1d71dad826347 [29/39] KVM: x86/MMU: Cleanup shrinker interface with Shadow MMU
config: x86_64-randconfig-a011-20230313 (https://download.01.org/0day-ci/archive/20230318/202303181408.ZCMIjrIl-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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
        # https://github.com/sean-jc/linux/commit/65d06e1aa5898de35579978883d1d71dad826347
        git remote add sean-jc https://github.com/sean-jc/linux
        git fetch --no-tags sean-jc x86/formalize_shadow_mmu
        git checkout 65d06e1aa5898de35579978883d1d71dad826347
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kvm/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303181408.ZCMIjrIl-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/x86/kvm/mmu/mmu.c:758:1: error: version control conflict marker in file
   <<<<<<< HEAD
   ^
   arch/x86/kvm/mmu/mmu.c:2129:23: error: use of undeclared identifier 'paging64_sync_spte'; did you mean 'paging64_sync_page'?
           context->sync_spte = paging64_sync_spte;
                                ^~~~~~~~~~~~~~~~~~
                                paging64_sync_page
   arch/x86/kvm/mmu/shadow_mmu.h:132:5: note: 'paging64_sync_page' declared here
   int paging64_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
       ^
   arch/x86/kvm/mmu/mmu.c:2136:23: error: use of undeclared identifier 'paging32_sync_spte'; did you mean 'paging32_sync_page'?
           context->sync_spte = paging32_sync_spte;
                                ^~~~~~~~~~~~~~~~~~
                                paging32_sync_page
   arch/x86/kvm/mmu/shadow_mmu.h:131:5: note: 'paging32_sync_page' declared here
   int paging32_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
       ^
   arch/x86/kvm/mmu/mmu.c:2355:24: error: use of undeclared identifier 'ept_sync_spte'; did you mean 'ept_sync_page'?
                   context->sync_spte = ept_sync_spte;
                                        ^~~~~~~~~~~~~
                                        ept_sync_page
   arch/x86/kvm/mmu/shadow_mmu.h:133:5: note: 'ept_sync_page' declared here
   int ept_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
       ^
   arch/x86/kvm/mmu/mmu.c:2576:34: error: variable has incomplete type 'struct kvm_shadow_walk_iterator'
           struct kvm_shadow_walk_iterator iterator;
                                           ^
   arch/x86/kvm/mmu/mmu.c:2576:9: note: forward declaration of 'struct kvm_shadow_walk_iterator'
           struct kvm_shadow_walk_iterator iterator;
                  ^
   arch/x86/kvm/mmu/mmu.c:2584:2: error: implicit declaration of function 'for_each_shadow_entry_using_root' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           for_each_shadow_entry_using_root(vcpu, root_hpa, addr, iterator) {
           ^
>> arch/x86/kvm/mmu/mmu.c:3178:15: warning: no previous prototype for function 'mmu_shrink_scan' [-Wmissing-prototypes]
   unsigned long mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
                 ^
   arch/x86/kvm/mmu/mmu.c:3178:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   unsigned long mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
   ^
   static 
   1 warning and 6 errors generated.


vim +/mmu_shrink_scan +3178 arch/x86/kvm/mmu/mmu.c

  3177	
> 3178	unsigned long mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
  3179	{
  3180		struct kvm *kvm;
  3181		int nr_to_scan = sc->nr_to_scan;
  3182		unsigned long freed = 0;
  3183	
  3184		mutex_lock(&kvm_lock);
  3185	
  3186		list_for_each_entry(kvm, &vm_list, vm_list) {
  3187			/*
  3188			 * Never scan more than sc->nr_to_scan VM instances.
  3189			 * Will not hit this condition practically since we do not try
  3190			 * to shrink more than one VM and it is very unlikely to see
  3191			 * !n_used_mmu_pages so many times.
  3192			 */
  3193			if (!nr_to_scan--)
  3194				break;
  3195	
  3196			/*
  3197			 * n_used_mmu_pages is accessed without holding kvm->mmu_lock
  3198			 * here. We may skip a VM instance errorneosly, but we do not
  3199			 * want to shrink a VM that only started to populate its MMU
  3200			 * anyway.
  3201			 */
  3202			if (!kvm->arch.n_used_mmu_pages &&
  3203			    !kvm_shadow_mmu_has_zapped_obsolete_pages(kvm))
  3204				continue;
  3205	
  3206			freed = kvm_shadow_mmu_shrink_scan(kvm, sc->nr_to_scan);
  3207	
  3208			/*
  3209			 * unfair on small ones
  3210			 * per-vm shrinkers cry out
  3211			 * sadness comes quickly
  3212			 */
  3213			list_move_tail(&kvm->vm_list, &vm_list);
  3214			break;
  3215		}
  3216	
  3217		mutex_unlock(&kvm_lock);
  3218		return freed;
  3219	}
  3220	

-- 
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https://github.com/intel/lkp-tests