2 files changed, 3 insertions, 37 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index ee9f8bdee755..351da40807c5 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -411,8 +411,6 @@ struct kvm {
         int n_free_mmu_pages;
         struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
         struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
-        int memory_config_version;
-        int busy;
         unsigned long rmap_overflow;
         struct list_head vm_list;
         struct file *filp;
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 9dffbbea46a7..8da13a462e3c 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -679,7 +679,6 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
         unsigned long i;
         struct kvm_memory_slot *memslot;
         struct kvm_memory_slot old, new;
-        int memory_config_version;
 
         r = -EINVAL;
         /* General sanity checks */
@@ -699,10 +698,8 @@ static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
         if (!npages)
                 mem->flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
 
-raced:
         mutex_lock(&kvm->lock);
 
-        memory_config_version = kvm->memory_config_version;
         new = old = *memslot;
 
         new.base_gfn = base_gfn;
@@ -725,11 +722,6 @@ raced:
                       (base_gfn >= s->base_gfn + s->npages)))
                         goto out_unlock;
         }
-        /*
-         * Do memory allocations outside lock.  memory_config_version will
-         * detect any races.
-         */
-        mutex_unlock(&kvm->lock);
 
         /* Deallocate if slot is being removed */
         if (!npages)
@@ -746,14 +738,14 @@ raced:
                 new.phys_mem = vmalloc(npages * sizeof(struct page *));
 
                 if (!new.phys_mem)
-                        goto out_free;
+                        goto out_unlock;
 
                 memset(new.phys_mem, 0, npages * sizeof(struct page *));
                 for (i = 0; i < npages; ++i) {
                         new.phys_mem[i] = alloc_page(GFP_HIGHUSER
                                                      | __GFP_ZERO);
                         if (!new.phys_mem[i])
-                                goto out_free;
+                                goto out_unlock;
                         set_page_private(new.phys_mem[i],0);
                 }
         }
@@ -764,27 +756,14 @@ raced:
 
                 new.dirty_bitmap = vmalloc(dirty_bytes);
                 if (!new.dirty_bitmap)
-                        goto out_free;
+                        goto out_unlock;
                 memset(new.dirty_bitmap, 0, dirty_bytes);
         }
 
-        mutex_lock(&kvm->lock);
-
-        if (memory_config_version != kvm->memory_config_version) {
-                mutex_unlock(&kvm->lock);
-                kvm_free_physmem_slot(&new, &old);
-                goto raced;
-        }
-
-        r = -EAGAIN;
-        if (kvm->busy)
-                goto out_unlock;
-
         if (mem->slot >= kvm->nmemslots)
                 kvm->nmemslots = mem->slot + 1;
 
         *memslot = new;
-        ++kvm->memory_config_version;
 
         kvm_mmu_slot_remove_write_access(kvm, mem->slot);
         kvm_flush_remote_tlbs(kvm);
@@ -796,7 +775,6 @@ raced:
 
 out_unlock:
         mutex_unlock(&kvm->lock);
-out_free:
         kvm_free_physmem_slot(&new, &old);
 out:
         return r;
@@ -815,12 +793,6 @@ static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 
         mutex_lock(&kvm->lock);
 
-        /*
-         * Prevent changes to guest memory configuration even while the lock
-         * is not taken.
-         */
-        ++kvm->busy;
-        mutex_unlock(&kvm->lock);
         r = -EINVAL;
         if (log->slot >= KVM_MEMORY_SLOTS)
                 goto out;
@@ -841,18 +813,14 @@ static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 
         /* If nothing is dirty, don't bother messing with page tables. */
         if (any) {
-                mutex_lock(&kvm->lock);
                 kvm_mmu_slot_remove_write_access(kvm, log->slot);
                 kvm_flush_remote_tlbs(kvm);
                 memset(memslot->dirty_bitmap, 0, n);
-                mutex_unlock(&kvm->lock);
         }
 
         r = 0;
 
 out:
-        mutex_lock(&kvm->lock);
-        --kvm->busy;
         mutex_unlock(&kvm->lock);
         return r;
 }