Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0d8d2bd4f20c8a2a254b4fe3bc114f12214a6d73
Commit:     0d8d2bd4f20c8a2a254b4fe3bc114f12214a6d73
Parent:     1747fb71fd7c9389696e91f354d2f841b5c85790
Author:     Laurent Vivier <[EMAIL PROTECTED]>
AuthorDate: Thu Aug 30 14:56:21 2007 +0200
Committer:  Avi Kivity <[EMAIL PROTECTED]>
CommitDate: Sat Oct 13 10:18:27 2007 +0200

    KVM: Simplify memory allocation
    
    The mutex->splinlock convertion alllows us to make some code 
simplifications.
    As we can keep the lock longer, we don't have to release it and then
    have to check if the environment has not been modified before re-taking it. 
We
    can remove kvm->busy and kvm->memory_config_version.
    
    Signed-off-by: Laurent Vivier <[EMAIL PROTECTED]>
    Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
---
 drivers/kvm/kvm.h      |    2 --
 drivers/kvm/kvm_main.c |   38 +++-----------------------------------
 2 files changed, 3 insertions(+), 37 deletions(-)

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index ee9f8bd..351da40 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 9dffbbe..8da13a4 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;
 }
-
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