[PATCH 3.12 71/83] kvm: commonize allocation of the new memory slots

From: Jiri Slaby
Date: Mon Apr 27 2015 - 17:44:42 EST


From: Paolo Bonzini <pbonzini@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit f2a81036516e2b97c07c49dd6d51d36bfa43593d upstream.

The two kmemdup invocations can be unified. I find that the new
placement of the comment makes it easier to see what happens.

Reviewed-by: Igor Mammedov <imammedo@xxxxxxxxxx>
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
virt/kvm/kvm_main.c | 28 +++++++++++-----------------
1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index feffb3f7c393..cf0c07786204 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -841,11 +841,12 @@ int __kvm_set_memory_region(struct kvm *kvm,
goto out_free;
}

+ slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
+ GFP_KERNEL);
+ if (!slots)
+ goto out_free;
+
if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
- slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
- GFP_KERNEL);
- if (!slots)
- goto out_free;
slot = id_to_memslot(slots, mem->slot);
slot->flags |= KVM_MEMSLOT_INVALID;

@@ -861,6 +862,12 @@ int __kvm_set_memory_region(struct kvm *kvm,
* - kvm_is_visible_gfn (mmu_check_roots)
*/
kvm_arch_flush_shadow_memslot(kvm, slot);
+
+ /*
+ * We can re-use the old_memslots from above, the only difference
+ * from the currently installed memslots is the invalid flag. This
+ * will get overwritten by update_memslots anyway.
+ */
slots = old_memslots;
}

@@ -868,19 +875,6 @@ int __kvm_set_memory_region(struct kvm *kvm,
if (r)
goto out_slots;

- r = -ENOMEM;
- /*
- * We can re-use the old_memslots from above, the only difference
- * from the currently installed memslots is the invalid flag. This
- * will get overwritten by update_memslots anyway.
- */
- if (!slots) {
- slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
- GFP_KERNEL);
- if (!slots)
- goto out_free;
- }
-
/*
* IOMMU mapping: New slots need to be mapped. Old slots need to be
* un-mapped and re-mapped if their base changes. Since base change
--
2.3.5

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