Patchwork [25/40] memory: add ref/unref

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Submitter Paolo Bonzini
Date May 7, 2013, 2:17 p.m.
Message ID <1367936238-12196-26-git-send-email-pbonzini@redhat.com>
Download mbox | patch
Permalink /patch/242371/
State New
Headers show

Comments

Paolo Bonzini - May 7, 2013, 2:17 p.m.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/exec/memory.h |   34 ++++++++++++++++++++++++++++++++++
 memory.c              |   14 ++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)
Stefan Hajnoczi - May 8, 2013, 9:05 a.m.
On Tue, May 07, 2013 at 04:17:03PM +0200, Paolo Bonzini wrote:
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  include/exec/memory.h |   34 ++++++++++++++++++++++++++++++++++
>  memory.c              |   14 ++++++++++++++
>  2 files changed, 48 insertions(+), 0 deletions(-)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 5c20bac..ebac085 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -253,6 +253,40 @@ struct MemoryListener {
>  void memory_region_init(MemoryRegion *mr,
>                          const char *name,
>                          uint64_t size);
> +
> +/**
> + * memory_region_ref: Add 1 to a memory region's reference count
> + *
> + * Whenever memory regions are accessed outside the BQL, they need to be
> + * preserved against hot-unplug.  MemoryRegions actually do not have their
> + * own reference count; they piggyback on a QOM object, their "owner".
> + * This function adds a reference to the owner.
> + *
> + * All MemoryRegions must have an owner if they can disappear, even if the
> + * device they belong to operates exclusively under the BQL.  This is because
> + * the region could be returned at any time by memory_region_find, and this
> + * is usually under guest control.
> + *
> + * @mr: the #MemoryRegion to be initialized

s/to be initialized//

> + * @name: used for debugging; not visible to the user or ABI
> + * @size: size of the region; any subregions beyond this size will be clipped

Copy-pasted.  These can be deleted.

> + */
> +void memory_region_ref(MemoryRegion *mr);
> +
> +/**
> + * memory_region_ref: Remove 1 to a memory region's reference count

s/memory_region_ref/memory_region_unref/

> + *
> + * Whenever memory regions are accessed outside the BQL, they need to be
> + * preserved against hot-unplug.  MemoryRegions actually do not have their
> + * own reference count; they piggyback on a QOM object, their "owner".
> + * This function removes a reference to the owner and possibly destroys it.
> + *
> + * @mr: the #MemoryRegion to be initialized
> + * @name: used for debugging; not visible to the user or ABI
> + * @size: size of the region; any subregions beyond this size will be clipped

Same here.

Patch

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5c20bac..ebac085 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -253,6 +253,40 @@  struct MemoryListener {
 void memory_region_init(MemoryRegion *mr,
                         const char *name,
                         uint64_t size);
+
+/**
+ * memory_region_ref: Add 1 to a memory region's reference count
+ *
+ * Whenever memory regions are accessed outside the BQL, they need to be
+ * preserved against hot-unplug.  MemoryRegions actually do not have their
+ * own reference count; they piggyback on a QOM object, their "owner".
+ * This function adds a reference to the owner.
+ *
+ * All MemoryRegions must have an owner if they can disappear, even if the
+ * device they belong to operates exclusively under the BQL.  This is because
+ * the region could be returned at any time by memory_region_find, and this
+ * is usually under guest control.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region; any subregions beyond this size will be clipped
+ */
+void memory_region_ref(MemoryRegion *mr);
+
+/**
+ * memory_region_ref: Remove 1 to a memory region's reference count
+ *
+ * Whenever memory regions are accessed outside the BQL, they need to be
+ * preserved against hot-unplug.  MemoryRegions actually do not have their
+ * own reference count; they piggyback on a QOM object, their "owner".
+ * This function removes a reference to the owner and possibly destroys it.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region; any subregions beyond this size will be clipped
+ */
+void memory_region_unref(MemoryRegion *mr);
+
 /**
  * memory_region_init_io: Initialize an I/O memory region.
  *
diff --git a/memory.c b/memory.c
index f7fddb1..c7ab19c 100644
--- a/memory.c
+++ b/memory.c
@@ -1061,6 +1061,20 @@  void memory_region_set_owner(MemoryRegion *mr,
     }
 }
 
+void memory_region_ref(MemoryRegion *mr)
+{
+    if (mr && mr->owner) {
+        object_ref(mr->owner);
+    }
+}
+
+void memory_region_unref(MemoryRegion *mr)
+{
+    if (mr && mr->owner) {
+        object_unref(mr->owner);
+    }
+}
+
 uint64_t memory_region_size(MemoryRegion *mr)
 {
     if (int128_eq(mr->size, int128_2_64())) {