[RFC v6 10/24] vfio: Introduce hostwin_from_range helper

[Eric Auger <eric.auger@redhat.com>]

Let's introduce a hostwin_from_range() helper that returns the
hostwin encapsulating an IOVA range or NULL if none is found.

This improves the readibility of callers and removes the usage
of hostwin_found.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 hw/vfio/common.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index ac417b5dbd..f20b37fbee 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -499,6 +499,19 @@ out:
     rcu_read_unlock();
 }
 
+static VFIOHostDMAWindow *
+hostwin_from_range(VFIOContainer *container, hwaddr iova, hwaddr end)
+{
+    VFIOHostDMAWindow *hostwin;
+
+    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
+        if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
+            return hostwin;
+        }
+    }
+    return NULL;
+}
+
 static void vfio_listener_region_add(MemoryListener *listener,
                                      MemoryRegionSection *section)
 {
@@ -508,7 +521,6 @@ static void vfio_listener_region_add(MemoryListener *listener,
     void *vaddr;
     int ret;
     VFIOHostDMAWindow *hostwin;
-    bool hostwin_found;
     Error *err = NULL;
 
     if (vfio_listener_skipped_section(section)) {
@@ -593,15 +605,8 @@ static void vfio_listener_region_add(MemoryListener *listener,
 #endif
     }
 
-    hostwin_found = false;
-    QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
-        if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
-            hostwin_found = true;
-            break;
-        }
-    }
-
-    if (!hostwin_found) {
+    hostwin = hostwin_from_range(container, iova, end);
+    if (!hostwin) {
         error_setg(&err, "Container %p can't map guest IOVA region"
                    " 0x%"HWADDR_PRIx"..0x%"HWADDR_PRIx, container, iova, end);
         goto fail;
@@ -774,16 +779,9 @@ static void vfio_listener_region_del(MemoryListener *listener,
 
     if (memory_region_is_ram_device(section->mr)) {
         hwaddr pgmask;
-        VFIOHostDMAWindow *hostwin;
-        bool hostwin_found = false;
+        VFIOHostDMAWindow *hostwin = hostwin_from_range(container, iova, end);
 
-        QLIST_FOREACH(hostwin, &container->hostwin_list, hostwin_next) {
-            if (hostwin->min_iova <= iova && end <= hostwin->max_iova) {
-                hostwin_found = true;
-                break;
-            }
-        }
-        assert(hostwin_found); /* or region_add() would have failed */
+        assert(hostwin); /* or region_add() would have failed */
 
         pgmask = (1ULL << ctz64(hostwin->iova_pgsizes)) - 1;
         try_unmap = !((iova & pgmask) || (int128_get64(llsize) & pgmask));
-- 
2.20.1