From 8c6b6684a8e4d9e6e270b533b58453c1b4ce5281 Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Mon, 16 Oct 2017 13:23:51 +0200
Subject: [PATCH] storage: Extract common code to retrieve driver backend for
 support check

The 'file access' module of the storage driver has few feature checks to
determine whether libvirt supports given storage driver method. The code
to retrieve the driver struct needed for the check is the same so it can
be extracted.
---
 src/storage/storage_source.c | 43 ++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 24 deletions(-)

diff --git a/src/storage/storage_source.c b/src/storage/storage_source.c
index 419fa3d43f..e3c5c3285a 100644
--- a/src/storage/storage_source.c
+++ b/src/storage/storage_source.c
@@ -44,24 +44,30 @@ virStorageFileIsInitialized(const virStorageSource *src)
 }
 
 
-static bool
-virStorageFileSupportsBackingChainTraversal(virStorageSourcePtr src)
+static virStorageFileBackendPtr
+virStorageFileGetBackendForSupportCheck(const virStorageSource *src)
 {
     int actualType;
-    virStorageFileBackendPtr backend;
 
     if (!src)
-        return false;
+        return NULL;
+
+    if (src->drv)
+        return src->drv->backend;
+
     actualType = virStorageSourceGetActualType(src);
 
-    if (src->drv) {
-        backend = src->drv->backend;
-    } else {
-        if (!(backend = virStorageFileBackendForTypeInternal(actualType,
-                                                             src->protocol,
-                                                             false)))
-            return false;
-    }
+    return virStorageFileBackendForTypeInternal(actualType, src->protocol, false);
+}
+
+
+static bool
+virStorageFileSupportsBackingChainTraversal(virStorageSourcePtr src)
+{
+    virStorageFileBackendPtr backend;
+
+    if (!(backend = virStorageFileGetBackendForSupportCheck(src)))
+        return false;
 
     return backend->storageFileGetUniqueIdentifier &&
            backend->storageFileRead &&
@@ -80,21 +86,10 @@ virStorageFileSupportsBackingChainTraversal(virStorageSourcePtr src)
 bool
 virStorageFileSupportsSecurityDriver(const virStorageSource *src)
 {
-    int actualType;
     virStorageFileBackendPtr backend;
 
-    if (!src)
+    if (!(backend = virStorageFileGetBackendForSupportCheck(src)))
         return false;
-    actualType = virStorageSourceGetActualType(src);
-
-    if (src->drv) {
-        backend = src->drv->backend;
-    } else {
-        if (!(backend = virStorageFileBackendForTypeInternal(actualType,
-                                                             src->protocol,
-                                                             false)))
-            return false;
-    }
 
     return !!backend->storageFileChown;
 }
-- 
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