qemu: Refactor qemuCheckSharedDisk to create qemuCheckUnprivSGIO

Split out the current function in order to share the code with hostdev
in a future patch. Failure to match the expected sgio value against what
is stored will cause an error which the caller would need to handle since
only the caller has the disk (or eventually hostdev) specific data in
order to uniquely identify the disk in an error message.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

src/qemu/qemu_conf.c

@@ -1018,26 +1018,28 @@ qemuGetSharedDeviceKey(const char *device_path)
     return key;
 }
 
-/* Check if a shared device's setting conflicts with the conf
- * used by other domain(s). Currently only checks the sgio
- * setting. Note that this should only be called for disk with
- * block source if the device type is disk.
+/*
+ * Make necessary checks for the need to check and for the current setting
+ * of the 'unpriv_sgio' value for the device_path passed.
  *
- * Returns 0 if no conflicts, otherwise returns -1.
+ * Returns:
+ *  0 - Success
+ * -1 - Some failure which would already have been messaged
+ * -2 - Mismatch with the "shared" sgio setting - needs to be messaged
+ *      by caller since it has context of which type of disk resource is
+ *      being used and in the future the hostdev information.
  */
 static int
-qemuCheckSharedDisk(virHashTablePtr sharedDevices,
-                    virDomainDiskDefPtr disk)
+qemuCheckUnprivSGIO(virHashTablePtr sharedDevices,
+                    const char *device_path,
+                    int sgio)
 {
     char *sysfs_path = NULL;
     char *key = NULL;
     int val;
     int ret = -1;
 
-    if (disk->device != VIR_DOMAIN_DISK_DEVICE_LUN)
-        return 0;
-
-    if (!(sysfs_path = virGetUnprivSGIOSysfsPath(disk->src->path, NULL)))
+    if (!(sysfs_path = virGetUnprivSGIOSysfsPath(device_path, NULL)))
         goto cleanup;
 
     /* It can't be conflict if unpriv_sgio is not supported by kernel. */
@@ -1046,7 +1048,7 @@ qemuCheckSharedDisk(virHashTablePtr sharedDevices,
         goto cleanup;
     }
 
-    if (!(key = qemuGetSharedDeviceKey(disk->src->path)))
+    if (!(key = qemuGetSharedDeviceKey(device_path)))
         goto cleanup;
 
     /* It can't be conflict if no other domain is sharing it. */
@@ -1055,27 +1057,18 @@ qemuCheckSharedDisk(virHashTablePtr sharedDevices,
         goto cleanup;
     }
 
-    if (virGetDeviceUnprivSGIO(disk->src->path, NULL, &val) < 0)
+    if (virGetDeviceUnprivSGIO(device_path, NULL, &val) < 0)
         goto cleanup;
 
+    /* Error message on failure needs to be handled in caller
+     * since there is more specific knowledge of device
+     */
     if (!((val == 0 &&
-           (disk->sgio == VIR_DOMAIN_DEVICE_SGIO_FILTERED ||
-            disk->sgio == VIR_DOMAIN_DEVICE_SGIO_DEFAULT)) ||
+           (sgio == VIR_DOMAIN_DEVICE_SGIO_FILTERED ||
+            sgio == VIR_DOMAIN_DEVICE_SGIO_DEFAULT)) ||
           (val == 1 &&
-           disk->sgio == VIR_DOMAIN_DEVICE_SGIO_UNFILTERED))) {
-
-        if (virDomainDiskGetType(disk) == VIR_STORAGE_TYPE_VOLUME) {
-            virReportError(VIR_ERR_OPERATION_INVALID,
-                           _("sgio of shared disk 'pool=%s' 'volume=%s' conflicts "
-                             "with other active domains"),
-                           disk->src->srcpool->pool,
-                           disk->src->srcpool->volume);
-        } else {
-            virReportError(VIR_ERR_OPERATION_INVALID,
-                           _("sgio of shared disk '%s' conflicts with other "
-                             "active domains"), disk->src->path);
-        }
-
+           sgio == VIR_DOMAIN_DEVICE_SGIO_UNFILTERED))) {
+        ret = -2;
         goto cleanup;
     }
 
@@ -1088,6 +1081,45 @@ qemuCheckSharedDisk(virHashTablePtr sharedDevices,
 }
 
 
+/* Check if a shared device's setting conflicts with the conf
+ * used by other domain(s). Currently only checks the sgio
+ * setting. Note that this should only be called for disk with
+ * block source if the device type is disk.
+ *
+ * Returns 0 if no conflicts, otherwise returns -1.
+ */
+static int
+qemuCheckSharedDisk(virHashTablePtr sharedDevices,
+                    virDomainDiskDefPtr disk)
+{
+    int ret;
+
+    if (disk->device != VIR_DOMAIN_DISK_DEVICE_LUN)
+        return 0;
+
+    if ((ret = qemuCheckUnprivSGIO(sharedDevices, disk->src->path,
+                                   disk->sgio)) < 0) {
+        if (ret == -2) {
+            if (virDomainDiskGetType(disk) == VIR_STORAGE_TYPE_VOLUME) {
+                virReportError(VIR_ERR_OPERATION_INVALID,
+                               _("sgio of shared disk 'pool=%s' 'volume=%s' "
+                                 "conflicts with other active domains"),
+                               disk->src->srcpool->pool,
+                               disk->src->srcpool->volume);
+            } else {
+                virReportError(VIR_ERR_OPERATION_INVALID,
+                               _("sgio of shared disk '%s' conflicts with "
+                                 "other active domains"),
+                               disk->src->path);
+            }
+        }
+        return -1;
+    }
+
+    return 0;
+}
+
+
 bool
 qemuSharedDeviceEntryDomainExists(qemuSharedDeviceEntryPtr entry,
                                   const char *name,