[Xen-devel] [PATCH v7 05/15] libxl: refactor disk addition to take a helper

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Change libxl__device_disk_add to no longer take a xs transaction and
instead pass a helper for the local attach case that's used to get the
free vdev.

Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxx>
---
 tools/libxl/libxl.c          |   80 ++++++++++++++++++++++++++---------------
 tools/libxl/libxl_internal.h |    2 +-
 2 files changed, 52 insertions(+), 30 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 7e6d5c9..10176f0 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1733,15 +1733,23 @@ int libxl__device_from_disk(libxl__gc *gc, uint32_t 
domid,
     return 0;
 }
 
-int libxl__device_disk_add(libxl__gc *gc, uint32_t domid,
-        xs_transaction_t t, libxl_device_disk *disk)
+/* Specific function called directly only by local disk attach,
+ * all other users should instead use the regular
+ * libxl__device_disk_add wrapper
+ */
+static int device_disk_add(libxl__gc *gc, uint32_t domid,
+                           libxl_device_disk *disk,
+                           char *(*fn)(libxl__gc *, const char *,
+                                              xs_transaction_t),
+                           const char *blkdev_start)
 {
     flexarray_t *front;
     flexarray_t *back;
     char *dev;
     libxl__device device;
-    int major, minor, rc;
+    int major, minor, rc, xs_ret;
     libxl_ctx *ctx = gc->owner;
+    xs_transaction_t t = XBT_NULL;
 
     rc = libxl__device_disk_setdefault(gc, disk);
     if (rc) goto out;
@@ -1839,9 +1847,33 @@ int libxl__device_disk_add(libxl__gc *gc, uint32_t domid,
     flexarray_append(front, "device-type");
     flexarray_append(front, disk->is_cdrom ? "cdrom" : "disk");
 
-    libxl__device_generic_add(gc, t, &device,
-                             libxl__xs_kvs_of_flexarray(gc, back, back->count),
-                             libxl__xs_kvs_of_flexarray(gc, front, 
front->count));
+    do {
+        t = xs_transaction_start(ctx->xsh);
+        if (t == XBT_NULL) {
+            LOG(ERROR, "failed to start a xenstore transaction");
+            rc = ERROR_FAIL;
+            goto out_free;
+        }
+        if (fn) {
+            assert(blkdev_start);
+            disk->vdev = fn(gc, blkdev_start, t);
+            if (disk->vdev == NULL) {
+                LOG(ERROR, "libxl__alloc_vdev failed");
+                rc = ERROR_FAIL;
+                goto out_free;
+            }
+        }
+        libxl__device_generic_add(gc, t, &device,
+                        libxl__xs_kvs_of_flexarray(gc, back, back->count),
+                        libxl__xs_kvs_of_flexarray(gc, front, front->count));
+        xs_ret = xs_transaction_end(ctx->xsh, t, 0);
+    } while (xs_ret == 0 && errno == EAGAIN);
+    t = XBT_NULL;
+    if (xs_ret == 0) {
+        LOGE(ERROR, "xenstore transaction failed");
+        rc = ERROR_FAIL;
+        goto out_free;
+    }
 
     rc = 0;
 
@@ -1849,13 +1881,21 @@ out_free:
     flexarray_free(back);
     flexarray_free(front);
 out:
+    if (t != XBT_NULL)
+        xs_transaction_end(ctx->xsh, t, 0);
     return rc;
 }
 
+int libxl__device_disk_add(libxl__gc *gc, uint32_t domid,
+                           libxl_device_disk *disk)
+{
+    return device_disk_add(gc, domid, disk, NULL, NULL);
+}
+
 int libxl_device_disk_add(libxl_ctx *ctx, uint32_t domid, libxl_device_disk 
*disk)
 {
     GC_INIT(ctx);
-    int rc = libxl__device_disk_add(gc, domid, XBT_NULL, disk);
+    int rc = libxl__device_disk_add(gc, domid, disk);
     GC_FREE;
     return rc;
 }
@@ -2113,7 +2153,7 @@ char * libxl__device_disk_local_attach(libxl__gc *gc,
     libxl_ctx *ctx = gc->owner;
     char *dev = NULL, *be_path = NULL;
     char *ret = NULL;
-    int rc, xs_ret;
+    int rc;
     libxl__device device;
     xs_transaction_t t = XBT_NULL;
 
@@ -2159,27 +2199,9 @@ char * libxl__device_disk_local_attach(libxl__gc *gc,
             break;
         case LIBXL_DISK_BACKEND_QDISK:
             if (disk->format != LIBXL_DISK_FORMAT_RAW) {
-                do {
-                    t = xs_transaction_start(ctx->xsh);
-                    if (t == XBT_NULL) {
-                        LOG(ERROR, "failed to start a xenstore transaction");
-                        goto out;
-                    }
-                    disk->vdev = libxl__alloc_vdev(gc, blkdev_start, t);
-                    if (disk->vdev == NULL) {
-                        LOG(ERROR, "libxl__alloc_vdev failed");
-                        goto out;
-                    }
-                    if (libxl__device_disk_add(gc, LIBXL_TOOLSTACK_DOMID,
-                                t, disk)) {
-                        LOG(ERROR, "libxl_device_disk_add failed");
-                        goto out;
-                    }
-                    xs_ret = xs_transaction_end(ctx->xsh, t, 0);
-                } while (xs_ret == 0 && errno == EAGAIN);
-                t = XBT_NULL;
-                if (xs_ret == 0) {
-                    LOGE(ERROR, "xenstore transaction failed");
+                if (device_disk_add(gc, LIBXL_TOOLSTACK_DOMID, disk,
+                                    libxl__alloc_vdev, blkdev_start)) {
+                    LOG(ERROR, "libxl_device_disk_add failed");
                     goto out;
                 }
                 dev = GCSPRINTF("/dev/%s", disk->vdev);
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 7a75809..1befdc5 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1291,7 +1291,7 @@ _hidden int libxl__device_from_disk(libxl__gc *gc, 
uint32_t domid,
                                    libxl_device_disk *disk,
                                    libxl__device *device);
 _hidden int libxl__device_disk_add(libxl__gc *gc, uint32_t domid,
-        xs_transaction_t t, libxl_device_disk *disk);
+                                   libxl_device_disk *disk);
 
 /*
  * Make a disk available in this (the control) domain. Returns path to
-- 
1.7.7.5 (Apple Git-26)


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