Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

# gpg: Signature made Fri 16 Oct 2015 14:36:50 BST using RSA key ID C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"

* remotes/kevin/tags/for-upstream: (29 commits)
  blkdebug: Don't confuse image as backing file
  qcow2: Remove forward declaration of QCowAIOCB
  qemu-nbd: always compile in --aio=MODE option
  blockdev: always compile in -drive aio= parsing
  raw-posix: warn about BDRV_O_NATIVE_AIO if libaio is unavailable
  block: auto-generated node-names
  util - add automated ID generation utility
  blkverify: Fix BDS leak in .bdrv_open error path
  block: Allow bdrv_unref_child(bs, NULL)
  block: Remove bdrv_swap()
  block: Add and use bdrv_replace_in_backing_chain()
  blockjob: Store device name at job creation
  block: Implement bdrv_append() without bdrv_swap()
  block: Introduce parents list
  block-backend: Add blk_set_bs()
  block/io: Make bdrv_requests_pending() public
  block: Split bdrv_move_feature_fields()
  block: Manage backing file references in bdrv_set_backing_hd()
  block: Convert bs->backing_hd to BdrvChild
  block: Remove bdrv_open_image()
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/util/id.c b/util/id.c
index 09b22fb..bcc64d8 100644
--- a/util/id.c
+++ b/util/id.c
@@ -26,3 +26,40 @@ bool id_wellformed(const char *id)
     }
     return true;
 }
+
+#define ID_SPECIAL_CHAR '#'
+
+static const char *const id_subsys_str[] = {
+    [ID_QDEV]  = "qdev",
+    [ID_BLOCK] = "block",
+};
+
+/*
+ *  Generates an ID of the form PREFIX SUBSYSTEM NUMBER
+ *  where:
+ *
+ *  - PREFIX is the reserved character '#'
+ *  - SUBSYSTEM identifies the subsystem creating the ID
+ *  - NUMBER is a decimal number unique within SUBSYSTEM.
+ *
+ *    Example: "#block146"
+ *
+ * Note that these IDs do not satisfy id_wellformed().
+ *
+ * The caller is responsible for freeing the returned string with g_free()
+ */
+char *id_generate(IdSubSystems id)
+{
+    static uint64_t id_counters[ID_MAX];
+    uint32_t rnd;
+
+    assert(id < ID_MAX);
+    assert(id_subsys_str[id]);
+
+    rnd = g_random_int_range(0, 100);
+
+    return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR,
+                                                        id_subsys_str[id],
+                                                        id_counters[id]++,
+                                                        rnd);
+}