Factor out a new scheduleMdevctlUpdate() function so that we can re-use
it from other places. Now that other events can make it necessary to
re-query mdevctl for mdev updates, this function will be useful for
coalescing multiple updates in quick succession into a single mdevctl
query.

Also rename a couple functions. The names weren't very descriptive of
their behavior. For example, the old scheduleMdevctlHandler() function
didn't actually schedule anything, it just started a thread. So rename
it to free up the 'schedule' name for the above refactored function.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
---
 src/node_device/node_device_udev.c | 37 ++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c
index fce4212728..9ba550dbc1 100644
--- a/src/node_device/node_device_udev.c
+++ b/src/node_device/node_device_udev.c
@@ -2075,7 +2075,7 @@ udevPCITranslateInit(bool privileged G_GNUC_UNUSED)
 
 
 static void
-mdevctlHandlerThread(void *opaque G_GNUC_UNUSED)
+mdevctlUpdateThreadFunc(void *opaque G_GNUC_UNUSED)
 {
     udevEventData *priv = driver->privateData;
     VIR_LOCK_GUARD lock = virLockGuardLock(&priv->mdevctlLock);
@@ -2085,8 +2085,9 @@ mdevctlHandlerThread(void *opaque G_GNUC_UNUSED)
 }
 
 
+
 static void
-scheduleMdevctlHandler(int timer G_GNUC_UNUSED, void *opaque)
+launchMdevctlUpdateThread(int timer G_GNUC_UNUSED, void *opaque)
 {
     udevEventData *priv = opaque;
     virThread thread;
@@ -2096,7 +2097,7 @@ scheduleMdevctlHandler(int timer G_GNUC_UNUSED, void *opaque)
         priv->mdevctlTimeout = -1;
     }
 
-    if (virThreadCreateFull(&thread, false, mdevctlHandlerThread,
+    if (virThreadCreateFull(&thread, false, mdevctlUpdateThreadFunc,
                             "mdevctl-thread", false, NULL) < 0) {
         virReportSystemError(errno, "%s",
                              _("failed to create mdevctl thread"));
@@ -2192,6 +2193,26 @@ mdevctlEnableMonitor(udevEventData *priv)
 }
 
 
+/* Schedules an mdevctl update for 100ms in the future, canceling any existing
+ * timeout that may have been set. In this way, multiple update requests in
+ * quick succession can be collapsed into a single update. if @force is true,
+ * an update thread will be spawned immediately. */
+static void
+scheduleMdevctlUpdate(udevEventData *data,
+                      bool force)
+{
+    if (!force) {
+        if (data->mdevctlTimeout > 0)
+            virEventRemoveTimeout(data->mdevctlTimeout);
+        data->mdevctlTimeout = virEventAddTimeout(100, launchMdevctlUpdateThread,
+                                                  data, NULL);
+        return;
+    }
+
+    launchMdevctlUpdateThread(-1, data);
+}
+
+
 static void
 mdevctlEventHandleCallback(GFileMonitor *monitor G_GNUC_UNUSED,
                            GFile *file,
@@ -2222,15 +2243,7 @@ mdevctlEventHandleCallback(GFileMonitor *monitor G_GNUC_UNUSED,
      * configuration change, try to coalesce these changes by waiting for the
      * CHANGES_DONE_HINT event. As a fallback,  add a timeout to trigger the
      * signal if that event never comes */
-    if (event_type != G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT) {
-        if (priv->mdevctlTimeout > 0)
-            virEventRemoveTimeout(priv->mdevctlTimeout);
-        priv->mdevctlTimeout = virEventAddTimeout(100, scheduleMdevctlHandler,
-                                                  priv, NULL);
-        return;
-    }
-
-    scheduleMdevctlHandler(-1, priv);
+    scheduleMdevctlUpdate(priv, (event_type == G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT));
 }
 
 
-- 
2.41.0

On 7/6/23 9:44 PM, Jonathon Jongsma wrote:
> Factor out a new scheduleMdevctlUpdate() function so that we can re-use
> it from other places. Now that other events can make it necessary to
> re-query mdevctl for mdev updates, this function will be useful for
> coalescing multiple updates in quick succession into a single mdevctl
> query.
> 
> Also rename a couple functions. The names weren't very descriptive of
> their behavior. For example, the old scheduleMdevctlHandler() function
> didn't actually schedule anything, it just started a thread. So rename
> it to free up the 'schedule' name for the above refactored function.
> 
> Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
> ---
>   src/node_device/node_device_udev.c | 37 ++++++++++++++++++++----------
>   1 file changed, 25 insertions(+), 12 deletions(-)
> 
> diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c
> index fce4212728..9ba550dbc1 100644
> --- a/src/node_device/node_device_udev.c
> +++ b/src/node_device/node_device_udev.c
> @@ -2075,7 +2075,7 @@ udevPCITranslateInit(bool privileged G_GNUC_UNUSED)
>   
>   
>   static void
> -mdevctlHandlerThread(void *opaque G_GNUC_UNUSED)
> +mdevctlUpdateThreadFunc(void *opaque G_GNUC_UNUSED)
>   {
>       udevEventData *priv = driver->privateData;
>       VIR_LOCK_GUARD lock = virLockGuardLock(&priv->mdevctlLock);
> @@ -2085,8 +2085,9 @@ mdevctlHandlerThread(void *opaque G_GNUC_UNUSED)
>   }
>   
>   
> +
The above additional line should be removed.

>   static void
> -scheduleMdevctlHandler(int timer G_GNUC_UNUSED, void *opaque)
> +launchMdevctlUpdateThread(int timer G_GNUC_UNUSED, void *opaque)
>   {
>       udevEventData *priv = opaque;
>       virThread thread;
> @@ -2096,7 +2097,7 @@ scheduleMdevctlHandler(int timer G_GNUC_UNUSED, void *opaque)
>           priv->mdevctlTimeout = -1;
>       }
>   
> -    if (virThreadCreateFull(&thread, false, mdevctlHandlerThread,
> +    if (virThreadCreateFull(&thread, false, mdevctlUpdateThreadFunc,
>                               "mdevctl-thread", false, NULL) < 0) {
>           virReportSystemError(errno, "%s",
>                                _("failed to create mdevctl thread"));
> @@ -2192,6 +2193,26 @@ mdevctlEnableMonitor(udevEventData *priv)
>   }
<snip>

Beside the nit above
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>

-- 
Mit freundlichen Grüßen/Kind regards
    Boris Fiuczynski

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