[PULL 4/6] xen: when removing a backend don't remove many of them

[PULL 4/6] xen: when removing a backend don't remove many of them

[Gerd Hoffmann]

From: Juergen Gross <jgross@suse.com>

When a Xenstore watch fires indicating a backend has to be removed
don't remove all backends for that domain with the specified device
index, but just the one which has the correct type.

The easiest way to achieve this is to use the already determined
xendev as parameter for xen_be_del_xendev() instead of only the domid
and device index.

This at once removes the open coded QTAILQ_FOREACH_SAVE() in
xen_be_del_xendev() as there is no need to search for the correct
xendev any longer.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Message-id: 1470140044-16492-2-git-send-email-jgross@suse.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/xen/xen_backend.c | 58 +++++++++++++++++-----------------------------------
 1 file changed, 19 insertions(+), 39 deletions(-)

diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index bab79b1..3ceb778 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -321,48 +321,28 @@ static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
 /*
  * release xen backend device.
  */
-static struct XenDevice *xen_be_del_xendev(int dom, int dev)
+static void xen_be_del_xendev(struct XenDevice *xendev)
 {
-    struct XenDevice *xendev, *xnext;
-
-    /*
-     * This is pretty much like QTAILQ_FOREACH(xendev, &xendevs, next) but
-     * we save the next pointer in xnext because we might free xendev.
-     */
-    xnext = xendevs.tqh_first;
-    while (xnext) {
-        xendev = xnext;
-        xnext = xendev->next.tqe_next;
-
-        if (xendev->dom != dom) {
-            continue;
-        }
-        if (xendev->dev != dev && dev != -1) {
-            continue;
-        }
-
-        if (xendev->ops->free) {
-            xendev->ops->free(xendev);
-        }
-
-        if (xendev->fe) {
-            char token[XEN_BUFSIZE];
-            snprintf(token, sizeof(token), "fe:%p", xendev);
-            xs_unwatch(xenstore, xendev->fe, token);
-            g_free(xendev->fe);
-        }
+    if (xendev->ops->free) {
+        xendev->ops->free(xendev);
+    }
 
-        if (xendev->evtchndev != NULL) {
-            xenevtchn_close(xendev->evtchndev);
-        }
-        if (xendev->gnttabdev != NULL) {
-            xengnttab_close(xendev->gnttabdev);
-        }
+    if (xendev->fe) {
+        char token[XEN_BUFSIZE];
+        snprintf(token, sizeof(token), "fe:%p", xendev);
+        xs_unwatch(xenstore, xendev->fe, token);
+        g_free(xendev->fe);
+    }
 
-        QTAILQ_REMOVE(&xendevs, xendev, next);
-        g_free(xendev);
+    if (xendev->evtchndev != NULL) {
+        xenevtchn_close(xendev->evtchndev);
     }
-    return NULL;
+    if (xendev->gnttabdev != NULL) {
+        xengnttab_close(xendev->gnttabdev);
+    }
+
+    QTAILQ_REMOVE(&xendevs, xendev, next);
+    g_free(xendev);
 }
 
 /*
@@ -682,7 +662,7 @@ static void xenstore_update_be(char *watch, char *type, int dom,
     if (xendev != NULL) {
         bepath = xs_read(xenstore, 0, xendev->be, &len);
         if (bepath == NULL) {
-            xen_be_del_xendev(dom, dev);
+            xen_be_del_xendev(xendev);
         } else {
             free(bepath);
             xen_be_backend_changed(xendev, path);
-- 
1.8.3.1


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[PULL 6/6] xen: use a common function for pv and hvm guest backend register calls

[Gerd Hoffmann]

From: Juergen Gross <jgross@suse.com>

Instead of calling xen_be_register() for each supported backend type
for hvm and pv guests in their machine init functions use a common
function in order not to have to add new backends twice.

This at once fixes the error that hvm domains couldn't use the qusb
backend.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Message-id: 1470119552-16170-1-git-send-email-jgross@suse.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/xen/xen_backend.c         | 10 ++++++++++
 hw/xenpv/xen_machine_pv.c    |  7 +------
 include/hw/xen/xen_backend.h |  1 +
 xen-hvm.c                    |  4 +---
 4 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index 3ceb778..69a2388 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -780,6 +780,16 @@ int xen_be_register(const char *type, struct XenDevOps *ops)
     return xenstore_scan(type, xen_domid, ops);
 }
 
+void xen_be_register_common(void)
+{
+    xen_be_register("console", &xen_console_ops);
+    xen_be_register("vkbd", &xen_kbdmouse_ops);
+    xen_be_register("qdisk", &xen_blkdev_ops);
+#ifdef CONFIG_USB_LIBUSB
+    xen_be_register("qusb", &xen_usb_ops);
+#endif
+}
+
 int xen_be_bind_evtchn(struct XenDevice *xendev)
 {
     if (xendev->local_port != -1) {
diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
index 48f725c..79aef4e 100644
--- a/hw/xenpv/xen_machine_pv.c
+++ b/hw/xenpv/xen_machine_pv.c
@@ -67,14 +67,9 @@ static void xen_init_pv(MachineState *machine)
         break;
     }
 
-    xen_be_register("console", &xen_console_ops);
-    xen_be_register("vkbd", &xen_kbdmouse_ops);
+    xen_be_register_common();
     xen_be_register("vfb", &xen_framebuffer_ops);
-    xen_be_register("qdisk", &xen_blkdev_ops);
     xen_be_register("qnic", &xen_netdev_ops);
-#ifdef CONFIG_USB_LIBUSB
-    xen_be_register("qusb", &xen_usb_ops);
-#endif
 
     /* configure framebuffer */
     if (xenfb_enabled) {
diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
index 754c0a4..0df282a 100644
--- a/include/hw/xen/xen_backend.h
+++ b/include/hw/xen/xen_backend.h
@@ -87,6 +87,7 @@ void xen_be_check_state(struct XenDevice *xendev);
 
 /* xen backend driver bits */
 int xen_be_init(void);
+void xen_be_register_common(void);
 int xen_be_register(const char *type, struct XenDevOps *ops);
 int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state);
 int xen_be_bind_evtchn(struct XenDevice *xendev);
diff --git a/xen-hvm.c b/xen-hvm.c
index eb57792..3b0343a 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -1318,9 +1318,7 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
         error_report("xen backend core setup failed");
         goto err;
     }
-    xen_be_register("console", &xen_console_ops);
-    xen_be_register("vkbd", &xen_kbdmouse_ops);
-    xen_be_register("qdisk", &xen_blkdev_ops);
+    xen_be_register_common();
     xen_read_physmap(state);
     return;
 
-- 
1.8.3.1


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