[Xen-changelog] [xen master] xen/domain: Break _domain_destroy() out of domain_create() and complete_domain_destroy()

[patchbot@xxxxxxx]

commit 9247403d271bcb0071e87fd1fd6aee662aacfdde
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Mon Sep 3 11:52:17 2018 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Sep 4 13:25:44 2018 +0100

    xen/domain: Break _domain_destroy() out of domain_create() and 
complete_domain_destroy()
    
    This is the first step in making the destroy path idempotent, and using it 
in
    place of the ad-hoc cleanup paths in the create path.
    
    To begin with, the trivial free operations are broken out.  The rest of the
    cleanup code will be moved as it is demonstrated (or made) to be idempotent.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/common/domain.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 43ab926a1c..b0988763a3 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -260,6 +260,23 @@ static int __init parse_extra_guest_irqs(const char *s)
 }
 custom_param("extra_guest_irqs", parse_extra_guest_irqs);
 
+/*
+ * Destroy a domain once all references to it have been dropped.  Used either
+ * from the RCU path, or from the domain_create() error path before the domain
+ * is inserted into the domlist.
+ */
+static void _domain_destroy(struct domain *d)
+{
+    BUG_ON(!d->is_dying);
+    BUG_ON(atomic_read(&d->refcnt) != DOMAIN_DESTROYED);
+
+    xfree(d->pbuf);
+
+    free_cpumask_var(d->dirty_cpumask);
+
+    free_domain_struct(d);
+}
+
 struct domain *domain_create(domid_t domid,
                              struct xen_domctl_createdomain *config,
                              bool is_priv)
@@ -437,7 +454,6 @@ struct domain *domain_create(domid_t domid,
     if ( hardware_domain == d )
         hardware_domain = old_hwdom;
     atomic_set(&d->refcnt, DOMAIN_DESTROYED);
-    xfree(d->pbuf);
 
     sched_destroy_domain(d);
 
@@ -462,8 +478,9 @@ struct domain *domain_create(domid_t domid,
         watchdog_domain_destroy(d);
     if ( init_status & INIT_xsm )
         xsm_free_security_domain(d);
-    free_cpumask_var(d->dirty_cpumask);
-    free_domain_struct(d);
+
+    _domain_destroy(d);
+
     return ERR_PTR(err);
 }
 
@@ -881,8 +898,6 @@ static void complete_domain_destroy(struct rcu_head *head)
     xfree(d->vm_event_share);
 #endif
 
-    xfree(d->pbuf);
-
     for ( i = d->max_vcpus - 1; i >= 0; i-- )
         if ( (v = d->vcpu[i]) != NULL )
         {
@@ -901,9 +916,9 @@ static void complete_domain_destroy(struct rcu_head *head)
     radix_tree_destroy(&d->pirq_tree, free_pirq_struct);
 
     xsm_free_security_domain(d);
-    free_cpumask_var(d->dirty_cpumask);
     xfree(d->vcpu);
-    free_domain_struct(d);
+
+    _domain_destroy(d);
 
     send_global_virq(VIRQ_DOM_EXC);
 }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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