[PATCH v3 06/17] tools/xenstore: move changed domain handling

[Juergen Gross <jgross@xxxxxxxx>]

Move all code related to struct changed_domain from
xenstored_transaction.c to xenstored_domain.c.

This will be needed later in order to simplify the accounting data
updates in cases of errors during a request.

Split the code to have a more generic base framework.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V2:
- remove unrelated change (Julien Grall)
V3:
- modify acc_add_dom_nbentry() interface (Julien Grall)
---
 tools/xenstore/xenstored_domain.c      | 78 ++++++++++++++++++++++++++
 tools/xenstore/xenstored_domain.h      |  3 +
 tools/xenstore/xenstored_transaction.c | 64 ++-------------------
 3 files changed, 85 insertions(+), 60 deletions(-)

diff --git a/tools/xenstore/xenstored_domain.c 
b/tools/xenstore/xenstored_domain.c
index 99f0afcb1f..3a2ab5d87e 100644
--- a/tools/xenstore/xenstored_domain.c
+++ b/tools/xenstore/xenstored_domain.c
@@ -91,6 +91,18 @@ struct domain
        bool wrl_delay_logged;
 };
 
+struct changed_domain
+{
+       /* List of all changed domains. */
+       struct list_head list;
+
+       /* Identifier of the changed domain. */
+       unsigned int domid;
+
+       /* Amount by which this domain's nbentry field has changed. */
+       int nbentry;
+};
+
 static struct hashtable *domhash;
 
 static bool check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod)
@@ -543,6 +555,72 @@ static struct domain *find_domain_by_domid(unsigned int 
domid)
        return (d && d->introduced) ? d : NULL;
 }
 
+int acc_fix_domains(struct list_head *head, bool update)
+{
+       struct changed_domain *cd;
+       int cnt;
+
+       list_for_each_entry(cd, head, list) {
+               cnt = domain_entry_fix(cd->domid, cd->nbentry, update);
+               if (!update) {
+                       if (cnt >= quota_nb_entry_per_domain)
+                               return ENOSPC;
+                       if (cnt < 0)
+                               return ENOMEM;
+               }
+       }
+
+       return 0;
+}
+
+static struct changed_domain *acc_find_changed_domain(struct list_head *head,
+                                                     unsigned int domid)
+{
+       struct changed_domain *cd;
+
+       list_for_each_entry(cd, head, list) {
+               if (cd->domid == domid)
+                       return cd;
+       }
+
+       return NULL;
+}
+
+static struct changed_domain *acc_get_changed_domain(const void *ctx,
+                                                    struct list_head *head,
+                                                    unsigned int domid)
+{
+       struct changed_domain *cd;
+
+       cd = acc_find_changed_domain(head, domid);
+       if (cd)
+               return cd;
+
+       cd = talloc_zero(ctx, struct changed_domain);
+       if (!cd)
+               return NULL;
+
+       cd->domid = domid;
+       list_add_tail(&cd->list, head);
+
+       return cd;
+}
+
+int acc_add_dom_nbentry(const void *ctx, struct list_head *head, int val,
+                       unsigned int domid)
+{
+       struct changed_domain *cd;
+
+       cd = acc_get_changed_domain(ctx, head, domid);
+       if (!cd)
+               return 0;
+
+       errno = 0;
+       cd->nbentry += val;
+
+       return cd->nbentry;
+}
+
 static void domain_conn_reset(struct domain *domain)
 {
        struct connection *conn = domain->conn;
diff --git a/tools/xenstore/xenstored_domain.h 
b/tools/xenstore/xenstored_domain.h
index 630641d620..9e20d2b17d 100644
--- a/tools/xenstore/xenstored_domain.h
+++ b/tools/xenstore/xenstored_domain.h
@@ -98,6 +98,9 @@ void domain_outstanding_dec(struct connection *conn);
 void domain_outstanding_domid_dec(unsigned int domid);
 int domain_get_quota(const void *ctx, struct connection *conn,
                     unsigned int domid);
+int acc_fix_domains(struct list_head *head, bool update);
+int acc_add_dom_nbentry(const void *ctx, struct list_head *head, int val,
+                       unsigned int domid);
 
 /* Write rate limiting */
 
diff --git a/tools/xenstore/xenstored_transaction.c 
b/tools/xenstore/xenstored_transaction.c
index ac854197ca..c009c67989 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -137,18 +137,6 @@ struct accessed_node
        bool watch_exact;
 };
 
-struct changed_domain
-{
-       /* List of all changed domains in the context of this transaction. */
-       struct list_head list;
-
-       /* Identifier of the changed domain. */
-       unsigned int domid;
-
-       /* Amount by which this domain's nbentry field has changed. */
-       int nbentry;
-};
-
 struct transaction
 {
        /* List of all transactions active on this connection. */
@@ -514,24 +502,6 @@ int do_transaction_start(const void *ctx, struct 
connection *conn,
        return 0;
 }
 
-static int transaction_fix_domains(struct transaction *trans, bool update)
-{
-       struct changed_domain *d;
-       int cnt;
-
-       list_for_each_entry(d, &trans->changed_domains, list) {
-               cnt = domain_entry_fix(d->domid, d->nbentry, update);
-               if (!update) {
-                       if (cnt >= quota_nb_entry_per_domain)
-                               return ENOSPC;
-                       if (cnt < 0)
-                               return ENOMEM;
-               }
-       }
-
-       return 0;
-}
-
 int do_transaction_end(const void *ctx, struct connection *conn,
                       struct buffered_data *in)
 {
@@ -558,7 +528,7 @@ int do_transaction_end(const void *ctx, struct connection 
*conn,
        if (streq(arg, "T")) {
                if (trans->fail)
                        return ENOMEM;
-               ret = transaction_fix_domains(trans, false);
+               ret = acc_fix_domains(&trans->changed_domains, false);
                if (ret)
                        return ret;
                ret = finalize_transaction(conn, trans, &is_corrupt);
@@ -568,7 +538,7 @@ int do_transaction_end(const void *ctx, struct connection 
*conn,
                wrl_apply_debit_trans_commit(conn);
 
                /* fix domain entry for each changed domain */
-               transaction_fix_domains(trans, true);
+               acc_fix_domains(&trans->changed_domains, true);
 
                if (is_corrupt)
                        corrupt(conn, "transaction inconsistency");
@@ -580,44 +550,18 @@ int do_transaction_end(const void *ctx, struct connection 
*conn,
 
 void transaction_entry_inc(struct transaction *trans, unsigned int domid)
 {
-       struct changed_domain *d;
-
-       list_for_each_entry(d, &trans->changed_domains, list)
-               if (d->domid == domid) {
-                       d->nbentry++;
-                       return;
-               }
-
-       d = talloc(trans, struct changed_domain);
-       if (!d) {
+       if (!acc_add_dom_nbentry(trans, &trans->changed_domains, 1, domid)) {
                /* Let the transaction fail. */
                trans->fail = true;
-               return;
        }
-       d->domid = domid;
-       d->nbentry = 1;
-       list_add_tail(&d->list, &trans->changed_domains);
 }
 
 void transaction_entry_dec(struct transaction *trans, unsigned int domid)
 {
-       struct changed_domain *d;
-
-       list_for_each_entry(d, &trans->changed_domains, list)
-               if (d->domid == domid) {
-                       d->nbentry--;
-                       return;
-               }
-
-       d = talloc(trans, struct changed_domain);
-       if (!d) {
+       if (!acc_add_dom_nbentry(trans, &trans->changed_domains, -1, domid)) {
                /* Let the transaction fail. */
                trans->fail = true;
-               return;
        }
-       d->domid = domid;
-       d->nbentry = -1;
-       list_add_tail(&d->list, &trans->changed_domains);
 }
 
 void fail_transaction(struct transaction *trans)
-- 
2.35.3