[Xen-changelog] [xen-unstable] cpupool: Fix __cpupool_find_by_id(), clean up accessor functions.

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxx>
# Date 1297241623 0
# Node ID 8ef21ac0b464f244f7d72f768436a1137ddb8aeb
# Parent  fc986c1314bc8d061aa9f0bebc0eb40624089d4b
cpupool: Fix __cpupool_find_by_id(), clean up accessor functions.

Firstly, __cpupool_find_by_id() would dereference NULL, at the end of
an exact search if the search loop exited with *q==NULL. Fix this.

Secondly, provide suitable accessor functions so that no caller needs
to use the __-prefixed versions which take a boolean flag.

Signed-off-by: Keir Fraser <keir@xxxxxxx>
---
 xen/common/cpupool.c |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff -r fc986c1314bc -r 8ef21ac0b464 xen/common/cpupool.c
--- a/xen/common/cpupool.c      Wed Feb 09 08:44:38 2011 +0000
+++ b/xen/common/cpupool.c      Wed Feb 09 08:53:43 2011 +0000
@@ -53,7 +53,7 @@ static void free_cpupool_struct(struct c
  * the searched id is returned
  * returns NULL if not found.
  */
-static struct cpupool *cpupool_find_by_id(int id, int exact)
+static struct cpupool *__cpupool_find_by_id(int id, int exact)
 {
     struct cpupool **q;
 
@@ -63,14 +63,19 @@ static struct cpupool *cpupool_find_by_i
         if ( (*q)->cpupool_id >= id )
             break;
 
-    return (!exact || ((*q)->cpupool_id == id)) ? *q : NULL;
+    return (!exact || (*q == NULL) || ((*q)->cpupool_id == id)) ? *q : NULL;
+}
+
+static struct cpupool *cpupool_find_by_id(int poolid)
+{
+    return __cpupool_find_by_id(poolid, 1);
 }
 
 static struct cpupool *__cpupool_get_by_id(int poolid, int exact)
 {
     struct cpupool *c;
     spin_lock(&cpupool_lock);
-    c = cpupool_find_by_id(poolid, exact);
+    c = __cpupool_find_by_id(poolid, exact);
     if ( c != NULL )
         atomic_inc(&c->refcnt);
     spin_unlock(&cpupool_lock);
@@ -80,6 +85,11 @@ struct cpupool *cpupool_get_by_id(int po
 struct cpupool *cpupool_get_by_id(int poolid)
 {
     return __cpupool_get_by_id(poolid, 1);
+}
+
+static struct cpupool *cpupool_get_next_by_id(int poolid)
+{
+    return __cpupool_get_by_id(poolid, 0);
 }
 
 void cpupool_put(struct cpupool *pool)
@@ -351,7 +361,7 @@ int cpupool_add_domain(struct domain *d,
     if ( poolid == CPUPOOLID_NONE )
         return 0;
     spin_lock(&cpupool_lock);
-    c = cpupool_find_by_id(poolid, 1);
+    c = cpupool_find_by_id(poolid);
     if ( (c != NULL) && cpus_weight(c->cpu_valid) )
     {
         c->n_dom++;
@@ -457,7 +467,7 @@ int cpupool_do_sysctl(struct xen_sysctl_
 
     case XEN_SYSCTL_CPUPOOL_OP_INFO:
     {
-        c = __cpupool_get_by_id(op->cpupool_id, 0);
+        c = cpupool_get_next_by_id(op->cpupool_id);
         ret = -ENOENT;
         if ( c == NULL )
             break;
@@ -485,7 +495,7 @@ int cpupool_do_sysctl(struct xen_sysctl_
         ret = -EBUSY;
         if ( !cpu_isset(cpu, cpupool_free_cpus) )
             goto addcpu_out;
-        c = cpupool_find_by_id(op->cpupool_id, 1);
+        c = cpupool_find_by_id(op->cpupool_id);
         ret = -ENOENT;
         if ( c == NULL )
             goto addcpu_out;
@@ -501,7 +511,7 @@ int cpupool_do_sysctl(struct xen_sysctl_
     {
         unsigned cpu;
 
-        c = __cpupool_get_by_id(op->cpupool_id, 1);
+        c = cpupool_get_by_id(op->cpupool_id);
         ret = -ENOENT;
         if ( c == NULL )
             break;
@@ -540,7 +550,7 @@ int cpupool_do_sysctl(struct xen_sysctl_
                         d->domain_id, op->cpupool_id);
         ret = -ENOENT;
         spin_lock(&cpupool_lock);
-        c = cpupool_find_by_id(op->cpupool_id, 1);
+        c = cpupool_find_by_id(op->cpupool_id);
         if ( (c != NULL) && cpus_weight(c->cpu_valid) )
         {
             d->cpupool->n_dom--;

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