tile: various minor cleanups to hardwall subsystem

First, clean up active hardwalls in exit_thread().  This is a better
place than in arch_release_thread_info().

Second, mask out any non-online cpus from the cpumask after
validating any required semantics of the cpu set.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c
index 38ac189..7db8893 100644 (file)
--- a/arch/tile/kernel/hardwall.c
+++ b/arch/tile/kernel/hardwall.c
@@ -540,6 +540,14 @@ static struct hardwall_info *hardwall_create(struct hardwall_type *hwt,
                }
        }
 
+       /*
+        * Eliminate cpus that are not part of this Linux client.
+        * Note that this allows for configurations that we might not want to
+        * support, such as one client on every even cpu, another client on
+        * every odd cpu.
+        */
+       cpumask_and(&info->cpumask, &info->cpumask, cpu_online_mask);
+
        /* Confirm it doesn't overlap and add it to the list. */
        spin_lock_irqsave(&hwt->lock, flags);
        list_for_each_entry(iter, &hwt->list, list) {
@@ -612,7 +620,7 @@ static int hardwall_activate(struct hardwall_info *info)
 
 /*
  * Deactivate a task's hardwall.  Must hold lock for hardwall_type.
- * This method may be called from free_task(), so we don't want to
+ * This method may be called from exit_thread(), so we don't want to
  * rely on too many fields of struct task_struct still being valid.
  * We assume the cpus_allowed, pid, and comm fields are still valid.
  */

diff --git a/arch/tile/kernel/process.c b/arch/tile/kernel/process.c
index 8ac3044..8d6c51d 100644 (file)
--- a/arch/tile/kernel/process.c
+++ b/arch/tile/kernel/process.c
@@ -74,19 +74,6 @@ void arch_release_thread_info(struct thread_info *info)
 {
        struct single_step_state *step_state = info->step_state;
 
-#ifdef CONFIG_HARDWALL
-       /*
-        * We free a thread_info from the context of the task that has
-        * been scheduled next, so the original task is already dead.
-        * Calling deactivate here just frees up the data structures.
-        * If the task we're freeing held the last reference to a
-        * hardwall fd, it would have been released prior to this point
-        * anyway via exit_files(), and the hardwall_task.info pointers
-        * would be NULL by now.
-        */
-       hardwall_deactivate_all(info->task);
-#endif
-
        if (step_state) {
 
                /*
@@ -564,7 +551,15 @@ void flush_thread(void)
  */
 void exit_thread(void)
 {
-       /* Nothing */
+#ifdef CONFIG_HARDWALL
+       /*
+        * Remove the task from the list of tasks that are associated
+        * with any live hardwalls.  (If the task that is exiting held
+        * the last reference to a hardwall fd, it would already have
+        * been released and deactivated at this point.)
+        */
+       hardwall_deactivate_all(current);
+#endif
 }
 
 void show_regs(struct pt_regs *regs)