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>

2 files changed, 18 insertions, 15 deletions

diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c
index 38ac189d9575..7db8893d4fc5 100644
--- 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 8ac304484f98..8d6c51d55762 100644
--- 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)