Better procfs error handling and plugin activation locking.

1 files changed, 49 insertions, 27 deletions

diff --git a/litmus/sched_mc_ce.c b/litmus/sched_mc_ce.c
index 8ed960c8729c..1fdca7a7d3aa 100644
--- a/litmus/sched_mc_ce.c
+++ b/litmus/sched_mc_ce.c
@@ -31,6 +31,7 @@ static struct sched_plugin mc_ce_plugin __cacheline_aligned_in_smp;
 static atomic_t start_time_set = ATOMIC_INIT(0);
 static atomic64_t start_time = ATOMIC64_INIT(0);
 static struct proc_dir_entry *mc_ce_dir = NULL, *ce_file = NULL;
+static DEFINE_RAW_SPINLOCK(activate_lock);
 
 /*
  * Cache the budget along with the struct PID for a task so that we don't need
@@ -430,6 +431,8 @@ static long mc_ce_activate_plugin(void)
         domain_t *dom;
         int cpu;
 
+        raw_spin_lock(&activate_lock);
+
         for_each_online_cpu(cpu) {
                 dom = &per_cpu(mc_ce_doms, cpu);
                 ce_data = dom->data;
@@ -440,9 +443,34 @@ static long mc_ce_activate_plugin(void)
         atomic_set(&start_time_set, 0);
         atomic64_set(&start_time, litmus_clock());
         arm_all_timers();
+        raw_spin_unlock(&activate_lock);
         return 0;
 }
 
+static void clear_pid_entries(void)
+{
+        int cpu, entry;
+        domain_t *dom;
+        struct ce_dom_data *ce_data;
+
+        for_each_online_cpu(cpu) {
+                dom = &per_cpu(mc_ce_doms, cpu);
+                ce_data = dom->data;
+                ce_data->num_pid_entries = 0;
+                ce_data->cycle_time = 0;
+                for (entry = 0; entry < CONFIG_PLUGIN_MC_LEVEL_A_MAX_TASKS;
+                                ++entry) {
+                        if (NULL != ce_data->pid_entries[entry].pid) {
+                                put_pid(ce_data->pid_entries[entry].pid);
+                                ce_data->pid_entries[entry].pid = NULL;
+                        }
+                        ce_data->pid_entries[entry].exec_cost = 0;
+                        ce_data->pid_entries[entry].acc_time = 0;
+                }
+        }
+}
+
+static void tear_down_proc(void);
 static long mc_ce_deactivate_plugin(void)
 {
         domain_t *dom;
@@ -456,6 +484,8 @@ static long mc_ce_deactivate_plugin(void)
                 atomic_set(&ce_data->timer_info.state,
                                 HRTIMER_START_ON_INACTIVE);
         }
+        clear_pid_entries();
+        tear_down_proc();
         return 0;
 }
 
@@ -476,31 +506,7 @@ static struct sched_plugin mc_ce_plugin __cacheline_aligned_in_smp = {
         .deactivate_plugin      = mc_ce_deactivate_plugin,
 };
 
-static void clear_pid_entries(void)
-{
-        int cpu, entry;
-        domain_t *dom;
-        struct ce_dom_data *ce_data;
-
-        for_each_online_cpu(cpu) {
-                dom = &per_cpu(mc_ce_doms, cpu);
-                ce_data = dom->data;
-                ce_data->num_pid_entries = 0;
-                ce_data->cycle_time = 0;
-                for (entry = 0; entry < CONFIG_PLUGIN_MC_LEVEL_A_MAX_TASKS;
-                                ++entry) {
-                        if (NULL != ce_data->pid_entries[entry].pid) {
-                                put_pid(ce_data->pid_entries[entry].pid);
-                                ce_data->pid_entries[entry].pid = NULL;
-                        }
-                        ce_data->pid_entries[entry].exec_cost = 0;
-                        ce_data->pid_entries[entry].acc_time = 0;
-                }
-        }
-}
-
 static int setup_proc(void);
-
 static int __init init_sched_mc_ce(void)
 {
         struct ce_dom_data *ce_data;
@@ -510,7 +516,7 @@ static int __init init_sched_mc_ce(void)
         clear_pid_entries();
         for_each_online_cpu(cpu) {
                 dom = &per_cpu(mc_ce_doms, cpu);
-                pd_domain_init(dom, NULL, NULL, NULL, NULL);
+                pd_domain_init(dom, NULL, NULL, NULL, NULL, NULL);
                 dom->data = &per_cpu(_mc_ce_dom_data, cpu);
                 ce_data = dom->data;
                 hrtimer_init(&ce_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
@@ -711,6 +717,8 @@ static int proc_write_ce_file(struct file *file, const char __user *buffer,
         int cpu, task, cnt = 0, chars_read, converted, err;
         lt_t budget;
 
+        raw_spin_lock(&activate_lock);
+
         if (is_active_plugin()) {
                 printk(KERN_INFO "litmus: can't edit MC-CE proc when plugin "
                                 "active\n");
@@ -757,10 +765,20 @@ static int proc_write_ce_file(struct file *file, const char __user *buffer,
                 }
         }
 out:
+        raw_spin_unlock(&activate_lock);
         return cnt;
 }
 #undef PROCFS_MAX_SIZE
 
+#define CE_FILE_PROC_NAME "ce_file"
+static void tear_down_proc(void)
+{
+        if (ce_file)
+                remove_proc_entry(CE_FILE_PROC_NAME, mc_ce_dir);
+        if (mc_ce_dir)
+                remove_plugin_proc_dir(&mc_ce_plugin);
+}
+
 static int setup_proc(void)
 {
         int err;
@@ -769,16 +787,20 @@ static int setup_proc(void)
                 printk(KERN_ERR "could not create MC-CE procfs dir.\n");
                 goto out;
         }
-        ce_file = create_proc_entry("ce_file", 0644, mc_ce_dir);
+        ce_file = create_proc_entry(CE_FILE_PROC_NAME, 0644, mc_ce_dir);
         if (!ce_file) {
                 printk(KERN_ERR "could not create MC-CE procfs file.\n");
                 err = -EIO;
-                goto out;
+                goto out_remove_proc;
         }
         ce_file->read_proc = proc_read_ce_file;
         ce_file->write_proc = proc_write_ce_file;
+        goto out;
+out_remove_proc:
+        tear_down_proc();
 out:
         return err;
 }
+#undef CE_FILE_PROC_NAME
 
 module_init(init_sched_mc_ce);