Don't use tq->tq_lock_flags

The flags argument in spin_lock_irqsave is modified out side of spin_lock
context. We cannot use a shared variable like tq->tq_lock_flags for them. This
patch removes it and uses local variable for the flags.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #506

diff --git a/include/sys/taskq.h b/include/sys/taskq.h
index 5830fe2dd1b3cd9d90a71ef929c38f1bd3c93e93..07b4209e608d2561c999f2a1ffeb6dbd28d69b86 100644 (file)
--- a/include/sys/taskq.h
+++ b/include/sys/taskq.h
@@ -68,7 +68,6 @@ typedef void (task_func_t)(void *);
 
 typedef struct taskq {
        spinlock_t              tq_lock;       /* protects taskq_t */
-       unsigned long           tq_lock_flags; /* interrupt state */
        char                    *tq_name;      /* taskq name */
        struct list_head        tq_thread_list;/* list of all threads */
        struct list_head        tq_active_list;/* list of active threads */

diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c
index 588dbc8a4044b52e1d2ec3b1fe8e012b2ce73076..ded6d3b80c70114b18ee2521cfe4761aae8805ca 100644 (file)
--- a/module/spl/spl-taskq.c
+++ b/module/spl/spl-taskq.c
@@ -71,7 +71,7 @@ task_km_flags(uint_t flags)
  * is not attached to the free, work, or pending taskq lists.
  */
 static taskq_ent_t *
-task_alloc(taskq_t *tq, uint_t flags)
+task_alloc(taskq_t *tq, uint_t flags, unsigned long *irqflags)
 {
        taskq_ent_t *t;
        int count = 0;
@@ -111,9 +111,9 @@ retry:
                 * end up delaying the task allocation by one second, thereby
                 * throttling the task dispatch rate.
                 */
-               spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+               spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
                schedule_timeout(HZ / 100);
-               spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
+               spin_lock_irqsave_nested(&tq->tq_lock, *irqflags,
                    tq->tq_lock_class);
                if (count < 100) {
                        count++;
@@ -121,10 +121,9 @@ retry:
                }
        }
 
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, *irqflags);
        t = kmem_alloc(sizeof(taskq_ent_t), task_km_flags(flags));
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, *irqflags, tq->tq_lock_class);
 
        if (t) {
                taskq_init_ent(t);
@@ -189,13 +188,13 @@ task_expire(unsigned long data)
        taskq_ent_t *w, *t = (taskq_ent_t *)data;
        taskq_t *tq = t->tqent_taskq;
        struct list_head *l;
+       unsigned long flags;
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
 
        if (t->tqent_flags & TQENT_FLAG_CANCEL) {
                ASSERT(list_empty(&t->tqent_list));
-               spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+               spin_unlock_irqrestore(&tq->tq_lock, flags);
                return;
        }
 
@@ -214,7 +213,7 @@ task_expire(unsigned long data)
        if (l == &tq->tq_prio_list)
                list_add(&t->tqent_list, &tq->tq_prio_list);
 
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        wake_up(&tq->tq_work_waitq);
 }
@@ -381,11 +380,11 @@ taskq_wait_id_check(taskq_t *tq, taskqid_t id)
 {
        int active = 0;
        int rc;
+       unsigned long flags;
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        rc = (taskq_find(tq, id, &active) == NULL);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        return (rc);
 }
@@ -405,11 +404,11 @@ static int
 taskq_wait_outstanding_check(taskq_t *tq, taskqid_t id)
 {
        int rc;
+       unsigned long flags;
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        rc = (id < tq->tq_lowest_id);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        return (rc);
 }
@@ -433,11 +432,11 @@ static int
 taskq_wait_check(taskq_t *tq)
 {
        int rc;
+       unsigned long flags;
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        rc = (tq->tq_lowest_id == tq->tq_next_id);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        return (rc);
 }
@@ -479,11 +478,11 @@ int
 taskq_member(taskq_t *tq, void *t)
 {
        int found;
+       unsigned long flags;
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        found = taskq_member_impl(tq, t);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        return (found);
 }
@@ -501,11 +500,11 @@ taskq_cancel_id(taskq_t *tq, taskqid_t id)
        taskq_ent_t *t;
        int active = 0;
        int rc = ENOENT;
+       unsigned long flags;
 
        ASSERT(tq);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        t = taskq_find(tq, id, &active);
        if (t && !active) {
                list_del_init(&t->tqent_list);
@@ -525,10 +524,10 @@ taskq_cancel_id(taskq_t *tq, taskqid_t id)
                 * drop the lock before synchronously cancelling the timer.
                 */
                if (timer_pending(&t->tqent_timer)) {
-                       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+                       spin_unlock_irqrestore(&tq->tq_lock, flags);
                        del_timer_sync(&t->tqent_timer);
-                       spin_lock_irqsave_nested(&tq->tq_lock,
-                           tq->tq_lock_flags, tq->tq_lock_class);
+                       spin_lock_irqsave_nested(&tq->tq_lock, flags,
+                           tq->tq_lock_class);
                }
 
                if (!(t->tqent_flags & TQENT_FLAG_PREALLOC))
@@ -536,7 +535,7 @@ taskq_cancel_id(taskq_t *tq, taskqid_t id)
 
                rc = 0;
        }
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        if (active) {
                taskq_wait_id(tq, id);
@@ -554,12 +553,12 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
 {
        taskq_ent_t *t;
        taskqid_t rc = 0;
+       unsigned long irqflags;
 
        ASSERT(tq);
        ASSERT(func);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
 
        /* Taskq being destroyed and all tasks drained */
        if (!(tq->tq_flags & TASKQ_ACTIVE))
@@ -570,7 +569,7 @@ taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
        if ((flags & TQ_NOQUEUE) && (tq->tq_nactive == tq->tq_nthreads))
                goto out;
 
-       if ((t = task_alloc(tq, flags)) == NULL)
+       if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
                goto out;
 
        spin_lock(&t->tqent_lock);
@@ -600,7 +599,7 @@ out:
        if (tq->tq_nactive == tq->tq_nthreads)
                (void) taskq_thread_spawn(tq);
 
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, irqflags);
        return (rc);
 }
 EXPORT_SYMBOL(taskq_dispatch);
@@ -611,18 +610,18 @@ taskq_dispatch_delay(taskq_t *tq, task_func_t func, void *arg,
 {
        taskqid_t rc = 0;
        taskq_ent_t *t;
+       unsigned long irqflags;
 
        ASSERT(tq);
        ASSERT(func);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, irqflags, tq->tq_lock_class);
 
        /* Taskq being destroyed and all tasks drained */
        if (!(tq->tq_flags & TASKQ_ACTIVE))
                goto out;
 
-       if ((t = task_alloc(tq, flags)) == NULL)
+       if ((t = task_alloc(tq, flags, &irqflags)) == NULL)
                goto out;
 
        spin_lock(&t->tqent_lock);
@@ -647,7 +646,7 @@ out:
        /* Spawn additional taskq threads if required. */
        if (tq->tq_nactive == tq->tq_nthreads)
                (void) taskq_thread_spawn(tq);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, irqflags);
        return (rc);
 }
 EXPORT_SYMBOL(taskq_dispatch_delay);
@@ -656,10 +655,11 @@ void
 taskq_dispatch_ent(taskq_t *tq, task_func_t func, void *arg, uint_t flags,
    taskq_ent_t *t)
 {
+       unsigned long irqflags;
        ASSERT(tq);
        ASSERT(func);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
+       spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
            tq->tq_lock_class);
 
        /* Taskq being destroyed and all tasks drained */
@@ -695,7 +695,7 @@ out:
        /* Spawn additional taskq threads if required. */
        if (tq->tq_nactive == tq->tq_nthreads)
                (void) taskq_thread_spawn(tq);
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, irqflags);
 }
 EXPORT_SYMBOL(taskq_dispatch_ent);
 
@@ -749,13 +749,13 @@ static void
 taskq_thread_spawn_task(void *arg)
 {
        taskq_t *tq = (taskq_t *)arg;
+       unsigned long flags;
 
        (void) taskq_thread_create(tq);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        tq->tq_nspawn--;
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 }
 
 /*
@@ -821,6 +821,7 @@ taskq_thread(void *args)
        taskq_t *tq;
        taskq_ent_t *t;
        int seq_tasks = 0;
+       unsigned long flags;
 
        ASSERT(tqt);
        ASSERT(tqt->tqt_tq);
@@ -835,8 +836,7 @@ taskq_thread(void *args)
        sigprocmask(SIG_BLOCK, &blocked, NULL);
        flush_signals(current);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
 
        /* Immediately exit if more threads than allowed were created. */
        if (tq->tq_nthreads >= tq->tq_maxthreads)
@@ -858,13 +858,13 @@ taskq_thread(void *args)
                        }
 
                        add_wait_queue_exclusive(&tq->tq_work_waitq, &wait);
-                       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+                       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
                        schedule();
                        seq_tasks = 0;
 
-                       spin_lock_irqsave_nested(&tq->tq_lock,
-                           tq->tq_lock_flags, tq->tq_lock_class);
+                       spin_lock_irqsave_nested(&tq->tq_lock, flags,
+                           tq->tq_lock_class);
                        remove_wait_queue(&tq->tq_work_waitq, &wait);
                } else {
                        __set_current_state(TASK_RUNNING);
@@ -888,13 +888,13 @@ taskq_thread(void *args)
 
                        taskq_insert_in_order(tq, tqt);
                        tq->tq_nactive++;
-                       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+                       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
                        /* Perform the requested task */
                        t->tqent_func(t->tqent_arg);
 
-                       spin_lock_irqsave_nested(&tq->tq_lock,
-                           tq->tq_lock_flags, tq->tq_lock_class);
+                       spin_lock_irqsave_nested(&tq->tq_lock, flags,
+                           tq->tq_lock_class);
                        tq->tq_nactive--;
                        list_del_init(&tqt->tqt_active_list);
                        tqt->tqt_task = NULL;
@@ -932,7 +932,7 @@ taskq_thread(void *args)
        list_del_init(&tqt->tqt_thread_list);
 error:
        kmem_free(tqt, sizeof (taskq_thread_t));
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        return (0);
 }
@@ -976,6 +976,7 @@ taskq_create(const char *name, int nthreads, pri_t pri,
        taskq_t *tq;
        taskq_thread_t *tqt;
        int count = 0, rc = 0, i;
+       unsigned long irqflags;
 
        ASSERT(name != NULL);
        ASSERT(minalloc >= 0);
@@ -1019,13 +1020,14 @@ taskq_create(const char *name, int nthreads, pri_t pri,
        tq->tq_lock_class = TQ_LOCK_GENERAL;
 
        if (flags & TASKQ_PREPOPULATE) {
-               spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
+               spin_lock_irqsave_nested(&tq->tq_lock, irqflags,
                    tq->tq_lock_class);
 
                for (i = 0; i < minalloc; i++)
-                       task_done(tq, task_alloc(tq, TQ_PUSHPAGE | TQ_NEW));
+                       task_done(tq, task_alloc(tq, TQ_PUSHPAGE | TQ_NEW,
+                           &irqflags));
 
-               spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+               spin_unlock_irqrestore(&tq->tq_lock, irqflags);
        }
 
        if ((flags & TASKQ_DYNAMIC) && spl_taskq_thread_dynamic)
@@ -1057,12 +1059,12 @@ taskq_destroy(taskq_t *tq)
        struct task_struct *thread;
        taskq_thread_t *tqt;
        taskq_ent_t *t;
+       unsigned long flags;
 
        ASSERT(tq);
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
        tq->tq_flags &= ~TASKQ_ACTIVE;
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        /*
         * When TASKQ_ACTIVE is clear new tasks may not be added nor may
@@ -1073,8 +1075,7 @@ taskq_destroy(taskq_t *tq)
 
        taskq_wait(tq);
 
-       spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
-           tq->tq_lock_class);
+       spin_lock_irqsave_nested(&tq->tq_lock, flags, tq->tq_lock_class);
 
        /*
         * Signal each thread to exit and block until it does.  Each thread
@@ -1086,11 +1087,11 @@ taskq_destroy(taskq_t *tq)
                tqt = list_entry(tq->tq_thread_list.next,
                    taskq_thread_t, tqt_thread_list);
                thread = tqt->tqt_thread;
-               spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+               spin_unlock_irqrestore(&tq->tq_lock, flags);
 
                kthread_stop(thread);
 
-               spin_lock_irqsave_nested(&tq->tq_lock, tq->tq_lock_flags,
+               spin_lock_irqsave_nested(&tq->tq_lock, flags,
                    tq->tq_lock_class);
        }
 
@@ -1113,7 +1114,7 @@ taskq_destroy(taskq_t *tq)
        ASSERT(list_empty(&tq->tq_prio_list));
        ASSERT(list_empty(&tq->tq_delay_list));
 
-       spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags);
+       spin_unlock_irqrestore(&tq->tq_lock, flags);
 
        strfree(tq->tq_name);
        kmem_free(tq, sizeof (taskq_t));