1 files changed, 17 insertions, 21 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 8c548232ba39..4c69326aa773 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -781,7 +781,7 @@ static void wake_threads_waitq(struct irq_desc *desc)
                 wake_up(&desc->wait_for_threads);
 }
 
-static void irq_thread_dtor(struct task_work *unused)
+static void irq_thread_dtor(struct callback_head *unused)
 {
         struct task_struct *tsk = current;
         struct irq_desc *desc;
@@ -813,7 +813,7 @@ static void irq_thread_dtor(struct task_work *unused)
  */
 static int irq_thread(void *data)
 {
-        struct task_work on_exit_work;
+        struct callback_head on_exit_work;
         static const struct sched_param param = {
                 .sched_priority = MAX_USER_RT_PRIO/2,
         };
@@ -830,7 +830,7 @@ static int irq_thread(void *data)
 
         sched_setscheduler(current, SCHED_FIFO, &param);
 
-        init_task_work(&on_exit_work, irq_thread_dtor, NULL);
+        init_task_work(&on_exit_work, irq_thread_dtor);
         task_work_add(current, &on_exit_work, false);
 
         while (!irq_wait_for_interrupt(action)) {
@@ -893,22 +893,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                 return -ENOSYS;
         if (!try_module_get(desc->owner))
                 return -ENODEV;
-        /*
-         * Some drivers like serial.c use request_irq() heavily,
-         * so we have to be careful not to interfere with a
-         * running system.
-         */
-        if (new->flags & IRQF_SAMPLE_RANDOM) {
-                /*
-                 * This function might sleep, we want to call it first,
-                 * outside of the atomic block.
-                 * Yes, this might clear the entropy pool if the wrong
-                 * driver is attempted to be loaded, without actually
-                 * installing a new handler, but is this really a problem,
-                 * only the sysadmin is able to do this.
-                 */
-                rand_initialize_irq(irq);
-        }
 
         /*
          * Check whether the interrupt nests into another interrupt
@@ -960,6 +944,18 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
         }
 
         /*
+         * Drivers are often written to work w/o knowledge about the
+         * underlying irq chip implementation, so a request for a
+         * threaded irq without a primary hard irq context handler
+         * requires the ONESHOT flag to be set. Some irq chips like
+         * MSI based interrupts are per se one shot safe. Check the
+         * chip flags, so we can avoid the unmask dance at the end of
+         * the threaded handler for those.
+         */
+        if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
+                new->flags &= ~IRQF_ONESHOT;
+
+        /*
          * The following block of code has to be executed atomically
          */
         raw_spin_lock_irqsave(&desc->lock, flags);
@@ -1033,7 +1029,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  */
                 new->thread_mask = 1 << ffz(thread_mask);
 
-        } else if (new->handler == irq_default_primary_handler) {
+        } else if (new->handler == irq_default_primary_handler &&
+                   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
                 /*
                  * The interrupt was requested with handler = NULL, so
                  * we use the default primary handler for it. But it
@@ -1354,7 +1351,6 @@ EXPORT_SYMBOL(free_irq);
  *      Flags:
  *
  *      IRQF_SHARED             Interrupt is shared
- *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
  *      IRQF_TRIGGER_*          Specify active edge(s) or level
  *
  */