rcuwait: Add @state argument to rcuwait_wait_event()

Extend rcuwait_wait_event() with a state variable so that it is not
restricted to UNINTERRUPTIBLE waits.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113241.824030968@linutronix.de

diff --git a/include/linux/rcuwait.h b/include/linux/rcuwait.h
index 75c97e4..2ffe1ee 100644 (file)
--- a/include/linux/rcuwait.h
+++ b/include/linux/rcuwait.h
@@ -3,6 +3,7 @@
 #define _LINUX_RCUWAIT_H_
 
 #include <linux/rcupdate.h>
+#include <linux/sched/signal.h>
 
 /*
  * rcuwait provides a way of blocking and waking up a single
@@ -30,23 +31,30 @@ extern void rcuwait_wake_up(struct rcuwait *w);
  * The caller is responsible for locking around rcuwait_wait_event(),
  * such that writes to @task are properly serialized.
  */
-#define rcuwait_wait_event(w, condition)                               \
+#define rcuwait_wait_event(w, condition, state)                                \
 ({                                                                     \
+       int __ret = 0;                                                  \
        rcu_assign_pointer((w)->task, current);                         \
        for (;;) {                                                      \
                /*                                                      \
                 * Implicit barrier (A) pairs with (B) in               \
                 * rcuwait_wake_up().                                   \
                 */                                                     \
-               set_current_state(TASK_UNINTERRUPTIBLE);                \
+               set_current_state(state);                               \
                if (condition)                                          \
                        break;                                          \
                                                                        \
+               if (signal_pending_state(state, current)) {             \
+                       __ret = -EINTR;                                 \
+                       break;                                          \
+               }                                                       \
+                                                                       \
                schedule();                                             \
        }                                                               \
                                                                        \
        WRITE_ONCE((w)->task, NULL);                                    \
        __set_current_state(TASK_RUNNING);                              \
+       __ret;                                                          \
 })
 
 #endif /* _LINUX_RCUWAIT_H_ */

diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c
index 183a3aa..a008a1b 100644 (file)
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -234,7 +234,7 @@ void percpu_down_write(struct percpu_rw_semaphore *sem)
         */
 
        /* Wait for all active readers to complete. */
-       rcuwait_wait_event(&sem->writer, readers_active_check(sem));
+       rcuwait_wait_event(&sem->writer, readers_active_check(sem), TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(percpu_down_write);