netdev - [patch V3 11/20] rcuwait: Add @state argument to rcuwait_wait

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Date:   Sat, 21 Mar 2020 12:25:55 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Sebastian Siewior <bigeasy@...utronix.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Davidlohr Bueso <dave@...olabs.net>,
        Logan Gunthorpe <logang@...tatee.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Kurt Schwemmer <kurt.schwemmer@...rosemi.com>,
        linux-pci@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>, linux-usb@...r.kernel.org,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S. Miller" <davem@...emloft.net>,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        platform-driver-x86@...r.kernel.org,
        Zhang Rui <rui.zhang@...el.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        linux-pm@...r.kernel.org, Len Brown <lenb@...nel.org>,
        linux-acpi@...r.kernel.org, kbuild test robot <lkp@...el.com>,
        Nick Hu <nickhu@...estech.com>,
        Greentime Hu <green.hu@...il.com>,
        Vincent Chen <deanbo422@...il.com>,
        Guo Ren <guoren@...nel.org>, linux-csky@...r.kernel.org,
        Brian Cain <bcain@...eaurora.org>,
        linux-hexagon@...r.kernel.org, Tony Luck <tony.luck@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>, linux-ia64@...r.kernel.org,
        Michal Simek <monstr@...str.eu>,
        Michael Ellerman <mpe@...erman.id.au>,
        Arnd Bergmann <arnd@...db.de>,
        Geoff Levand <geoff@...radead.org>,
        linuxppc-dev@...ts.ozlabs.org,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Randy Dunlap <rdunlap@...radead.org>,
        Davidlohr Bueso <dbueso@...e.de>
Subject: [patch V3 11/20] rcuwait: Add @state argument to rcuwait_wait_event()

From: Peter Zijlstra (Intel) <peterz@...radead.org>

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Davidlohr Bueso <dave@...olabs.net>

---
 include/linux/rcuwait.h       |   12 ++++++++++--
 kernel/locking/percpu-rwsem.c |    2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)

--- 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 rcuwa
  * 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_ */
--- a/kernel/locking/percpu-rwsem.c
+++ b/kernel/locking/percpu-rwsem.c
@@ -162,7 +162,7 @@ void percpu_down_write(struct percpu_rw_
 	 */
 
 	/* Wait for all now 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);