From: zanussi@kernel.org
To: LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Daniel Wagner <wagi@monom.org>, Tom Zanussi <zanussi@kernel.org>,
Julia Cartwright <julia@ni.com>
Subject: [PATCH RT 15/19] Revert "futex: workaround migrate_disable/enable in different context"
Date: Thu, 8 Aug 2019 14:52:43 -0500 [thread overview]
Message-ID: <6c551bd14ae69ce8bb8c99cf9d4cd0bafd3015ca.1565293935.git.zanussi@kernel.org> (raw)
In-Reply-To: <cover.1565293934.git.zanussi@kernel.org>
In-Reply-To: <cover.1565293934.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
v4.14.137-rt65-rc1 stable review patch.
If anyone has any objections, please let me know.
-----------
[ Upstream commit a71221d81cc4873891ae44f3aa02df596079b786 ]
Drop the RT fixup, the futex code will be changed to avoid the need for
the workaround.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Conflicts:
kernel/futex.c
---
kernel/futex.c | 19 -------------------
1 file changed, 19 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index cb7e212fba0f..ec90130cd809 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2893,14 +2893,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
* before __rt_mutex_start_proxy_lock() is done.
*/
raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
- /*
- * the migrate_disable() here disables migration in the in_atomic() fast
- * path which is enabled again in the following spin_unlock(). We have
- * one migrate_disable() pending in the slow-path which is reversed
- * after the raw_spin_unlock_irq() where we leave the atomic context.
- */
- migrate_disable();
-
spin_unlock(q.lock_ptr);
/*
* __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
@@ -2909,7 +2901,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
*/
ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
- migrate_enable();
if (ret) {
if (ret == 1)
@@ -3058,21 +3049,11 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
* rt_waiter. Also see the WARN in wake_futex_pi().
*/
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
- /*
- * Magic trickery for now to make the RT migrate disable
- * logic happy. The following spin_unlock() happens with
- * interrupts disabled so the internal migrate_enable()
- * won't undo the migrate_disable() which was issued when
- * locking hb->lock.
- */
- migrate_disable();
spin_unlock(&hb->lock);
/* drops pi_state->pi_mutex.wait_lock */
ret = wake_futex_pi(uaddr, uval, pi_state);
- migrate_enable();
-
put_pi_state(pi_state);
/*
--
2.14.1
next prev parent reply other threads:[~2019-08-08 19:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-08 19:52 [PATCH RT 00/19] Linux v4.14.137-rt65-rc1 zanussi
2019-08-08 19:52 ` [PATCH RT 01/19] kthread: Use __RAW_SPIN_LOCK_UNLOCK to initialize kthread_worker lock zanussi
2019-08-08 19:52 ` [PATCH RT 02/19] kthread: add a global worker thread zanussi
2019-08-08 19:52 ` [PATCH RT 03/19] genirq: Do not invoke the affinity callback via a workqueue on RT zanussi
2019-08-08 19:52 ` [PATCH RT 04/19] genirq: Handle missing work_struct in irq_set_affinity_notifier() zanussi
2019-08-08 19:52 ` [PATCH RT 05/19] locking/rwsem: Rename rwsem_rt.h to rwsem-rt.h zanussi
2019-08-08 19:52 ` [PATCH RT 06/19] sched/completion: Fix a lockup in wait_for_completion() zanussi
2019-08-08 19:52 ` [PATCH RT 07/19] locking/lockdep: Don't complain about incorrect name for no validate class zanussi
2019-08-08 19:52 ` [PATCH RT 08/19] arm: imx6: cpuidle: Use raw_spinlock_t zanussi
2019-08-08 19:52 ` [PATCH RT 09/19] rcu: Don't allow to change rcu_normal_after_boot on RT zanussi
2019-08-08 19:52 ` [PATCH RT 10/19] pci/switchtec: fix stream_open.cocci warnings zanussi
2019-08-08 19:52 ` [PATCH RT 11/19] sched/core: Drop a preempt_disable_rt() statement zanussi
2019-08-08 19:52 ` [PATCH RT 12/19] Revert "futex: Ensure lock/unlock symetry versus pi_lock and hash bucket lock" zanussi
2019-08-08 19:52 ` [PATCH RT 13/19] Revert "futex: Fix bug on when a requeued RT task times out" zanussi
2019-08-08 19:52 ` [PATCH RT 14/19] Revert "rtmutex: Handle the various new futex race conditions" zanussi
2019-08-08 19:52 ` zanussi [this message]
2019-08-08 19:52 ` [PATCH RT 16/19] futex: Make the futex_hash_bucket lock raw zanussi
2019-08-08 19:52 ` [PATCH RT 17/19] futex: Delay deallocation of pi_state zanussi
2019-08-08 19:52 ` [PATCH RT 18/19] mm/zswap: Do not disable preemption in zswap_frontswap_store() zanussi
2019-08-08 19:52 ` [PATCH RT 19/19] Linux 4.14.137-rt65-rc1 zanussi
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