From: Henrik Austad <henrik@austad.us>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Henrik Austad <haustad@cisco.com>,
Peter Zijlstra <peterz@infradead.org>,
juri.lelli@arm.com, bigeasy@linutronix.de, xlpang@redhat.com,
rostedt@goodmis.org, mathieu.desnoyers@efficios.com,
jdesfossez@efficios.com, dvhart@infradead.org,
bristot@redhat.com, Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 01/17] futex: Cleanup variable names for futex_top_waiter()
Date: Fri, 9 Nov 2018 11:07:29 +0100 [thread overview]
Message-ID: <1541758065-10952-2-git-send-email-henrik@austad.us> (raw)
In-Reply-To: <1541758065-10952-1-git-send-email-henrik@austad.us>
From: Peter Zijlstra <peterz@infradead.org>
commit 499f5aca2cdd5e958b27e2655e7e7f82524f46b1 uptream.
futex_top_waiter() returns the top-waiter on the pi_mutex. Assinging
this to a variable 'match' totally obscures the code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170322104151.554710645@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Henrik Austad <haustad@cisco.com>
---
kernel/futex.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index a26d217..bb87324 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1116,14 +1116,14 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key,
static int lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
union futex_key *key, struct futex_pi_state **ps)
{
- struct futex_q *match = futex_top_waiter(hb, key);
+ struct futex_q *top_waiter = futex_top_waiter(hb, key);
/*
* If there is a waiter on that futex, validate it and
* attach to the pi_state when the validation succeeds.
*/
- if (match)
- return attach_to_pi_state(uval, match->pi_state, ps);
+ if (top_waiter)
+ return attach_to_pi_state(uval, top_waiter->pi_state, ps);
/*
* We are the first waiter - try to look up the owner based on
@@ -1170,7 +1170,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
struct task_struct *task, int set_waiters)
{
u32 uval, newval, vpid = task_pid_vnr(task);
- struct futex_q *match;
+ struct futex_q *top_waiter;
int ret;
/*
@@ -1196,9 +1196,9 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
* Lookup existing state first. If it exists, try to attach to
* its pi_state.
*/
- match = futex_top_waiter(hb, key);
- if (match)
- return attach_to_pi_state(uval, match->pi_state, ps);
+ top_waiter = futex_top_waiter(hb, key);
+ if (top_waiter)
+ return attach_to_pi_state(uval, top_waiter->pi_state, ps);
/*
* No waiter and user TID is 0. We are here because the
@@ -1288,11 +1288,11 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q)
q->lock_ptr = NULL;
}
-static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this,
+static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *top_waiter,
struct futex_hash_bucket *hb)
{
struct task_struct *new_owner;
- struct futex_pi_state *pi_state = this->pi_state;
+ struct futex_pi_state *pi_state = top_waiter->pi_state;
u32 uninitialized_var(curval), newval;
WAKE_Q(wake_q);
bool deboost;
@@ -1313,11 +1313,11 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this,
/*
* It is possible that the next waiter (the one that brought
- * this owner to the kernel) timed out and is no longer
+ * top_waiter owner to the kernel) timed out and is no longer
* waiting on the lock.
*/
if (!new_owner)
- new_owner = this->task;
+ new_owner = top_waiter->task;
/*
* We pass it to the next owner. The WAITERS bit is always
@@ -2639,7 +2639,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
u32 uninitialized_var(curval), uval, vpid = task_pid_vnr(current);
union futex_key key = FUTEX_KEY_INIT;
struct futex_hash_bucket *hb;
- struct futex_q *match;
+ struct futex_q *top_waiter;
int ret;
retry:
@@ -2663,9 +2663,9 @@ retry:
* all and we at least want to know if user space fiddled
* with the futex value instead of blindly unlocking.
*/
- match = futex_top_waiter(hb, &key);
- if (match) {
- ret = wake_futex_pi(uaddr, uval, match, hb);
+ top_waiter = futex_top_waiter(hb, &key);
+ if (top_waiter) {
+ ret = wake_futex_pi(uaddr, uval, top_waiter, hb);
/*
* In case of success wake_futex_pi dropped the hash
* bucket lock.
--
2.7.4
next prev parent reply other threads:[~2018-11-09 10:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-09 10:07 [PATCH 00/17] Backport rt/deadline crash and the ardous story of FUTEX_UNLOCK_PI to 4.4 Henrik Austad
2018-11-09 10:07 ` Henrik Austad [this message]
2018-11-09 10:07 ` [PATCH 02/17] futex: Use smp_store_release() in mark_wake_futex() Henrik Austad
2018-11-09 10:07 ` [PATCH 03/17] futex: Remove rt_mutex_deadlock_account_*() Henrik Austad
2018-11-09 10:07 ` [PATCH 04/17] rtmutex: Make wait_lock irq safe Henrik Austad
2018-11-09 10:07 ` [PATCH 05/17] futex,rt_mutex: Provide futex specific rt_mutex API Henrik Austad
2018-11-09 10:07 ` [PATCH 06/17] futex: Change locking rules Henrik Austad
2018-11-09 10:07 ` [PATCH 07/17] futex: Cleanup refcounting Henrik Austad
2018-11-09 10:07 ` [PATCH 08/17] futex: Rework inconsistent rt_mutex/futex_q state Henrik Austad
2018-11-09 10:07 ` [PATCH 09/17] futex: Rename free_pi_state() to put_pi_state() Henrik Austad
2018-11-09 10:07 ` [PATCH 10/17] futex: Pull rt_mutex_futex_unlock() out from under hb->lock Henrik Austad
2018-11-09 10:07 ` [PATCH 11/17] futex,rt_mutex: Introduce rt_mutex_init_waiter() Henrik Austad
2018-11-09 10:07 ` [PATCH 12/17] futex,rt_mutex: Restructure rt_mutex_finish_proxy_lock() Henrik Austad
2018-11-09 10:07 ` [PATCH 13/17] futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock() Henrik Austad
2018-11-09 10:07 ` [PATCH 14/17] futex: Futex_unlock_pi() determinism Henrik Austad
2018-11-09 10:07 ` [PATCH 15/17] futex: Drop hb->lock before enqueueing on the rtmutex Henrik Austad
2018-11-09 10:07 ` [PATCH 16/17] rtmutex: Deboost before waking up the top waiter Henrik Austad
2018-11-09 10:07 ` [PATCH 17/17] sched/rtmutex/deadline: Fix a PI crash for deadline tasks Henrik Austad
2018-11-09 10:35 ` [PATCH 00/17] Backport rt/deadline crash and the ardous story of FUTEX_UNLOCK_PI to 4.4 Henrik Austad
2018-11-19 11:27 ` Henrik Austad
2018-12-14 7:18 ` Greg Kroah-Hartman
2018-12-14 7:36 ` Henrik Austad
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