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Subject[PATCH 01/17] futex: Cleanup variable names for futex_top_waiter()
Date
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
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