futex: Cleanup variable names for futex_top_waiter()

From: Peter Zijlstra <peterz@infradead.org>

commit 499f5aca2cdd5e958b27e2655e7e7f82524f46b1 upstream.

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>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/futex.c b/kernel/futex.c
index 0b49a8e1e1becc771822c178c6bd5f60c4b9ea10..1cb5064548d6c8d3c0bb8abcc64257e58e3aa01d 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1352,14 +1352,14 @@ static int lookup_pi_state(u32 __user *uaddr, u32 uval,
                           union futex_key *key, struct futex_pi_state **ps,
                           struct task_struct **exiting)
 {
-       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(uaddr, uval, match->pi_state, ps);
+       if (top_waiter)
+               return attach_to_pi_state(uaddr, uval, top_waiter->pi_state, ps);
 
        /*
         * We are the first waiter - try to look up the owner based on
@@ -1414,7 +1414,7 @@ static int futex_lock_pi_atomic(u32 __user *uaddr, struct futex_hash_bucket *hb,
                                int set_waiters)
 {
        u32 uval, newval, vpid = task_pid_vnr(task);
-       struct futex_q *match;
+       struct futex_q *top_waiter;
        int ret;
 
        /*
@@ -1440,9 +1440,9 @@ 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(uaddr, uval, match->pi_state, ps);
+       top_waiter = futex_top_waiter(hb, key);
+       if (top_waiter)
+               return attach_to_pi_state(uaddr, uval, top_waiter->pi_state, ps);
 
        /*
         * No waiter and user TID is 0. We are here because the
@@ -1532,11 +1532,11 @@ 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;
@@ -1557,7 +1557,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *this,
 
        /*
         * When we interleave with futex_lock_pi() where it does
-        * rt_mutex_timed_futex_lock(), we might observe @this futex_q waiter,
+        * rt_mutex_timed_futex_lock(), we might observe @top_waiter futex_q waiter,
         * but the rt_mutex's wait_list can be empty (either still, or again,
         * depending on which side we land).
         *
@@ -2975,7 +2975,7 @@ 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:
@@ -2999,9 +2999,9 @@ 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.