linux-kernel - [PATCH 01/17] futex: Cleanup variable names for futex_top

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1541758065-10952-2-git-send-email-henrik@austad.us>
Date:   Fri,  9 Nov 2018 11:07:29 +0100
From:   Henrik Austad <henrik@...tad.us>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Henrik Austad <haustad@...co.com>,
        Peter Zijlstra <peterz@...radead.org>, juri.lelli@....com,
        bigeasy@...utronix.de, xlpang@...hat.com, rostedt@...dmis.org,
        mathieu.desnoyers@...icios.com, jdesfossez@...icios.com,
        dvhart@...radead.org, bristot@...hat.com,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 01/17] futex: Cleanup variable names for futex_top_waiter()

From: Peter Zijlstra <peterz@...radead.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@...radead.org>
Cc: juri.lelli@....com
Cc: bigeasy@...utronix.de
Cc: xlpang@...hat.com
Cc: rostedt@...dmis.org
Cc: mathieu.desnoyers@...icios.com
Cc: jdesfossez@...icios.com
Cc: dvhart@...radead.org
Cc: bristot@...hat.com
Link: http://lkml.kernel.org/r/20170322104151.554710645@infradead.org
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Tested-by: Henrik Austad <haustad@...co.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