[tip:core/locking] futexes: Clean up various details

tip-bot for Jason Low
2014-01-13T15:53:47Z

Commit-ID: 0d00c7b20c7716ce08399570ea48813ecf001aa8
Gitweb: http://git.kernel.org/tip/0d00c7b20c7716ce08399570ea48813ecf001aa8
Author: Jason Low <jason.low2@hp.com>
AuthorDate: Sun, 12 Jan 2014 15:31:22 -0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 13 Jan 2014 11:45:17 +0100

futexes: Clean up various details

- Remove unnecessary head variables.
- Delete unused parameter in queue_unlock().

Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Scott Norton <scott.norton@hp.com>
Cc: Tom Vaden <tom.vaden@hp.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1389569486-25487-2-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/futex.c | 39 ++++++++++++---------------------------
1 file changed, 12 insertions(+), 27 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index f6ff019..085f5fa 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -598,13 +598,10 @@ lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
{
struct futex_pi_state *pi_state = NULL;
struct futex_q *this, *next;
- struct plist_head *head;
struct task_struct *p;
pid_t pid = uval & FUTEX_TID_MASK;

- head = &hb->chain;
-
- plist_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, &hb->chain, list) {
if (match_futex(&this->key, key)) {
/*
* Another waiter already exists - bump up
@@ -986,7 +983,6 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
- struct plist_head *head;
union futex_key key = FUTEX_KEY_INIT;
int ret;

@@ -999,9 +995,8 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)

hb = hash_futex(&key);
spin_lock(&hb->lock);
- head = &hb->chain;

- plist_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, &hb->chain, list) {
if (match_futex (&this->key, &key)) {
if (this->pi_state || this->rt_waiter) {
ret = -EINVAL;
@@ -1034,7 +1029,6 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
{
union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
struct futex_hash_bucket *hb1, *hb2;
- struct plist_head *head;
struct futex_q *this, *next;
int ret, op_ret;

@@ -1082,9 +1076,7 @@ retry_private:
goto retry;
}

- head = &hb1->chain;
-
- plist_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, &hb1->chain, list) {
if (match_futex (&this->key, &key1)) {
if (this->pi_state || this->rt_waiter) {
ret = -EINVAL;
@@ -1097,10 +1089,8 @@ retry_private:
}

if (op_ret > 0) {
- head = &hb2->chain;
-
op_ret = 0;
- plist_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, &hb2->chain, list) {
if (match_futex (&this->key, &key2)) {
if (this->pi_state || this->rt_waiter) {
ret = -EINVAL;
@@ -1270,7 +1260,6 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
int drop_count = 0, task_count = 0, ret;
struct futex_pi_state *pi_state = NULL;
struct futex_hash_bucket *hb1, *hb2;
- struct plist_head *head1;
struct futex_q *this, *next;
u32 curval2;

@@ -1393,8 +1382,7 @@ retry_private:
}
}

- head1 = &hb1->chain;
- plist_for_each_entry_safe(this, next, head1, list) {
+ plist_for_each_entry_safe(this, next, &hb1->chain, list) {
if (task_count - nr_wake >= nr_requeue)
break;

@@ -1494,7 +1482,7 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)
}

static inline void
-queue_unlock(struct futex_q *q, struct futex_hash_bucket *hb)
+queue_unlock(struct futex_hash_bucket *hb)
__releases(&hb->lock)
{
spin_unlock(&hb->lock);
@@ -1867,7 +1855,7 @@ retry_private:
ret = get_futex_value_locked(&uval, uaddr);

if (ret) {
- queue_unlock(q, *hb);
+ queue_unlock(*hb);

ret = get_user(uval, uaddr);
if (ret)
@@ -1881,7 +1869,7 @@ retry_private:
}

if (uval != val) {
- queue_unlock(q, *hb);
+ queue_unlock(*hb);
ret = -EWOULDBLOCK;
}

@@ -2029,7 +2017,7 @@ retry_private:
* Task is exiting and we just wait for the
* exit to complete.
*/
- queue_unlock(&q, hb);
+ queue_unlock(hb);
put_futex_key(&q.key);
cond_resched();
goto retry;
@@ -2081,7 +2069,7 @@ retry_private:
goto out_put_key;

out_unlock_put_key:
- queue_unlock(&q, hb);
+ queue_unlock(hb);

out_put_key:
put_futex_key(&q.key);
@@ -2091,7 +2079,7 @@ out:
return ret != -EINTR ? ret : -ERESTARTNOINTR;

uaddr_faulted:
- queue_unlock(&q, hb);
+ queue_unlock(hb);

ret = fault_in_user_writeable(uaddr);
if (ret)
@@ -2113,7 +2101,6 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
- struct plist_head *head;
union futex_key key = FUTEX_KEY_INIT;
u32 uval, vpid = task_pid_vnr(current);
int ret;
@@ -2153,9 +2140,7 @@ retry:
* Ok, other tasks may need to be woken up - check waiters
* and do the wakeup if necessary:
*/
- head = &hb->chain;
-
- plist_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, &hb->chain, list) {
if (!match_futex (&this->key, &key))
continue;
ret = wake_futex_pi(uaddr, uval, this);