From 4b1c486b3587d2abf50bee4a05eb488cd4045f2c Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Fri, 3 Apr 2009 13:39:42 -0700 Subject: [PATCH] futex: add helper to find the top prio waiter of a futex Improve legibility by wrapping finding the top waiter in a function. This will be used by the follow-on patches for enabling requeue pi. Signed-off-by: Darren Hart Reviewed-by: Thomas Gleixner Signed-off-by: Thomas Gleixner --- kernel/futex.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/kernel/futex.c b/kernel/futex.c index ebb48d6d1a8..421fb5e42a1 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -276,6 +276,25 @@ void put_futex_key(int fshared, union futex_key *key) drop_futex_key_refs(key); } +/** + * futex_top_waiter() - Return the highest priority waiter on a futex + * @hb: the hash bucket the futex_q's reside in + * @key: the futex key (to distinguish it from other futex futex_q's) + * + * Must be called with the hb lock held. + */ +static struct futex_q *futex_top_waiter(struct futex_hash_bucket *hb, + union futex_key *key) +{ + struct futex_q *this; + + plist_for_each_entry(this, &hb->chain, list) { + if (match_futex(&this->key, key)) + return this; + } + return NULL; +} + static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval) { u32 curval;