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author | Darren Hart <dvhltc@us.ibm.com> | 2009-04-03 20:39:42 (GMT) |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2009-04-06 09:14:01 (GMT) |
commit | 4b1c486b3587d2abf50bee4a05eb488cd4045f2c (patch) | |
tree | 17b2a04c34787cb8af37d8d73d27710a42b870de /kernel | |
parent | ca5f9524d61f54b1f618293ab92fc6b49cac864d (diff) | |
download | linux-4b1c486b3587d2abf50bee4a05eb488cd4045f2c.tar.xz |
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 <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/futex.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index ebb48d6..421fb5e 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; |