futex: add helper to find the top prio waiter of a futex (4b1c486b) · Commits · 戴 / test

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>

kernel/futex.c

+19 −0

Original line number	Diff line number	Diff line
		@@ -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;

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