We want to be a bit more clever in futex_lock_pi_atomic() and separate
the possible states. Split out the code which attaches the first
waiter to the owner into a separate function. No functional change.
Signed-off-by: Thomas Gleixner
---
kernel/futex.c | 42 --
1 file changed, 28 insertions(+), 14 deletions(-)
Index: linux/kernel/futex.c
===
--- linux.orig/kernel/futex.c
+++ linux/kernel/futex.c
@@ -865,21 +865,16 @@ out_state:
return 0;
}
-static int
-lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
- union futex_key *key, struct futex_pi_state **ps)
+/*
+ * Lookup the task for the TID provided from user space and attach to
+ * it after doing proper sanity checks.
+ */
+static int attach_to_pi_owner(u32 uval, union futex_key *key,
+ struct futex_pi_state **ps)
{
- struct futex_q *match = futex_top_waiter(hb, key);
- struct futex_pi_state *pi_state = NULL;
- struct task_struct *p;
pid_t pid = uval & FUTEX_TID_MASK;
-
- /*
-* 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);
+ struct futex_pi_state *pi_state;
+ struct task_struct *p;
/*
* We are the first waiter - try to look up the real owner and attach
@@ -922,7 +917,7 @@ lookup_pi_state(u32 uval, struct futex_h
pi_state = alloc_pi_state();
/*
-* Initialize the pi_mutex in locked state and make 'p'
+* Initialize the pi_mutex in locked state and make @p
* the owner of it:
*/
rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p);
@@ -942,6 +937,25 @@ lookup_pi_state(u32 uval, struct futex_h
return 0;
}
+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);
+
+ /*
+* 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);
+
+ /*
+* We are the first waiter - try to look up the owner based on
+* @uval and attach to it.
+*/
+ return attach_to_pi_owner(uval, key, ps);
+}
+
/**
* futex_lock_pi_atomic() - Atomic work required to acquire a pi aware futex
* @uaddr: the pi futex user address
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
