[PATCH 07/37] locking/lockdep: Prepare valid_state() to handle plain masks

Frederic Weisbecker
2019-02-28T17:16:15Z

mark_lock_irq() is going to deal with lock usages that gather multiple
softirq vectors at once. Therefore the validation through valid_state()
will need to handle expanded usage masks.

So enhance valid_state() to that purpose.

Reviewed-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
kernel/locking/lockdep.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ac1efd16f3e7..2321b5e16cdf 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -487,7 +487,21 @@ static inline u64 lock_flag(enum lock_usage_bit bit)

static u64 lock_usage_mask(struct lock_usage *usage)
{
- return lock_flag(usage->bit);
+ u64 vectors = usage->vector;
+ u64 mask = 0ULL;
+ int nr;
+
+ if (!vectors)
+ return lock_flag(usage->bit);
+
+ /* Only softirqs can have non-zero vectors */
+ WARN_ON_ONCE(usage->bit < LOCK_USED_IN_SOFTIRQ ||
+ usage->bit > LOCK_ENABLED_SOFTIRQ_READ);
+
+ for_each_bit_nr(vectors, nr)
+ mask |= lock_flag(usage->bit) << (4 * nr);
+
+ return mask;
}

static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
@@ -2558,10 +2572,23 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this,
*/
static inline int
valid_state(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+ u64 new_mask, u64 bad_mask)
{
- if (unlikely(hlock_class(this)->usage_mask & lock_flag(bad_bit)))
+ u64 bad_intersec;
+
+ bad_intersec = hlock_class(this)->usage_mask & bad_mask;
+
+ if (unlikely(bad_intersec)) {
+ enum lock_usage_bit new_bit, bad_bit;
+ int err;
+
+ err = find_exclusive_match(new_mask,
+ bad_intersec, &new_bit, &bad_bit);
+ if (WARN_ON_ONCE(err < 0))
+ return err;
+
return print_usage_bug(curr, this, bad_bit, new_bit);
+ }
return 1;
}

@@ -2753,7 +2780,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
* Validate that this particular lock does not have conflicting
* usage states.
*/
- if (!valid_state(curr, this, new_usage->bit, excl_usage.bit))
+ if (!valid_state(curr, this, lock_usage_mask(new_usage),
+ lock_usage_mask(&excl_usage)))
return 0;

/*
@@ -2769,7 +2797,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
*/
if (!read) {
excl_usage.bit += LOCK_USAGE_READ_MASK;
- if (!valid_state(curr, this, new_usage->bit, excl_usage.bit))
+ if (!valid_state(curr, this, lock_usage_mask(new_usage),
+ lock_usage_mask(&excl_usage)))
return 0;

if (STRICT_READ_CHECKS &&
--
2.21.0