[PATCH 05/32] locking/lockdep: Prepare valid_state() to handle plain masks

Frederic Weisbecker
2019-02-12T17:14:50Z

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.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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 | 44 +++++++++++++++++++++++++++++++++++-----
1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 578dd57f70d3..6b625b70598a 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2538,7 +2538,26 @@ print_usage_bug(struct task_struct *curr, struct held_lock *this,

static u64 lock_usage_mask(struct lock_usage *usage)
{
- return BIT(usage->bit);
+ int nr = 0;
+ u64 vectors = usage->vector;
+ u64 mask = 0ULL;
+
+ 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);
+
+ while (vectors) {
+ long fs = __ffs64(vectors) + 1;
+
+ vectors >>= fs;
+ nr += fs;
+ mask |= lock_flag(usage->bit) << (4 * (nr - 1));
+ }
+
+ return mask;
}

/*
@@ -2546,10 +2565,23 @@ static u64 lock_usage_mask(struct lock_usage *usage)
*/
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;
}

@@ -2746,7 +2778,8 @@ 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;

/*
@@ -2762,7 +2795,8 @@ 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 &&
--
2.17.1