Re: [RFC PATCH v1 2/3] locking/lockdep: Unify the return values of check_wait_context()

From: Xiongwei Song
Date: Mon Jul 12 2021 - 04:39:23 EST


On Sun, Jul 11, 2021 at 11:19 PM Waiman Long <llong@xxxxxxxxxx> wrote:
>
> On 7/11/21 10:14 AM, Xiongwei Song wrote:
> > From: Xiongwei Song <sxwjean@xxxxxxxxx>
> >
> > Unity the return values of check_wait_context() as check_prev_add(),
> "Unify"?
Sorry. Will improve the description.

> > check_irq_usage(), etc. 1 means no bug, 0 means there is a bug.
> >
> > The return values of print_lock_invalid_wait_context() are unnecessary,
> > remove them.
> >
> > Signed-off-by: Xiongwei Song <sxwjean@xxxxxxxxx>
> > ---
> > kernel/locking/lockdep.c | 20 ++++++++++----------
> > 1 file changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> > index bf1c00c881e4..8b50da42f2c6 100644
> > --- a/kernel/locking/lockdep.c
> > +++ b/kernel/locking/lockdep.c
> > @@ -4635,16 +4635,16 @@ static inline short task_wait_context(struct task_struct *curr)
> > return LD_WAIT_MAX;
> > }
> >
> > -static int
> > +static void
> > print_lock_invalid_wait_context(struct task_struct *curr,
> > struct held_lock *hlock)
> > {
> > short curr_inner;
> >
> > if (!debug_locks_off())
> > - return 0;
> > + return;
> > if (debug_locks_silent)
> > - return 0;
> > + return;
> >
> > pr_warn("\n");
> > pr_warn("=============================\n");
> > @@ -4664,8 +4664,6 @@ print_lock_invalid_wait_context(struct task_struct *curr,
> >
> > pr_warn("stack backtrace:\n");
> > dump_stack();
> > -
> > - return 0;
> > }
> >
> > /*
> > @@ -4691,7 +4689,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
> > int depth;
> >
> > if (!next_inner || next->trylock)
> > - return 0;
> > + return 1;
> >
> > if (!next_outer)
> > next_outer = next_inner;
> > @@ -4723,10 +4721,12 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
> > }
> > }
> >
> > - if (next_outer > curr_inner)
> > - return print_lock_invalid_wait_context(curr, next);
> > + if (next_outer > curr_inner) {
> > + print_lock_invalid_wait_context(curr, next);
> > + return 0;
> > + }
> >
> > - return 0;
> > + return 1;
> > }
> >
> > #else /* CONFIG_PROVE_LOCKING */
> > @@ -4962,7 +4962,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
> > #endif
> > hlock->pin_count = pin_count;
> >
> > - if (check_wait_context(curr, hlock))
> > + if (!check_wait_context(curr, hlock))
> > return 0;
> >
> > /* Initialize the lock usage bit */
>
> There is also another check_wait_context() in the "#else
> CONFIG_PROVE_LOCKING" path that needs to be kept in sync.
Oops, my fault.

For clarity,
> maybe you should state the meaning of the return value in the comment
> above the function.
Good point. Thanks.

Regards,
Xiongwei
>
> Cheers,
> Longman
>
> check_wait_context
>