All of lore.kernel.org
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>,
	mingo@redhat.com, will@kernel.org, kvalo@codeaurora.org,
	davem@davemloft.net, kuba@kernel.org, ath10k@lists.infradead.org,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] lockdep: add lockdep_assert_not_held()
Date: Mon, 15 Feb 2021 17:04:10 +0100	[thread overview]
Message-ID: <YCqbehyyeUoL0pPT@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <79aeb83a288051bd3a2a3f15e5ac42e06f154d48.camel@sipsolutions.net>

On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote:
> On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote:
> > 
> > I think something like so will work, but please double check.
> 
> Yeah, that looks better.
> 
> > +++ b/include/linux/lockdep.h
> > @@ -294,11 +294,15 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
> >  
> >  #define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
> >  
> > -#define lockdep_assert_held(l)	do {				\
> > -		WARN_ON(debug_locks && !lockdep_is_held(l));	\
> > +#define lockdep_assert_held(l)	do {					\
> > +		WARN_ON(debug_locks && lockdep_is_held(l) == 0));	\
> >  	} while (0)
> 
> That doesn't really need to change? It's the same.

Correct, but I found it more symmetric vs the not implementation below.

> > -#define lockdep_assert_held_write(l)	do {			\
> > +#define lockdep_assert_not_held(l)	do {				\
> > +		WARN_ON(debug_locks && lockdep_is_held(l) == 1));	\
> > +	} while (0)
> > +
> > +#define lockdep_assert_held_write(l)	do {				\
> >  		WARN_ON(debug_locks && !lockdep_is_held_type(l, 0));	\
> >  	} while (0)
> >  
> > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> > index c1418b47f625..983ba206f7b2 100644
> > --- a/kernel/locking/lockdep.
> > +++ b/kernel/locking/lockdep.c
> > @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
> >  	int ret = 0;
> >  
> >  	if (unlikely(!lockdep_enabled()))
> > -		return 1; /* avoid false negative lockdep_assert_held() */
> > +		return -1; /* avoid false negative lockdep_assert_held() */
> 
> Maybe add lockdep_assert_not_held() to the comment, to explain the -1
> (vs non-zero)?

Yeah, or frob a '*' in there.

WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org, ath10k@lists.infradead.org,
	mingo@redhat.com, Shuah Khan <skhan@linuxfoundation.org>,
	kuba@kernel.org, will@kernel.org, davem@davemloft.net,
	kvalo@codeaurora.org
Subject: Re: [PATCH 1/2] lockdep: add lockdep_assert_not_held()
Date: Mon, 15 Feb 2021 17:04:10 +0100	[thread overview]
Message-ID: <YCqbehyyeUoL0pPT@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <79aeb83a288051bd3a2a3f15e5ac42e06f154d48.camel@sipsolutions.net>

On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote:
> On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote:
> > 
> > I think something like so will work, but please double check.
> 
> Yeah, that looks better.
> 
> > +++ b/include/linux/lockdep.h
> > @@ -294,11 +294,15 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
> >  
> >  #define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
> >  
> > -#define lockdep_assert_held(l)	do {				\
> > -		WARN_ON(debug_locks && !lockdep_is_held(l));	\
> > +#define lockdep_assert_held(l)	do {					\
> > +		WARN_ON(debug_locks && lockdep_is_held(l) == 0));	\
> >  	} while (0)
> 
> That doesn't really need to change? It's the same.

Correct, but I found it more symmetric vs the not implementation below.

> > -#define lockdep_assert_held_write(l)	do {			\
> > +#define lockdep_assert_not_held(l)	do {				\
> > +		WARN_ON(debug_locks && lockdep_is_held(l) == 1));	\
> > +	} while (0)
> > +
> > +#define lockdep_assert_held_write(l)	do {				\
> >  		WARN_ON(debug_locks && !lockdep_is_held_type(l, 0));	\
> >  	} while (0)
> >  
> > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> > index c1418b47f625..983ba206f7b2 100644
> > --- a/kernel/locking/lockdep.
> > +++ b/kernel/locking/lockdep.c
> > @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
> >  	int ret = 0;
> >  
> >  	if (unlikely(!lockdep_enabled()))
> > -		return 1; /* avoid false negative lockdep_assert_held() */
> > +		return -1; /* avoid false negative lockdep_assert_held() */
> 
> Maybe add lockdep_assert_not_held() to the comment, to explain the -1
> (vs non-zero)?

Yeah, or frob a '*' in there.

_______________________________________________
ath10k mailing list
ath10k@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/ath10k

  reply	other threads:[~2021-02-15 16:12 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-12 23:28 [PATCH 0/2] Add lockdep_assert_not_held() Shuah Khan
2021-02-12 23:28 ` Shuah Khan
2021-02-12 23:28 ` [PATCH 1/2] lockdep: add lockdep_assert_not_held() Shuah Khan
2021-02-12 23:28   ` Shuah Khan
2021-02-14 17:53   ` Peter Zijlstra
2021-02-14 17:53     ` Peter Zijlstra
2021-02-15 10:44     ` Peter Zijlstra
2021-02-15 10:44       ` Peter Zijlstra
2021-02-15 13:12       ` Johannes Berg
2021-02-15 13:12         ` Johannes Berg
2021-02-15 16:04         ` Peter Zijlstra [this message]
2021-02-15 16:04           ` Peter Zijlstra
2021-02-15 16:10           ` Johannes Berg
2021-02-15 16:10             ` Johannes Berg
2021-02-22 20:51             ` Shuah Khan
2021-02-22 20:51               ` Shuah Khan
2021-02-12 23:28 ` [PATCH 2/2] ath10k: detect conf_mutex held ath10k_drain_tx() calls Shuah Khan
2021-02-12 23:28   ` Shuah Khan
2021-02-14  6:08   ` Kalle Valo
2021-02-14  6:08     ` Kalle Valo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YCqbehyyeUoL0pPT@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=ath10k@lists.infradead.org \
    --cc=davem@davemloft.net \
    --cc=johannes@sipsolutions.net \
    --cc=kuba@kernel.org \
    --cc=kvalo@codeaurora.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=skhan@linuxfoundation.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.