From: "Sharma, Sanjeev" <Sanjeev_Sharma@mentor.com>
To: Julian Calaby <julian.calaby@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>,
"dsd@gentoo.org" <dsd@gentoo.org>,
"kune@deine-taler.de" <kune@deine-taler.de>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: [PATCH v2] zd1211rw: replace ZD_ASSERT with lockdep_assert_held()
Date: Tue, 30 Sep 2014 07:42:11 +0000 [thread overview]
Message-ID: <FDC088D3B5555644AE135ED28A7ABDE950E5F3DF@EU-MBX-04.mgc.mentorg.com> (raw)
In-Reply-To: <CAGRGNgWOkzbu7sUxOqpgK_rzw1Xzny4aVFYOO6Rqd09-CpfvJA@mail.gmail.com>
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-----Original Message-----
From: Julian Calaby [mailto:julian.calaby@gmail.com]
Sent: Monday, September 15, 2014 11:32 AM
To: Sharma, Sanjeev
Cc: Johannes Berg; dsd@gentoo.org; kune@deine-taler.de; linux-wireless@vger.kernel.org; linux-kernel@vger.kernel.org; netdev@vger.kernel.org
Subject: Re: [PATCH v2] zd1211rw: replace ZD_ASSERT with lockdep_assert_held()
Hi Sanjeev,
On Thu, Sep 11, 2014 at 8:36 PM, Sharma, Sanjeev <Sanjeev_Sharma@mentor.com> wrote:
> -----Original Message-----
> From: Johannes Berg [mailto:johannes@sipsolutions.net]
> Sent: Thursday, September 11, 2014 3:42 PM
> To: Sharma, Sanjeev
> Cc: dsd@gentoo.org; kune@deine-taler.de;
> linux-wireless@vger.kernel.org; linux-kernel@vger.kernel.org;
> netdev@vger.kernel.org
> Subject: Re: [PATCH v2] zd1211rw: replace ZD_ASSERT with
> lockdep_assert_held()
>
> On Thu, 2014-09-11 at 15:39 +0530, Sanjeev Sharma wrote:
>> on some architecture spin_is_locked() always return false in
>> uniprocessor configuration and therefore it would be advise to
>> replace with lockdep_assert_held().
>>
>> Signed-off-by: Sanjeev Sharma <Sanjeev_Sharma@mentor.com>
>> ---
>> Changes in v2:
>> - corrected the typo
>
>> Now it compiles, but you got the logic wrong.
>
>> +++ b/drivers/net/wireless/zd1211rw/zd_mac.c
>> @@ -235,7 +235,7 @@ void zd_mac_clear(struct zd_mac *mac) {
>> flush_workqueue(zd_workqueue);
>> zd_chip_clear(&mac->chip);
>> - ZD_ASSERT(!spin_is_locked(&mac->lock));
>> + lockdep_assert_held(&mac->lock);
>> ZD_MEMCLEAR(mac, sizeof(struct zd_mac)); }
>
>>Look closely at this again.
>
> I didn't understand where I put wrong logic ?
I find it helps to spell out what code is doing in words.
E.g. the line you're removing is:
ZD_ASSERT(!spin_is_locked(&mac->lock));
So, we'll assert when spin_is_locked(&mac->lock) is false, i.e. when
mac->lock is not spin locked.
This isn't the same as what you're replacing it with.
I feel logic is absolutely correct and if you expand it will looks like ..
+#define lockdep_assert_held(l) do { \
+ WARN_ON(debug_locks && !lockdep_is_held(l)); \
+ } while (0)
Please refer http://lkml.iu.edu/hypermail/linux/kernel/1203.2/00369.html and also see include/linux/lockdep.h for more detail.
Thanks
Sanjeev Sharma
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prev parent reply other threads:[~2014-09-30 7:42 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-12 7:05 [PATCH] zd1211rw: replace ZD_ASSERT with lockdep_assert_held() Sanjeev Sharma
2014-08-19 6:39 ` Sharma, Sanjeev
2014-08-22 11:31 ` Johannes Berg
2014-08-22 11:40 ` Sharma, Sanjeev
2014-09-11 4:02 ` Sharma, Sanjeev
2014-09-11 6:53 ` Johannes Berg
2014-09-11 10:09 ` [PATCH v2] " Sanjeev Sharma
2014-09-11 10:12 ` Johannes Berg
2014-09-11 10:36 ` Sharma, Sanjeev
2014-09-11 10:42 ` Johannes Berg
2014-09-15 6:02 ` Julian Calaby
2014-09-30 7:42 ` Sharma, Sanjeev [this message]
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