From: Cong Wang <amwang@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Ben Woodard <bwoodard@llnl.gov>,
David Howells <dhowells@redhat.com>,
Brian Behlendorf <behlendorf1@llnl.gov>
Subject: Re: [Patch v5] rwsem: fix rwsem_is_locked() bugs
Date: Fri, 16 Oct 2009 09:28:41 +0800 [thread overview]
Message-ID: <4AD7CC49.1080802@redhat.com> (raw)
In-Reply-To: <20091015164602.ac75126f.akpm@linux-foundation.org>
Andrew Morton wrote:
> On Wed, 14 Oct 2009 05:52:22 -0400
> Amerigo Wang <amwang@redhat.com> wrote:
>
>> --- a/include/linux/rwsem-spinlock.h
>> +++ b/include/linux/rwsem-spinlock.h
>> @@ -68,11 +68,9 @@ extern int __down_write_trylock(struct rw_semaphore *sem);
>> extern void __up_read(struct rw_semaphore *sem);
>> extern void __up_write(struct rw_semaphore *sem);
>> extern void __downgrade_write(struct rw_semaphore *sem);
>> +extern int __rwsem_is_locked(struct rw_semaphore *sem);
>>
>> -static inline int rwsem_is_locked(struct rw_semaphore *sem)
>> -{
>> - return (sem->activity != 0);
>> -}
>> +#define rwsem_is_locked(sem) __rwsem_is_locked(sem)
>>
>> #endif /* __KERNEL__ */
>> #endif /* _LINUX_RWSEM_SPINLOCK_H */
>> diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
>> index 9df3ca5..7014306 100644
>> --- a/lib/rwsem-spinlock.c
>> +++ b/lib/rwsem-spinlock.c
>> @@ -17,6 +17,19 @@ struct rwsem_waiter {
>> #define RWSEM_WAITING_FOR_WRITE 0x00000002
>> };
>>
>> +int __rwsem_is_locked(struct rw_semaphore *sem)
>> +{
>> + int ret = 1;
>> + unsigned long flags;
>> +
>> + if (spin_trylock_irqsave(&sem->wait_lock, flags)) {
>> + ret = (sem->activity != 0);
>> + spin_unlock_irqrestore(&sem->wait_lock, flags);
>> + }
>> + return ret;
>> +}
>> +EXPORT_SYMBOL(__rwsem_is_locked);
>
> Why the macro tricks? Can we do
Yes, better.
Thanks for your patch!
>
> --- a/include/linux/rwsem-spinlock.h~rwsem-fix-rwsem_is_locked-bugs-fix
> +++ a/include/linux/rwsem-spinlock.h
> @@ -68,9 +68,7 @@ extern int __down_write_trylock(struct r
> extern void __up_read(struct rw_semaphore *sem);
> extern void __up_write(struct rw_semaphore *sem);
> extern void __downgrade_write(struct rw_semaphore *sem);
> -extern int __rwsem_is_locked(struct rw_semaphore *sem);
> -
> -#define rwsem_is_locked(sem) __rwsem_is_locked(sem)
> +extern int rwsem_is_locked(struct rw_semaphore *sem);
>
> #endif /* __KERNEL__ */
> #endif /* _LINUX_RWSEM_SPINLOCK_H */
> --- a/lib/rwsem-spinlock.c~rwsem-fix-rwsem_is_locked-bugs-fix
> +++ a/lib/rwsem-spinlock.c
> @@ -17,7 +17,7 @@ struct rwsem_waiter {
> #define RWSEM_WAITING_FOR_WRITE 0x00000002
> };
>
> -int __rwsem_is_locked(struct rw_semaphore *sem)
> +int rwsem_is_locked(struct rw_semaphore *sem)
> {
> int ret = 1;
> unsigned long flags;
> @@ -28,7 +28,7 @@ int __rwsem_is_locked(struct rw_semaphor
> }
> return ret;
> }
> -EXPORT_SYMBOL(__rwsem_is_locked);
> +EXPORT_SYMBOL(rwsem_is_locked);
>
> /*
> * initialise the semaphore
> _
>
prev parent reply other threads:[~2009-10-16 1:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-14 9:52 [Patch v5] rwsem: fix rwsem_is_locked() bugs Amerigo Wang
2009-10-15 23:46 ` Andrew Morton
2009-10-16 1:28 ` Cong Wang [this message]
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