From: Andrew Morton <akpm@linux-foundation.org>
To: Amerigo Wang <amwang@redhat.com>
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: Thu, 15 Oct 2009 16:46:02 -0700 [thread overview]
Message-ID: <20091015164602.ac75126f.akpm@linux-foundation.org> (raw)
In-Reply-To: <20091014095503.4235.63028.sendpatchset@localhost.localdomain>
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
--- 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
_
next prev parent reply other threads:[~2009-10-15 23:46 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 [this message]
2009-10-16 1:28 ` Cong Wang
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