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From: Andreas Dilger <adilger@clusterfs.com>
To: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>, Andrew Morton <akpm@osdl.org>,
	linux-fsdevel@vger.kernel.org,
	Michael Halcrow <mhalcrow@us.ibm.com>
Subject: Re: i_mutex locking in generic_file_splice_write()
Date: Mon, 16 Oct 2006 11:58:08 -0600	[thread overview]
Message-ID: <20061016175808.GH6221@schatzie.adilger.int> (raw)
In-Reply-To: <20061015201415.GB13426@ca-server1.us.oracle.com>

On Oct 15, 2006  13:14 -0700, Mark Fasheh wrote:
> +void inode_double_lock(struct inode *inode1, struct inode *inode2)
> +{
> +	if (!inode1 || !inode2) {
> +		if (inode1)
> +			mutex_lock(&inode1->i_mutex);
> +		else if (inode2)
> +			mutex_lock(&inode2->i_mutex);
> +		return;
> +	}
> +
> +	if (inode1 == inode2) {
> +		mutex_lock(&inode1->i_mutex);

Could be a tiny bit cleaner if you put the "inode1 == inode2" case above:

void inode_double_lock(struct inode *inode1, struct inode *inode2)
{
	if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
		if (inode1)
			mutex_lock(&inode1->i_mutex);
		else if (inode2)
			mutex_lock(&inode2->i_mutex);
		return;
	}

	if (inode1 < inode2) {
		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
	} else {
		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
	}
}

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.


  reply	other threads:[~2006-10-16 17:58 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-12 19:01 i_mutex locking in generic_file_splice_write() Mark Fasheh
2006-10-12 19:54 ` Andrew Morton
2006-10-13  0:17   ` Mark Fasheh
2006-10-13  7:45     ` Jens Axboe
2006-10-13  8:11       ` Andrew Morton
2006-10-13  8:18         ` Jens Axboe
2006-10-13 19:44           ` Mark Fasheh
2006-10-15 18:05             ` Jens Axboe
2006-10-15 19:56               ` Mark Fasheh
2006-10-15 20:08                 ` Jens Axboe
2006-10-15 20:14                   ` Mark Fasheh
2006-10-16 17:58                     ` Andreas Dilger [this message]
2006-10-16 22:24                       ` Mark Fasheh

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