From: Dave Chinner <david@fromorbit.com>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, jmorris@namei.org,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
eparis@redhat.com, viro@zeniv.linux.org.uk,
Mimi Zohar <zohar@us.ibm.com>
Subject: Re: [PATCH v1.1 2/5] IMA: define readcount functions
Date: Tue, 2 Nov 2010 11:45:45 +1100 [thread overview]
Message-ID: <20101102004545.GQ2715@dastard> (raw)
In-Reply-To: <1288640739-3246-3-git-send-email-zohar@linux.vnet.ibm.com>
On Mon, Nov 01, 2010 at 03:45:36PM -0400, Mimi Zohar wrote:
> Define iget/iput_readcount() functions to be called from the VFS layer.
Can't say I like the function names. i_readcount_{inc,dec} seem more
appropriate, especially so they don't get confused with inode
reference counting...
Cheers,
Dave.
> +void iput_readcount(struct inode *inode)
> +{
> + spin_lock(&inode->i_lock);
> + if (unlikely((atomic_read(&inode->i_readcount) == 0)))
> + printk(KERN_INFO "i_readcount: imbalance ino %ld\n",
> + inode->i_ino);
> + else
> + atomic_dec(&inode->i_readcount);
> + spin_unlock(&inode->i_lock);
> +}
No need for the lock just to indicate an imbalance. You could just
use:
if (atomic_dec_return(&inode->i_readcount) < 0) {
.....
}
Given this is an integrity subsystem, I suspect the correct thing to
do here is BUG(), not just issue an informational message that
something is wrong with the integrity tracking....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2010-11-02 0:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-01 19:45 [PATCH v1.1 0/5] IMA: making i_readcount a first class inode citizen Mimi Zohar
2010-11-01 19:45 ` [PATCH v1.1 1/5] IMA: convert i_readcount to atomic Mimi Zohar
2010-11-01 19:45 ` [PATCH v1.1 2/5] IMA: define readcount functions Mimi Zohar
2010-11-02 0:45 ` Dave Chinner [this message]
2010-11-02 12:22 ` Mimi Zohar
2010-11-01 19:45 ` [PATCH v1.1 3/5] IMA: maintain i_readcount in the VFS layer Mimi Zohar
2010-11-01 19:45 ` [PATCH v1.1 4/5] IMA: remove IMA imbalance checking Mimi Zohar
2010-11-01 19:45 ` [PATCH v1.1 5/5] IMA: making i_readcount a first class inode citizen Mimi Zohar
2010-11-02 1:22 ` [PATCH v1.1 0/5] " Eric Paris
2010-11-02 2:12 ` Mimi Zohar
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