From: Dan Carpenter <dan.carpenter@oracle.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-mm@kvack.org
Subject: Re: mm: keep page cache radix tree nodes in check
Date: Thu, 10 Mar 2016 22:35:22 +0300 [thread overview]
Message-ID: <20160310193522.GC5273@mwanda> (raw)
In-Reply-To: <20160310161200.GA11651@cmpxchg.org>
On Thu, Mar 10, 2016 at 11:12:00AM -0500, Johannes Weiner wrote:
> We know that page->tree[page->index] is present and the tree is
> locked, so __radix_tree_lookup() will always return with an entry, as
> well as &node and &slot set. I'm not sure how you would annotate this.
>
That's tricky...
> Is it also warning about slot?
It does, yes.
> Or can it know that they are always set
> together?
It knows they are set together but it warns about both.
> Could it maybe be linked to the function's return value? I
> would prefer not setting node and slot to NULL to suppress the false
> positive. However, what we could do is add a BUG_ON() if the function
> call returns NULL. Would that be enough of a hint to the checker that
> we expect the function to be always successful and set node and slot?
I'm sort of just trying to get a feel for what the issues are. Calling
BUG_ON() would silence the warning, yes.
regards,
dan carpenter
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prev parent reply other threads:[~2016-03-10 19:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 12:59 mm: keep page cache radix tree nodes in check Dan Carpenter
2016-03-10 16:12 ` Johannes Weiner
2016-03-10 19:35 ` Dan Carpenter [this message]
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