linux-kernel - Re: [PATCH] fs: Add an explicit might

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Message-ID: <20200527190948.GE23230@ZenIV.linux.org.uk>
Date:   Wed, 27 May 2020 20:09:48 +0100
From:   Al Viro <viro@...iv.linux.org.uk>
To:     KP Singh <kpsingh@...omium.org>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        bpf@...r.kernel.org, Brendan Jackman <jackmanb@...omium.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH] fs: Add an explicit might_sleep() to iput

On Wed, May 27, 2020 at 04:17:53PM +0200, KP Singh wrote:
> From: KP Singh <kpsingh@...gle.com>
> 
> It is currently mentioned in the comments to the function that iput
> might sleep when the inode is destroyed. Have it call might_sleep, as
> dput already does.
> 
> Adding an explicity might_sleep() would help in quickly realizing that
> iput is called from a place where sleeping is not allowed when
> CONFIG_DEBUG_ATOMIC_SLEEP is enabled as noticed in the dicussion:

You do realize that there are some cases where iput() *is* guaranteed
to be non-blocking, right?