Re: [PATCH] userfaultfd: release page in error path to avoid BUG_ON

From: Peter Xu <peterx@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lokesh Gidra <lokeshgidra@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] userfaultfd: release page in error path to avoid BUG_ON
Date: Wed, 28 Apr 2021 17:24:30 -0400	[thread overview]
Message-ID: <20210428212430.GA6462@xz-x1> (raw)
In-Reply-To: <alpine.LSU.2.11.2104281338380.9009@eggly.anvils>

On Wed, Apr 28, 2021 at 02:03:05PM -0700, Hugh Dickins wrote:

[...]

> > > +			put_page(*pagep);
> > > +			*pagep = NULL;
> > > +		}
> > >  		goto out;
> > 
> > All "goto out" in this functions looks weird as it returns directly... so if
> > you're touching this after all, I suggest we do "return -ENOMEM" directly and
> > drop the "ret = -ENOMEM".
> 
> No strong feeling either way from me on that: whichever looks best
> to you.  But I suspect the "ret = -ENOMEM" cannot be dropped,
> because it's relied on further down too?

Ah sorry I just noticed Axel didn't really touch that line.. :) So yeah please
also feel free to keep it as is.

If to drop it, "ret = -ENOMEM" can go as well, I think.. since all later errors
should always reset variable "ret".

Thanks,

-- 
Peter Xu