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bh=TwGyF4PkvxDzlLA402hHK1eLtIEBIL4SI/0qxIqDczQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zfFnOoP5liF9W0eIaPQY3fWY/x2c3YWeGxGG9Z+XtwTt6PdxvwTaVSJPl/wX9oHFa TN2zANmUIncV7Rx4/qsCq0LcMp4Wfg+6vxHO5Wt5VS0mnQryEzrkXU+ZLmL5qTwZbk NlIZmoUl864XszmR/3+xPQzAT+mE9qlCDRlYe16A= Date: Tue, 28 Mar 2023 16:04:33 -0700 From: Andrew Morton To: Christoph Hellwig Cc: Matthew Wilcox , Hugh Dickins , linux-afs@lists.infradead.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, cluster-devel@redhat.com, linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nilfs@vger.kernel.org Subject: Re: return an ERR_PTR from __filemap_get_folio v2 Message-Id: <20230328160433.4f3dc32b480239bce9e2f9ef@linux-foundation.org> In-Reply-To: <20230121065755.1140136-1-hch@lst.de> References: <20230121065755.1140136-1-hch@lst.de> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 290A34000A X-Stat-Signature: t16mtqzqbc1on4heg7w95pphhc8uq36m X-Rspam-User: X-HE-Tag: 1680044675-705767 X-HE-Meta: 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 oVpu27lx jItBe4Z5PDwGhkGf4/JEgowbZT8zzzq26GsqsbuZfY5OLHHp3k9lvXcr/08Ys7a+rXBWyvrRR/iyW13++0rcO5OEv/A91K2M9Lc9n+HQU6Y1j6BXiGA7xKYQPU/T1FU1GrBixGWQE795u2B6exQeHBOcc+OGXxzjjjz2bB+UsOwbyZ4D+KToehMjbea3LYXAHN27USDNgecuoUxQGrYfKnuFXoyzuqDmWwFpcF2q/LM0VXavWchPMTe9mfivhCoSP06eXj0euhixWt+nt8K/OGcaS+7DUfs2PN+AbCb/uOARPaCCKMpFcnU/r7ULkVq3S2FeEMtmiDZDhzKo04IL71NNClfm6VRUhPRKHLoZiPDDIVFgsxhBh2b8Ecz68xIyYCQJXUt9ByXLLMwc= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, 21 Jan 2023 07:57:48 +0100 Christoph Hellwig wrote: > __filemap_get_folio and its wrappers can return NULL for three different > conditions, which in some cases requires the caller to reverse engineer > the decision making. This is fixed by returning an ERR_PTR instead of > NULL and thus transporting the reason for the failure. But to make > that work we first need to ensure that no xa_value special case is > returned and thus return the FGP_ENTRY flag. It turns out that flag > is barely used and can usually be deal with in a better way. > > Note that the shmem patches in here are non-trivial and need some > careful review and testing. How are we going with the review and testing. I assume that we're now OK on the runtime testing front, but do you feel that review has been adequate? Thanks.