From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: "Raphael S. Carvalho" <raphaelsc@scylladb.com>,
linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
djwong@kernel.org, Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH v2] mm: Fix error handling in __filemap_get_folio() with FGP_NOWAIT
Date: Mon, 24 Feb 2025 15:33:29 +0000 [thread overview]
Message-ID: <Z7yRSe-nkfMz4TS2@casper.infradead.org> (raw)
In-Reply-To: <20250224141744.GA1088@lst.de>
On Mon, Feb 24, 2025 at 03:17:44PM +0100, Christoph Hellwig wrote:
> On Mon, Feb 24, 2025 at 05:13:28AM -0300, Raphael S. Carvalho wrote:
> > + if (err) {
> > + /* Prevents -ENOMEM from escaping to user space with FGP_NOWAIT */
> > + if ((fgp_flags & FGP_NOWAIT) && err == -ENOMEM)
> > + err = -EAGAIN;
> > return ERR_PTR(err);
>
> I don't think the comment is all that useful. It's also overly long.
>
> I'd suggest this instead:
>
> /*
> * When NOWAIT I/O fails to allocate folios this could
> * be due to a nonblocking memory allocation and not
> * because the system actually is out of memory.
> * Return -EAGAIN so that there caller retries in a
> * blocking fashion instead of propagating -ENOMEM
> * to the application.
> */
I don't think it needs a comment at all, but the memory allocation
might be for something other than folios, so your suggested comment
is misleading.
next prev parent reply other threads:[~2025-02-24 15:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-24 8:13 Raphael S. Carvalho
2025-02-24 14:17 ` Christoph Hellwig
2025-02-24 15:33 ` Matthew Wilcox [this message]
2025-02-24 15:45 ` Raphael S. Carvalho
2025-02-24 15:49 ` Matthew Wilcox
2025-02-24 15:50 ` Raphael S. Carvalho
2025-02-24 15:51 ` Matthew Wilcox
2025-02-24 15:52 ` Raphael S. Carvalho
2025-02-24 15:56 ` Christoph Hellwig
2025-02-24 16:02 ` Christoph Hellwig
2025-02-24 16:15 ` Raphael S. Carvalho
2025-02-25 16:04 ` Raphael S. Carvalho
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