From: David Howells <dhowells@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Hillf Danton <hdanton@sina.com>,
Jan Kara <jack@suse.cz>,
linux-xfs@vger.kernel.org, David Hildenbrand <david@redhat.com>,
linux-erofs@lists.ozlabs.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Jeff Layton <jlayton@kernel.org>,
Christian Brauner <brauner@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
linux-kernel@vger.kernel.org, dhowells@redhat.com,
linux-mm@kvack.org, Al Viro <viro@zeniv.linux.org.uk>,
Jason Gunthorpe <jgg@nvidia.com>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
Logan Gunthorpe <logang@deltatee.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v20 05/32] splice: Make splice from a DAX file use direct_splice_read()
Date: Fri, 19 May 2023 09:48:47 +0100 [thread overview]
Message-ID: <1742243.1684486127@warthog.procyon.org.uk> (raw)
In-Reply-To: <ZGcu6GVxOgYfy8x9@infradead.org>
Christoph Hellwig <hch@infradead.org> wrote:
> On Fri, May 19, 2023 at 08:40:20AM +0100, David Howells wrote:
> > +#ifdef CONFIG_FS_DAX
> > + if (IS_DAX(in->f_mapping->host))
>
> No need for the ifdef. IS_DAX is compile-time false if CONFIG_FS_DAX
> is not set.
Ah - it's not that IS_DAX() is conditionalised, it's that S_DAX is. There's a
bunch of places that use CONFIG_FS_DAX blocks, but I guess that's because they
include calls to functions that are conditionalised out.
I wonder if the dax_iomap_rw() declaration in the header can have a non-DAX
fallback that returns an error and then we can get rid of some of the other
conditionalisation.
David
prev parent reply other threads:[~2023-05-19 8:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230519074047.1739879-1-dhowells@redhat.com>
2023-05-19 7:40 ` [PATCH v20 05/32] splice: Make splice from a DAX file use direct_splice_read() David Howells
2023-05-19 8:10 ` Christoph Hellwig
2023-05-19 8:48 ` David Howells [this message]
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