* [PATCH v20 05/32] splice: Make splice from a DAX file use direct_splice_read() [not found] <20230519074047.1739879-1-dhowells@redhat.com> @ 2023-05-19 7:40 ` David Howells 2023-05-19 8:10 ` Christoph Hellwig 2023-05-19 8:48 ` David Howells 0 siblings, 2 replies; 3+ messages in thread From: David Howells @ 2023-05-19 7:40 UTC (permalink / raw) To: Jens Axboe, Al Viro, Christoph Hellwig Cc: linux-erofs, linux-block, Hillf Danton, Jan Kara, linux-xfs, David Hildenbrand, Linus Torvalds, Jeff Layton, Christian Brauner, Matthew Wilcox, linux-kernel, David Howells, linux-mm, Jason Gunthorpe, linux-fsdevel, linux-ext4, Logan Gunthorpe, Christoph Hellwig Make a read splice from a DAX file go directly to direct_splice_read() to do the reading as filemap_splice_read() is unlikely to find any pagecache to splice. I think this affects only erofs, Ext2, Ext4, fuse and XFS. Signed-off-by: David Howells <dhowells@redhat.com> cc: Christoph Hellwig <hch@lst.de> cc: Al Viro <viro@zeniv.linux.org.uk> cc: Jens Axboe <axboe@kernel.dk> cc: linux-erofs@lists.ozlabs.org cc: linux-ext4@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-xfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-mm@kvack.org --- fs/splice.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/splice.c b/fs/splice.c index 1e0b7c7038b5..7b818b5b18d4 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -421,6 +421,11 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, struct kiocb kiocb; int ret; +#ifdef CONFIG_FS_DAX + if (IS_DAX(in->f_mapping->host)) + return direct_splice_read(in, ppos, pipe, len, flags); +#endif + iov_iter_pipe(&to, ITER_DEST, pipe, len); init_sync_kiocb(&kiocb, in); kiocb.ki_pos = *ppos; ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v20 05/32] splice: Make splice from a DAX file use direct_splice_read() 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 1 sibling, 0 replies; 3+ messages in thread From: Christoph Hellwig @ 2023-05-19 8:10 UTC (permalink / raw) To: David Howells Cc: Jens Axboe, linux-block, Hillf Danton, Jan Kara, linux-xfs, David Hildenbrand, linux-erofs, Linus Torvalds, Jeff Layton, Christian Brauner, Matthew Wilcox, linux-kernel, Christoph Hellwig, linux-mm, Al Viro, Jason Gunthorpe, linux-fsdevel, linux-ext4, Logan Gunthorpe, Christoph Hellwig 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. A comment on why we're doing this in the code would probably be useful as well. ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v20 05/32] splice: Make splice from a DAX file use direct_splice_read() 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 1 sibling, 0 replies; 3+ messages in thread From: David Howells @ 2023-05-19 8:48 UTC (permalink / raw) To: Christoph Hellwig Cc: Jens Axboe, linux-block, Hillf Danton, Jan Kara, linux-xfs, David Hildenbrand, linux-erofs, Linus Torvalds, Jeff Layton, Christian Brauner, Matthew Wilcox, linux-kernel, dhowells, linux-mm, Al Viro, Jason Gunthorpe, linux-fsdevel, linux-ext4, Logan Gunthorpe, Christoph Hellwig 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 ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-05-19 8:49 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [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
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