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From:   David Howells <dhowells@redhat.com>
To:     Jens Axboe <axboe@kernel.dk>, Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>
Cc:     David Howells <dhowells@redhat.com>,
        Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Logan Gunthorpe <logang@deltatee.com>,
        Hillf Danton <hdanton@sina.com>,
        Christian Brauner <brauner@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Christoph Hellwig <hch@lst.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-trace-kernel@vger.kernel.org
Subject: [PATCH v22 26/31] trace: Convert trace/seq to use copy_splice_read()
Date:   Mon, 22 May 2023 14:50:13 +0100
Message-Id: <20230522135018.2742245-27-dhowells@redhat.com>
In-Reply-To: <20230522135018.2742245-1-dhowells@redhat.com>
References: <20230522135018.2742245-1-dhowells@redhat.com>
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For the splice from the trace seq buffer, just use copy_splice_read().

In the future, something better can probably be done by gifting pages from
seq->buf into the pipe, but that would require changing seq->buf into a
vmap over an array of pages.

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: Steven Rostedt <rostedt@goodmis.org>
cc: Masami Hiramatsu <mhiramat@kernel.org>
cc: linux-kernel@vger.kernel.org
cc: linux-trace-kernel@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ebc59781456a..c210d02fac97 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5171,7 +5171,7 @@ static const struct file_operations tracing_fops = {
 	.open		= tracing_open,
 	.read		= seq_read,
 	.read_iter	= seq_read_iter,
-	.splice_read	= generic_file_splice_read,
+	.splice_read	= copy_splice_read,
 	.write		= tracing_write_stub,
 	.llseek		= tracing_lseek,
 	.release	= tracing_release,