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Message-ID: <20230605124600.1722160-5-dhowells@redhat.com>
Date: Mon, 5 Jun 2023 13:45:53 +0100
From: David Howells <dhowells@...hat.com>
To: netdev@...r.kernel.org,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: David Howells <dhowells@...hat.com>,
Chuck Lever <chuck.lever@...cle.com>,
Boris Pismenny <borisp@...dia.com>,
John Fastabend <john.fastabend@...il.com>,
Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>,
David Ahern <dsahern@...nel.org>,
Matthew Wilcox <willy@...radead.org>,
Jens Axboe <axboe@...nel.dk>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, Christoph Hellwig <hch@....de>,
Al Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
Jeff Layton <jlayton@...nel.org>,
David Hildenbrand <david@...hat.com>,
Christian Brauner <brauner@...nel.org>,
linux-fsdevel@...r.kernel.org, linux-block@...r.kernel.org
Subject: [PATCH net-next v4 04/11] splice, net: Add a splice_eof op to file-ops and socket-ops
Add an optional method, ->splice_eof(), to allow splice to indicate the
premature termination of a splice to struct file_operations and struct
proto_ops.
This is called if sendfile() or splice() encounters all of the following
conditions inside splice_direct_to_actor():
(1) the user did not set SPLICE_F_MORE (splice only), and
(2) an EOF condition occurred (->splice_read() returned 0), and
(3) we haven't read enough to fulfill the request (ie. len > 0 still), and
(4) we have already spliced at least one byte.
A further patch will modify the behaviour of SPLICE_F_MORE to always be
passed to the actor if either the user set it or we haven't yet read
sufficient data to fulfill the request.
Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Jakub Kicinski <kuba@...nel.org>
cc: Jens Axboe <axboe@...nel.dk>
cc: Christoph Hellwig <hch@....de>
cc: Al Viro <viro@...iv.linux.org.uk>
cc: Matthew Wilcox <willy@...radead.org>
cc: Jan Kara <jack@...e.cz>
cc: Jeff Layton <jlayton@...nel.org>
cc: David Hildenbrand <david@...hat.com>
cc: Christian Brauner <brauner@...nel.org>
cc: Chuck Lever <chuck.lever@...cle.com>
cc: Boris Pismenny <borisp@...dia.com>
cc: John Fastabend <john.fastabend@...il.com>
cc: Eric Dumazet <edumazet@...gle.com>
cc: "David S. Miller" <davem@...emloft.net>
cc: Paolo Abeni <pabeni@...hat.com>
cc: linux-fsdevel@...r.kernel.org
cc: linux-block@...r.kernel.org
cc: linux-mm@...ck.org
cc: netdev@...r.kernel.org
---
fs/splice.c | 31 ++++++++++++++++++++++++++++++-
include/linux/fs.h | 1 +
include/linux/net.h | 1 +
include/linux/splice.h | 1 +
include/net/sock.h | 1 +
net/socket.c | 10 ++++++++++
6 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/fs/splice.c b/fs/splice.c
index 9b1d43c0c562..3063f9a3ba62 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -969,6 +969,17 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
return out->f_op->splice_write(pipe, out, ppos, len, flags);
}
+/*
+ * Indicate to the caller that there was a premature EOF when reading from the
+ * source and the caller didn't indicate they would be sending more data after
+ * this.
+ */
+static void do_splice_eof(struct splice_desc *sd)
+{
+ if (sd->splice_eof)
+ sd->splice_eof(sd);
+}
+
/*
* Attempt to initiate a splice from a file to a pipe.
*/
@@ -1068,7 +1079,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
ret = do_splice_to(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
- goto out_release;
+ goto read_failure;
read_len = ret;
sd->total_len = read_len;
@@ -1108,6 +1119,15 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
file_accessed(in);
return bytes;
+read_failure:
+ /*
+ * If the user did *not* set SPLICE_F_MORE *and* we didn't hit that
+ * "use all of len" case that cleared SPLICE_F_MORE, *and* we did a
+ * "->splice_in()" that returned EOF (ie zero) *and* we have sent at
+ * least 1 byte *then* we will also do the ->splice_eof() call.
+ */
+ if (ret == 0 && !more && len > 0 && bytes)
+ do_splice_eof(sd);
out_release:
/*
* If we did an incomplete transfer we must release
@@ -1136,6 +1156,14 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
sd->flags);
}
+static void direct_file_splice_eof(struct splice_desc *sd)
+{
+ struct file *file = sd->u.file;
+
+ if (file->f_op->splice_eof)
+ file->f_op->splice_eof(file);
+}
+
/**
* do_splice_direct - splices data directly between two files
* @in: file to splice from
@@ -1161,6 +1189,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
.flags = flags,
.pos = *ppos,
.u.file = out,
+ .splice_eof = direct_file_splice_eof,
.opos = opos,
};
long ret;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f8254c3acf83..e393f2550300 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1796,6 +1796,7 @@ struct file_operations {
int (*flock) (struct file *, int, struct file_lock *);
ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
+ void (*splice_eof)(struct file *file);
int (*setlease)(struct file *, long, struct file_lock **, void **);
long (*fallocate)(struct file *file, int mode, loff_t offset,
loff_t len);
diff --git a/include/linux/net.h b/include/linux/net.h
index b73ad8e3c212..8defc8f1d82e 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -210,6 +210,7 @@ struct proto_ops {
int offset, size_t size, int flags);
ssize_t (*splice_read)(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
+ void (*splice_eof)(struct socket *sock);
int (*set_peek_off)(struct sock *sk, int val);
int (*peek_len)(struct socket *sock);
diff --git a/include/linux/splice.h b/include/linux/splice.h
index 991ae318b6eb..4fab18a6e371 100644
--- a/include/linux/splice.h
+++ b/include/linux/splice.h
@@ -38,6 +38,7 @@ struct splice_desc {
struct file *file; /* file to read/write */
void *data; /* cookie */
} u;
+ void (*splice_eof)(struct splice_desc *sd); /* Unexpected EOF handler */
loff_t pos; /* file position */
loff_t *opos; /* sendfile: output position */
size_t num_spliced; /* number of bytes already spliced */
diff --git a/include/net/sock.h b/include/net/sock.h
index 656ea89f60ff..330b9c24ef70 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1267,6 +1267,7 @@ struct proto {
size_t len, int flags, int *addr_len);
int (*sendpage)(struct sock *sk, struct page *page,
int offset, size_t size, int flags);
+ void (*splice_eof)(struct socket *sock);
int (*bind)(struct sock *sk,
struct sockaddr *addr, int addr_len);
int (*bind_add)(struct sock *sk,
diff --git a/net/socket.c b/net/socket.c
index c4d9104418c8..b778fc03c6e0 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -130,6 +130,7 @@ static int sock_fasync(int fd, struct file *filp, int on);
static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags);
+static void sock_splice_eof(struct file *file);
#ifdef CONFIG_PROC_FS
static void sock_show_fdinfo(struct seq_file *m, struct file *f)
@@ -163,6 +164,7 @@ static const struct file_operations socket_file_ops = {
.fasync = sock_fasync,
.splice_write = splice_to_socket,
.splice_read = sock_splice_read,
+ .splice_eof = sock_splice_eof,
.show_fdinfo = sock_show_fdinfo,
};
@@ -1076,6 +1078,14 @@ static ssize_t sock_splice_read(struct file *file, loff_t *ppos,
return sock->ops->splice_read(sock, ppos, pipe, len, flags);
}
+static void sock_splice_eof(struct file *file)
+{
+ struct socket *sock = file->private_data;
+
+ if (sock->ops->splice_eof)
+ sock->ops->splice_eof(sock);
+}
+
static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
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