@@ -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;
@@ -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);
@@ -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);
@@ -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 */
@@ -1271,6 +1271,7 @@ 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,
@@ -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;
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@linux-foundation.org> Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/ Signed-off-by: David Howells <dhowells@redhat.com> cc: Jakub Kicinski <kuba@kernel.org> cc: Jens Axboe <axboe@kernel.dk> cc: Christoph Hellwig <hch@lst.de> cc: Al Viro <viro@zeniv.linux.org.uk> cc: Matthew Wilcox <willy@infradead.org> cc: Jan Kara <jack@suse.cz> cc: Jeff Layton <jlayton@kernel.org> cc: David Hildenbrand <david@redhat.com> cc: Christian Brauner <brauner@kernel.org> cc: Chuck Lever <chuck.lever@oracle.com> cc: Boris Pismenny <borisp@nvidia.com> cc: John Fastabend <john.fastabend@gmail.com> cc: Eric Dumazet <edumazet@google.com> cc: "David S. Miller" <davem@davemloft.net> cc: Paolo Abeni <pabeni@redhat.com> cc: linux-fsdevel@vger.kernel.org cc: linux-block@vger.kernel.org cc: linux-mm@kvack.org cc: netdev@vger.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(-)