From 35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 5 Apr 2012 03:05:35 +0000 Subject: [PATCH] tcp: tcp_sendpages() should call tcp_push() once MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 2f533844242 (tcp: allow splice() to build full TSO packets) added a regression for splice() calls using SPLICE_F_MORE. We need to call tcp_flush() at the end of the last page processed in tcp_sendpages(), or else transmits can be deferred and future sends stall. Add a new internal flag, MSG_SENDPAGE_NOTLAST, acting like MSG_MORE, but with different semantic. For all sendpage() providers, its a transparent change. Only sock_sendpage() and tcp_sendpages() can differentiate the two different flags provided by pipe_to_sendpage() Reported-by: Tom Herbert Cc: Nandita Dukkipati Cc: Neal Cardwell Cc: Tom Herbert Cc: Yuchung Cheng Cc: H.K. Jerry Chu Cc: Maciej Żenczykowski Cc: Mahesh Bandewar Cc: Ilpo Järvinen Signed-off-by: Eric Dumazet com> Signed-off-by: David S. Miller --- fs/splice.c | 5 ++++- include/linux/socket.h | 2 +- net/ipv4/tcp.c | 2 +- net/socket.c | 6 +++--- 4 files changed, 9 insertions(+), 6 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 5f883de..f847684 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -30,6 +30,7 @@ #include #include #include +#include /* * Attempt to steal a page from a pipe buffer. This should perhaps go into @@ -690,7 +691,9 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe, if (!likely(file->f_op && file->f_op->sendpage)) return -EINVAL; - more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; + more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0; + if (sd->len < sd->total_len) + more |= MSG_SENDPAGE_NOTLAST; return file->f_op->sendpage(file, buf->page, buf->offset, sd->len, &pos, more); } diff --git a/include/linux/socket.h b/include/linux/socket.h index da2d3e2..b84bbd4 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -265,7 +265,7 @@ struct ucred { #define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */ #define MSG_MORE 0x8000 /* Sender will send more */ #define MSG_WAITFORONE 0x10000 /* recvmmsg(): block until 1+ packets avail */ - +#define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */ #define MSG_EOF MSG_FIN #define MSG_CMSG_CLOEXEC 0x40000000 /* Set close_on_exit for file diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2ff6f45..5d54ed3 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -860,7 +860,7 @@ wait_for_memory: } out: - if (copied && !(flags & MSG_MORE)) + if (copied && !(flags & MSG_SENDPAGE_NOTLAST)) tcp_push(sk, flags, mss_now, tp->nonagle); return copied; diff --git a/net/socket.c b/net/socket.c index 484cc69..851edcd 100644 --- a/net/socket.c +++ b/net/socket.c @@ -811,9 +811,9 @@ static ssize_t sock_sendpage(struct file *file, struct page *page, sock = file->private_data; - flags = !(file->f_flags & O_NONBLOCK) ? 0 : MSG_DONTWAIT; - if (more) - flags |= MSG_MORE; + flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0; + /* more is a combination of MSG_MORE and MSG_SENDPAGE_NOTLAST */ + flags |= more; return kernel_sendpage(sock, page, offset, size, flags); } -- 1.7.10.4