tcp: tcp_sendpages() should call tcp_push() once
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 <therbert@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: H.K. Jerry Chu <hkchu@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail>com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 <linux/uio.h>
#include <linux/security.h>
#include <linux/gfp.h>
+#include <linux/socket.h>
/*
* Attempt to steal a page from a pipe buffer. This should perhaps go into
@@ -690,7 +691,9 @@
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 @@
#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 @@
}
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 @@
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);
}