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authorEric Dumazet <eric.dumazet@gmail.com>2012-04-05 03:05:35 +0000
committerDavid S. Miller <davem@davemloft.net>2012-04-05 19:04:27 -0400
commit35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2 (patch)
tree6e57508d6633c47b8846cfdbaefc33e6e0128a47 /fs/splice.c
parent78d50217baf36093ab320f95bae0d6452daec85c (diff)
downloadlinux-35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2.tar.gz
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>
Diffstat (limited to 'fs/splice.c')
-rw-r--r--fs/splice.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/splice.c b/fs/splice.c
index 5f883de7ef3a..f8476841eb04 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 @@ 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);
 }