linux/net/9p
Chirantan Ekbote d28c756cae 9p/net: Fix zero-copy path in the 9p virtio transport
The zero-copy optimization when reading or writing large chunks of data
is quite useful.  However, the 9p messages created through the zero-copy
write path have an incorrect message size: it should be the size of the
header + size of the data being written but instead it's just the size
of the header.

This only works if the server ignores the size field of the message and
otherwise breaks the framing of the protocol. Fix this by re-writing the
message size field with the correct value.

Tested by running `dd if=/dev/zero of=out bs=4k count=1` inside a
virtio-9p mount.

Link: http://lkml.kernel.org/r/20180717003529.114368-1-chirantan@chromium.org
Signed-off-by: Chirantan Ekbote <chirantan@chromium.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Cc: Dylan Reid <dgreid@chromium.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
2018-08-13 09:34:59 +09:00
..
client.c 9p: Embed wait_queue_head into p9_req_t 2018-08-13 09:21:44 +09:00
error.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
Kconfig IB: Revert "remove redundant INFINIBAND kconfig dependencies" 2018-05-28 10:40:16 -06:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mod.c net/9p: correct the variable name in v9fs_get_trans_by_name() comment 2018-05-07 23:38:15 -04:00
protocol.c 9p/net/protocol.c: return -ENOMEM when kmalloc() failed 2018-08-13 09:21:44 +09:00
protocol.h net/9p: Convert net/9p protocol dumps to tracepoints 2011-10-24 11:13:12 -05:00
trans_common.c net/9p: correct some comment errors in 9p file system code 2018-05-10 08:21:53 -04:00
trans_common.h net/9p: remove (now-)unused helpers 2015-04-11 22:28:29 -04:00
trans_fd.c Merge branch 'work.aio-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-04 13:57:43 -07:00
trans_rdma.c net/9p: correct some comment errors in 9p file system code 2018-05-10 08:21:53 -04:00
trans_virtio.c 9p/net: Fix zero-copy path in the 9p virtio transport 2018-08-13 09:34:59 +09:00
trans_xen.c net/9p/trans_xen.c: don't inclide rwlock.h directly 2018-06-07 17:34:34 -07:00
util.c net/9p: convert to idr_alloc() 2013-02-27 19:10:20 -08:00