Stefan Metzmacher 44c816c8b9 io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL
[ Upstream commit 0031275d119efe16711cd93519b595e6f9b4b330 ]

Without that it's not safe to use them in a linked combination with
others.

Now combinations like IORING_OP_SENDMSG followed by IORING_OP_SPLICE
should be possible.

We already handle short reads and writes for the following opcodes:

- IORING_OP_READV
- IORING_OP_READ_FIXED
- IORING_OP_READ
- IORING_OP_WRITEV
- IORING_OP_WRITE_FIXED
- IORING_OP_WRITE
- IORING_OP_SPLICE
- IORING_OP_TEE

Now we have it for these as well:

- IORING_OP_SENDMSG
- IORING_OP_SEND
- IORING_OP_RECVMSG
- IORING_OP_RECV

For IORING_OP_RECVMSG we also check for the MSG_TRUNC and MSG_CTRUNC
flags in order to call req_set_fail_links().

There might be applications arround depending on the behavior
that even short send[msg]()/recv[msg]() retuns continue an
IOSQE_IO_LINK chain.

It's very unlikely that such applications pass in MSG_WAITALL,
which is only defined in 'man 2 recvmsg', but not in 'man 2 sendmsg'.

It's expected that the low level sock_sendmsg() call just ignores
MSG_WAITALL, as MSG_ZEROCOPY is also ignored without explicitly set
SO_ZEROCOPY.

We also expect the caller to know about the implicit truncation to
MAX_RW_COUNT, which we don't detect.

cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-07 15:00:06 +02:00
..
2020-10-16 11:11:22 -07:00
2020-11-19 22:38:29 -05:00
2020-09-10 14:03:31 -07:00
\n
2020-10-15 15:03:10 -07:00
2020-08-04 21:02:38 -04:00
2020-09-22 23:45:57 -04:00
2020-07-31 08:16:01 +02:00
2020-10-23 11:33:41 -07:00
2021-01-27 11:55:29 +01:00
2020-10-23 11:33:41 -07:00
2020-07-31 08:16:00 +02:00
2020-10-24 12:40:18 -07:00
2020-09-26 22:55:05 -04:00
2020-08-27 16:06:47 -04:00
2020-07-31 08:16:01 +02:00