io_uring: support MSG_WAITALL for IORING_OP_SEND(MSG)

stable inclusion
from stable-v5.10.165
commit f901b4bfd03ed234f72f28e27d965569531dc505
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7T7G4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f901b4bfd03ed234f72f28e27d965569531dc505



--------------------------------

commit 4c3c0943 upstream.

Like commit 7ba89d2a for recv/recvmsg, support MSG_WAITALL for the
send side. If this flag is set and we do a short send, retry for a
stream of seqpacket socket.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>