We currently don't attempt to get the full asked for length even if MSG_WAITALL is set, if we get a partial receive. If we do see a partial receive, then just note how many bytes we did and return -EAGAIN to get it retried.

The iov is advanced appropriately for the vector based case, and we manually bump the buffer and remainder for the non-vector case.

Cc: stable@vger.kernel.org Reported-by: Constantine Gavrilov constantine.gavrilov@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk --- fs/io_uring.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c index f41d91ce1fd0..a70de170aea1 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -612,6 +612,7 @@ struct io_sr_msg { int msg_flags; int bgid; size_t len; + size_t done_io; };

struct io_open { @@ -5417,12 +5418,21 @@ static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif + sr->done_io = 0; return 0; }

+static bool io_net_retry(struct socket *sock, int flags) +{ + if (!(flags & MSG_WAITALL)) + return false; + return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET; +} + static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_msghdr iomsg, *kmsg; + struct io_sr_msg *sr = &req->sr_msg; struct socket *sock; struct io_buffer *kbuf; unsigned flags; @@ -5465,6 +5475,10 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; + if (ret > 0 && io_net_retry(sock, flags)) { + sr->done_io += ret; + return io_setup_async_msg(req, kmsg); + } req_set_fail(req); } else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) { req_set_fail(req); @@ -5474,6 +5488,10 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) if (kmsg->free_iov) kfree(kmsg->free_iov); req->flags &= ~REQ_F_NEED_CLEANUP; + if (ret >= 0) + ret += sr->done_io; + else if (sr->done_io) + ret = sr->done_io; __io_req_complete(req, issue_flags, ret, io_put_kbuf(req, issue_flags)); return 0; } @@ -5524,12 +5542,22 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; + if (ret > 0 && io_net_retry(sock, flags)) { + sr->len -= ret; + sr->buf += ret; + sr->done_io += ret; + return -EAGAIN; + } req_set_fail(req); } else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) { out_free: req_set_fail(req); }

+ if (ret >= 0) + ret += sr->done_io; + else if (sr->done_io) + ret = sr->done_io; __io_req_complete(req, issue_flags, ret, io_put_kbuf(req, issue_flags)); return 0; }