From: Stefan Metzmacher <[email protected]>
To: [email protected]
Cc: Stefan Metzmacher <[email protected]>, [email protected]
Subject: [PATCH v2 1/1] io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL
Date: Sat, 20 Mar 2021 20:33:36 +0100 [thread overview]
Message-ID: <12efc18b6bef3955500080a238197e90ca6a402c.1616268538.git.metze@samba.org> (raw)
In-Reply-To: <c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.org>
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: [email protected]
Link: https://lore.kernel.org/r/c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.org
Signed-off-by: Stefan Metzmacher <[email protected]>
---
fs/io_uring.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 75b791ff21ec..746435e3f534 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4386,6 +4386,7 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
unsigned flags;
+ int min_ret = 0;
int ret;
sock = sock_from_file(req->file);
@@ -4406,6 +4407,9 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
else if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
+ if (flags & MSG_WAITALL)
+ min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN)
return io_setup_async_msg(req, kmsg);
@@ -4416,7 +4420,7 @@ static int io_sendmsg(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)
+ if (ret < min_ret)
req_set_fail_links(req);
__io_req_complete(req, issue_flags, ret, 0);
return 0;
@@ -4429,6 +4433,7 @@ static int io_send(struct io_kiocb *req, unsigned int issue_flags)
struct iovec iov;
struct socket *sock;
unsigned flags;
+ int min_ret = 0;
int ret;
sock = sock_from_file(req->file);
@@ -4450,6 +4455,9 @@ static int io_send(struct io_kiocb *req, unsigned int issue_flags)
else if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
+ if (flags & MSG_WAITALL)
+ min_ret = iov_iter_count(&msg.msg_iter);
+
msg.msg_flags = flags;
ret = sock_sendmsg(sock, &msg);
if ((issue_flags & IO_URING_F_NONBLOCK) && ret == -EAGAIN)
@@ -4457,7 +4465,7 @@ static int io_send(struct io_kiocb *req, unsigned int issue_flags)
if (ret == -ERESTARTSYS)
ret = -EINTR;
- if (ret < 0)
+ if (ret < min_ret)
req_set_fail_links(req);
__io_req_complete(req, issue_flags, ret, 0);
return 0;
@@ -4609,6 +4617,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
struct socket *sock;
struct io_buffer *kbuf;
unsigned flags;
+ int min_ret = 0;
int ret, cflags = 0;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
@@ -4640,6 +4649,9 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
else if (force_nonblock)
flags |= MSG_DONTWAIT;
+ if (flags & MSG_WAITALL)
+ min_ret = iov_iter_count(&kmsg->msg.msg_iter);
+
ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
kmsg->uaddr, flags);
if (force_nonblock && ret == -EAGAIN)
@@ -4653,7 +4665,7 @@ 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)
+ if (ret < min_ret || ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
req_set_fail_links(req);
__io_req_complete(req, issue_flags, ret, cflags);
return 0;
@@ -4668,6 +4680,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
struct socket *sock;
struct iovec iov;
unsigned flags;
+ int min_ret = 0;
int ret, cflags = 0;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
@@ -4699,6 +4712,9 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
else if (force_nonblock)
flags |= MSG_DONTWAIT;
+ if (flags & MSG_WAITALL)
+ min_ret = iov_iter_count(&msg.msg_iter);
+
ret = sock_recvmsg(sock, &msg, flags);
if (force_nonblock && ret == -EAGAIN)
return -EAGAIN;
@@ -4707,7 +4723,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags)
out_free:
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_recv_kbuf(req);
- if (ret < 0)
+ if (ret < min_ret || ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))))
req_set_fail_links(req);
__io_req_complete(req, issue_flags, ret, cflags);
return 0;
--
2.25.1
next prev parent reply other threads:[~2021-03-20 19:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 15:33 [PATCH 0/2] send[msg]()/recv[msg]() fixes/improvements Stefan Metzmacher
2021-03-16 15:33 ` [PATCH 1/2] io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() calls Stefan Metzmacher
2021-03-20 19:33 ` Stefan Metzmacher [this message]
2021-03-20 22:57 ` [PATCH v2 1/1] io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL Jens Axboe
2021-03-21 10:20 ` Stefan Metzmacher
2021-03-21 13:10 ` Jens Axboe
2021-03-16 15:33 ` [PATCH 2/2] io_uring: imply MSG_NOSIGNAL for send[msg]()/recv[msg]() calls Stefan Metzmacher
2021-03-17 22:36 ` [PATCH 0/2] send[msg]()/recv[msg]() fixes/improvements Jens Axboe
2021-03-17 23:07 ` Pavel Begunkov
2021-03-17 23:24 ` Jens Axboe
2021-03-17 23:26 ` Stefan Metzmacher
2021-03-17 23:39 ` Pavel Begunkov
2021-03-18 0:15 ` Stefan Metzmacher
2021-03-18 13:00 ` Pavel Begunkov
2021-03-18 13:08 ` Pavel Begunkov
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