Hello,
This RFC patchset adds sendto(2) and recvfrom(2) support for io_uring.
It also addresses an issue in the liburing GitHub repository [1].
## Motivations:
1) By using `sendto()` and `recvfrom()` we can make the submission
simpler compared to always using `sendmsg()` and `recvmsg()` from
the userspace.
2) There is a historical patch that tried to add the same
functionality, but did not end up being applied. [2]
On Tue, 7 Jul 2020 12:29:18 -0600, Jens Axboe <axboe@xxxxxxxxx> wrote:
> In a private conversation with the author, a good point was brought
> up that the sendto/recvfrom do not require an allocation of an async
> context, if we need to defer or go async with the request. I think
> that's a major win, to be honest. There are other benefits as well
> (like shorter path), but to me, the async less part is nice and will
> reduce overhead
## Changes summary
There are 3 patches in this series.
PATCH 1/3 renames io_recv to io_recvfrom and io_send to io_sendto.
Note that
send(sockfd, buf, len, flags);
is equivalent to
sendto(sockfd, buf, len, flags, NULL, 0);
and
recv(sockfd, buf, len, flags);
is equivalent to
recvfrom(sockfd, buf, len, flags, NULL, NULL);
So it is saner to have `send` and `recv` directed to `sendto` and
`recvfrom` instead of the opposite with respect to the name.
PATCH 2/3 makes `move_addr_to_user()` be a non static function. This
function lives in net/socket.c, we need to call this from io_uring
to add `recvfrom()` support for liburing. Added net files maintainers
to the CC list.
PATCH 3/3 adds `sendto(2)` and `recvfrom(2)` support for io_uring.
Added two new opcodes: IORING_OP_SENDTO and IORING_OP_RECVFROM.
## How to test
This patchset is based on "for-next" branch commit:
bb3294e22482db4b7ec7cfbb2d0f5b53c1adcf86 ("Merge branch 'for-5.17/drivers' into for-next")
It is also available in the Git repository at:
https://github.com/ammarfaizi2/linux-block ammarfaizi2/linux-block/io_uring-recvfrom-sendto
I also added the liburing support and test. The liburing support is
based on "xattr-getdents64" branch commit:
55a9bf979f27f3a5c9f456f26dcfe16c4791667b ("src/include/liburing.h: style cleanups")
It is available in the Git repository at:
https://github.com/ammarfaizi2/liburing sendto-recvfrom
---
v3:
- Fix build error when CONFIG_NET is undefined for PATCH 1/3. I
tried to fix it in PATCH 3/3, but it should be fixed in PATCH 1/3,
otherwise it breaks the build in PATCH 1/3.
- Added `io_uring_prep_{sendto,recvfrom}` docs to the liburing.
v2:
- Rebased the work, now this patchset is based on commit
bb3294e22482db4b7ec ("Merge branch 'for-5.17/drivers' into
for-next").
- In `io_recvfrom()`, mark the error check of `move_addr_to_user()`
call as unlikely.
- Fix build error when CONFIG_NET is undefined.
- Update liburing test (the branch is still the same, just force
pushed).
- Added Nugra to CC list (tester).
---
RFC v2: https://lore.kernel.org/io-uring/20211230114846.137954-1-ammar.faizi@xxxxxxxxx/
RFC v1: https://lore.kernel.org/io-uring/20211230013154.102910-1-ammar.faizi@xxxxxxxxx/
Link: https://github.com/axboe/liburing/issues/397 [1]
Link: https://lore.kernel.org/io-uring/a2399c89-2c45-375c-7395-b5caf556ec3d@xxxxxxxxx/ [2]
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: Nugra <richiisei@xxxxxxxxx>
Signed-off-by: Ammar Faizi <ammarfaizi2@xxxxxxxxx>
---
Ammar Faizi (3):
io_uring: Rename `io_{send,recv}` to `io_{sendto,recvfrom}`
net: Make `move_addr_to_user()` be a non static function
io_uring: Add `sendto(2)` and `recvfrom(2)` support
fs/io_uring.c | 92 +++++++++++++++++++++++++++++++----
include/linux/socket.h | 2 +
include/uapi/linux/io_uring.h | 2 +
net/socket.c | 4 +-
4 files changed, 88 insertions(+), 12 deletions(-)
base-commit: bb3294e22482db4b7ec7cfbb2d0f5b53c1adcf86
--
Ammar Faizi
