[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <e61f29ecdfac2a0f42a45971a3ab586710084d97.1748607147.git.asml.silence@gmail.com>
Date: Fri, 30 May 2025 13:18:21 +0100
From: Pavel Begunkov <asml.silence@...il.com>
To: io-uring@...r.kernel.org,
Vadim Fedorenko <vadim.fedorenko@...ux.dev>
Cc: asml.silence@...il.com,
netdev@...r.kernel.org,
Eric Dumazet <edumazet@...gle.com>,
Kuniyuki Iwashima <kuniyu@...zon.com>,
Paolo Abeni <pabeni@...hat.com>,
Willem de Bruijn <willemb@...gle.com>,
"David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Richard Cochran <richardcochran@...il.com>
Subject: [PATCH 3/5] io_uring/cmd: allow multishot polled commands
Some commands like timestamping in the next patch can make use of
multishot polling, i.e. REQ_F_APOLL_MULTISHOT. Add support for that,
which is condensed in a single helper called io_cmd_poll_multishot().
The user who wants to continue with a request in a multishot mode must
call the function, and only if it returns 0 the user is free to proceed.
Apart from normal terminal errors, it can also end up with -EIOCBQUEUED,
in which case the user must forward it to the core io_uring. It's
forbidden to use task work while the request is executing in a multishot
mode.
The API is not foolproof, hence it's not exported to modules nor exposed
in public headers.
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
io_uring/uring_cmd.c | 23 +++++++++++++++++++++++
io_uring/uring_cmd.h | 3 +++
2 files changed, 26 insertions(+)
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 929cad6ee326..2710521eec62 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -12,6 +12,7 @@
#include "alloc_cache.h"
#include "rsrc.h"
#include "uring_cmd.h"
+#include "poll.h"
void io_cmd_cache_free(const void *entry)
{
@@ -136,6 +137,9 @@ void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+ if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
+ return;
+
ioucmd->task_work_cb = task_work_cb;
req->io_task_work.func = io_uring_cmd_work;
__io_req_task_work_add(req, flags);
@@ -158,6 +162,9 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, u64 res2,
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+ if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
+ return;
+
io_uring_cmd_del_cancelable(ioucmd, issue_flags);
if (ret < 0)
@@ -310,3 +317,19 @@ void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd)
io_req_queue_iowq(req);
}
+
+int io_cmd_poll_multishot(struct io_uring_cmd *cmd,
+ unsigned int issue_flags, __poll_t mask)
+{
+ struct io_kiocb *req = cmd_to_io_kiocb(cmd);
+ int ret;
+
+ if (likely(req->flags & REQ_F_APOLL_MULTISHOT))
+ return 0;
+
+ req->flags |= REQ_F_APOLL_MULTISHOT;
+ mask &= ~EPOLLONESHOT;
+
+ ret = io_arm_apoll(req, issue_flags, mask);
+ return ret == IO_APOLL_OK ? -EIOCBQUEUED : -ECANCELED;
+}
diff --git a/io_uring/uring_cmd.h b/io_uring/uring_cmd.h
index e6a5142c890e..9565ca5d5cf2 100644
--- a/io_uring/uring_cmd.h
+++ b/io_uring/uring_cmd.h
@@ -17,3 +17,6 @@ bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
struct io_uring_task *tctx, bool cancel_all);
void io_cmd_cache_free(const void *entry);
+
+int io_cmd_poll_multishot(struct io_uring_cmd *cmd,
+ unsigned int issue_flags, __poll_t mask);
--
2.49.0
Powered by blists - more mailing lists