* [PATCH 1/2] io_uring: kill sqo_dead and sqo submission halting
2021-03-01 13:02 [PATCH 5.12 0/2] kill sqo_dead Pavel Begunkov
@ 2021-03-01 13:02 ` Pavel Begunkov
2021-03-01 14:42 ` Jens Axboe
2021-03-01 13:02 ` [PATCH 2/2] io_uring: remove sqo_task Pavel Begunkov
1 sibling, 1 reply; 4+ messages in thread
From: Pavel Begunkov @ 2021-03-01 13:02 UTC (permalink / raw)
To: Jens Axboe, io-uring
As SQPOLL task doesn't poke into ->sqo_task anymore, there is no need to
kill the sqo when the master task exits. Before it was necessary to
avoid races accessing sqo_task->files with removing them.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 40 +++-------------------------------------
1 file changed, 3 insertions(+), 37 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 54e6c4db9620..6529761b77eb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -338,7 +338,6 @@ struct io_ring_ctx {
unsigned int drain_next: 1;
unsigned int eventfd_async: 1;
unsigned int restricted: 1;
- unsigned int sqo_dead: 1;
unsigned int sqo_exec: 1;
/*
@@ -1972,7 +1971,7 @@ static void __io_req_task_submit(struct io_kiocb *req)
/* ctx stays valid until unlock, even if we drop all ours ctx->refs */
mutex_lock(&ctx->uring_lock);
- if (!ctx->sqo_dead && !(current->flags & PF_EXITING) && !current->in_execve)
+ if (!(current->flags & PF_EXITING) && !current->in_execve)
__io_queue_sqe(req);
else
__io_req_task_cancel(req, -EFAULT);
@@ -6583,8 +6582,7 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
if (!list_empty(&ctx->iopoll_list))
io_do_iopoll(ctx, &nr_events, 0);
- if (to_submit && !ctx->sqo_dead &&
- likely(!percpu_ref_is_dying(&ctx->refs)))
+ if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)))
ret = io_submit_sqes(ctx, to_submit);
mutex_unlock(&ctx->uring_lock);
}
@@ -7823,7 +7821,7 @@ static int io_sq_thread_fork(struct io_sq_data *sqd, struct io_ring_ctx *ctx)
clear_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
reinit_completion(&sqd->completion);
- ctx->sqo_dead = ctx->sqo_exec = 0;
+ ctx->sqo_exec = 0;
sqd->task_pid = current->pid;
current->flags |= PF_IO_WORKER;
ret = io_wq_fork_thread(io_sq_thread, sqd);
@@ -8534,10 +8532,6 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
-
- if (WARN_ON_ONCE((ctx->flags & IORING_SETUP_SQPOLL) && !ctx->sqo_dead))
- ctx->sqo_dead = 1;
-
/* if force is set, the ring is going away. always drop after that */
ctx->cq_overflow_flushed = 1;
if (ctx->rings)
@@ -8697,19 +8691,6 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
}
}
-static void io_disable_sqo_submit(struct io_ring_ctx *ctx)
-{
- mutex_lock(&ctx->uring_lock);
- ctx->sqo_dead = 1;
- if (ctx->flags & IORING_SETUP_R_DISABLED)
- io_sq_offload_start(ctx);
- mutex_unlock(&ctx->uring_lock);
-
- /* make sure callers enter the ring to get error */
- if (ctx->rings)
- io_ring_set_wakeup_flag(ctx);
-}
-
/*
* We need to iteratively cancel requests, in case a request has dependent
* hard links. These persist even for failure of cancelations, hence keep
@@ -8722,7 +8703,6 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
bool did_park = false;
if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
- io_disable_sqo_submit(ctx);
did_park = io_sq_thread_park(ctx->sq_data);
if (did_park) {
task = ctx->sq_data->thread;
@@ -8843,7 +8823,6 @@ static void io_uring_cancel_sqpoll(struct io_ring_ctx *ctx)
if (!sqd)
return;
- io_disable_sqo_submit(ctx);
if (!io_sq_thread_park(sqd))
return;
tctx = ctx->sq_data->thread->io_uring;
@@ -8888,7 +8867,6 @@ void __io_uring_task_cancel(void)
/* make sure overflow events are dropped */
atomic_inc(&tctx->in_idle);
- /* trigger io_disable_sqo_submit() */
if (tctx->sqpoll) {
struct file *file;
unsigned long index;
@@ -9019,22 +8997,14 @@ static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
do {
if (!io_sqring_full(ctx))
break;
-
prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
- if (unlikely(ctx->sqo_dead)) {
- ret = -EOWNERDEAD;
- goto out;
- }
-
if (!io_sqring_full(ctx))
break;
-
schedule();
} while (!signal_pending(current));
finish_wait(&ctx->sqo_sq_wait, &wait);
-out:
return ret;
}
@@ -9120,8 +9090,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
goto out;
}
ret = -EOWNERDEAD;
- if (unlikely(ctx->sqo_dead))
- goto out;
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT) {
@@ -9493,7 +9461,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
*/
ret = io_uring_install_fd(ctx, file);
if (ret < 0) {
- io_disable_sqo_submit(ctx);
/* fput will clean it up */
fput(file);
return ret;
@@ -9502,7 +9469,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
- io_disable_sqo_submit(ctx);
io_ring_ctx_wait_and_kill(ctx);
return ret;
}
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/2] io_uring: remove sqo_task
2021-03-01 13:02 [PATCH 5.12 0/2] kill sqo_dead Pavel Begunkov
2021-03-01 13:02 ` [PATCH 1/2] io_uring: kill sqo_dead and sqo submission halting Pavel Begunkov
@ 2021-03-01 13:02 ` Pavel Begunkov
1 sibling, 0 replies; 4+ messages in thread
From: Pavel Begunkov @ 2021-03-01 13:02 UTC (permalink / raw)
To: Jens Axboe, io-uring
Now, sqo_task is used only for a warning that is not interesting anymore
since sqo_dead is gone, remove all of that including ctx->sqo_task.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6529761b77eb..7fb284ce5319 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -379,11 +379,6 @@ struct io_ring_ctx {
struct io_rings *rings;
- /*
- * For SQPOLL usage
- */
- struct task_struct *sqo_task;
-
/* Only used for accounting purposes */
struct mm_struct *mm_account;
@@ -8747,10 +8742,6 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
fput(file);
return ret;
}
-
- /* one and only SQPOLL file note, held by sqo_task */
- WARN_ON_ONCE((ctx->flags & IORING_SETUP_SQPOLL) &&
- current != ctx->sqo_task);
}
tctx->last = file;
}
@@ -9398,7 +9389,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
ctx->compat = in_compat_syscall();
if (!capable(CAP_IPC_LOCK))
ctx->user = get_uid(current_user());
- ctx->sqo_task = current;
/*
* This is just grabbed for accounting purposes. When a process exits,
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread