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io_uring: cleanup up cancel SQPOLL reqs across exec

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For SQPOLL rings tctx_inflight() always returns zero, so it might skip
doing full cancelation. It's fine because we jam all sqpoll submissions
in any case and do go through files cancel for them, but not nice.

Do the intended full cancellation, by mimicking __io_uring_task_cancel()
waiting but impersonating SQPOLL task.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-02-07 22:34:26 +00:00 committed by Jens Axboe
parent 257e84a537
commit 0e9ddb39b7
1 changed files with 36 additions and 21 deletions
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57
fs/io_uring.c
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@ -9083,29 +9083,39 @@ void __io_uring_files_cancel(struct files_struct *files)
static s64 tctx_inflight(struct io_uring_task *tctx)
{
unsigned long index;
struct file *file;
return percpu_counter_sum(&tctx->inflight);
}
static void io_uring_cancel_sqpoll(struct io_ring_ctx *ctx)
{
struct io_uring_task *tctx;
s64 inflight;
DEFINE_WAIT(wait);
inflight = percpu_counter_sum(&tctx->inflight);
if (!tctx->sqpoll)
return inflight;
if (!ctx->sq_data)
return;
tctx = ctx->sq_data->thread->io_uring;
io_disable_sqo_submit(ctx);
/*
* If we have SQPOLL rings, then we need to iterate and find them, and
* add the pending count for those.
*/
xa_for_each(&tctx->xa, index, file) {
struct io_ring_ctx *ctx = file->private_data;
atomic_inc(&tctx->in_idle);
do {
/* read completions before cancelations */
inflight = tctx_inflight(tctx);
if (!inflight)
break;
io_uring_cancel_task_requests(ctx, NULL);
if (ctx->flags & IORING_SETUP_SQPOLL) {
struct io_uring_task *__tctx = ctx->sqo_task->io_uring;
inflight += percpu_counter_sum(&__tctx->inflight);
}
}
return inflight;
prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
/*
* If we've seen completions, retry without waiting. This
* avoids a race where a completion comes in before we did
* prepare_to_wait().
*/
if (inflight == tctx_inflight(tctx))
schedule();
finish_wait(&tctx->wait, &wait);
} while (1);
atomic_dec(&tctx->in_idle);
}
/*
@ -9122,8 +9132,13 @@ void __io_uring_task_cancel(void)
atomic_inc(&tctx->in_idle);
/* trigger io_disable_sqo_submit() */
if (tctx->sqpoll)
__io_uring_files_cancel(NULL);
if (tctx->sqpoll) {
struct file *file;
unsigned long index;
xa_for_each(&tctx->xa, index, file)
io_uring_cancel_sqpoll(file->private_data);
}
do {
/* read completions before cancelations */