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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: Pavel Begunkov <[email protected]>, Jens Axboe <[email protected]>
Subject: [PATCH 14/33] io_uring: destroy io-wq on exec
Date: Wed,  3 Mar 2021 17:26:41 -0700	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

From: Pavel Begunkov <[email protected]>

Destroy current's io-wq backend and tctx on __io_uring_task_cancel(),
aka exec(). Looks it's not strictly necessary, because it will be done
at some point when the task dies and changes of creds/files/etc. are
handled, but better to do that earlier to free io-wq and not potentially
lock previous mm and other resources for the time being.

It's safe to do because we wait for all requests of the current task to
complete, so no request will use tctx afterwards. Note, that
io_uring_files_cancel() may leave some requests for later reaping, so it
leaves tctx intact, that's ok as the task is dying anyway.

Signed-off-by: Pavel Begunkov <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 fs/io_uring.c            | 19 ++++++++++---------
 include/linux/io_uring.h |  2 +-
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d495735de2d9..4afe3dd1430c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8835,13 +8835,17 @@ static void io_uring_del_task_file(struct file *file)
 		fput(file);
 }
 
-static void io_uring_remove_task_files(struct io_uring_task *tctx)
+static void io_uring_clean_tctx(struct io_uring_task *tctx)
 {
 	struct file *file;
 	unsigned long index;
 
 	xa_for_each(&tctx->xa, index, file)
 		io_uring_del_task_file(file);
+	if (tctx->io_wq) {
+		io_wq_put_and_exit(tctx->io_wq);
+		tctx->io_wq = NULL;
+	}
 }
 
 void __io_uring_files_cancel(struct files_struct *files)
@@ -8856,13 +8860,8 @@ void __io_uring_files_cancel(struct files_struct *files)
 		io_uring_cancel_task_requests(file->private_data, files);
 	atomic_dec(&tctx->in_idle);
 
-	if (files) {
-		io_uring_remove_task_files(tctx);
-		if (tctx->io_wq) {
-			io_wq_put_and_exit(tctx->io_wq);
-			tctx->io_wq = NULL;
-		}
-	}
+	if (files)
+		io_uring_clean_tctx(tctx);
 }
 
 static s64 tctx_inflight(struct io_uring_task *tctx)
@@ -8954,7 +8953,9 @@ void __io_uring_task_cancel(void)
 
 	atomic_dec(&tctx->in_idle);
 
-	io_uring_remove_task_files(tctx);
+	io_uring_clean_tctx(tctx);
+	/* all current's requests should be gone, we can kill tctx */
+	__io_uring_free(current);
 }
 
 void __io_uring_unshare(void)
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index bfe2fcb4f478..796e0d7d186d 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -44,7 +44,7 @@ static inline void io_uring_unshare(void)
 }
 static inline void io_uring_task_cancel(void)
 {
-	if (current->io_uring && !xa_empty(&current->io_uring->xa))
+	if (current->io_uring)
 		__io_uring_task_cancel();
 }
 static inline void io_uring_files_cancel(struct files_struct *files)
-- 
2.30.1


  parent reply	other threads:[~2021-03-04  1:10 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04  0:26 [PATCHSET 0/33] Fixes queued up for 5.12 Jens Axboe
2021-03-04  0:26 ` [PATCH 01/33] io-wq: wait for worker startup when forking a new one Jens Axboe
2021-03-04  0:26 ` [PATCH 02/33] io-wq: have manager wait for all workers to exit Jens Axboe
2021-03-04  0:26 ` [PATCH 03/33] io-wq: don't ask for a new worker if we're exiting Jens Axboe
2021-03-04  0:26 ` [PATCH 04/33] io-wq: rename wq->done completion to wq->started Jens Axboe
2021-03-04  0:26 ` [PATCH 05/33] io-wq: wait for manager exit on wq destroy Jens Axboe
2021-03-04  0:26 ` [PATCH 06/33] io-wq: fix double put of 'wq' in error path Jens Axboe
2021-03-04  0:26 ` [PATCH 07/33] io_uring: SQPOLL stop error handling fixes Jens Axboe
2021-03-04  0:26 ` [PATCH 08/33] io_uring: run fallback on cancellation Jens Axboe
2021-03-04  0:26 ` [PATCH 09/33] io_uring: don't use complete_all() on SQPOLL thread exit Jens Axboe
2021-03-04  0:26 ` [PATCH 10/33] io-wq: provide an io_wq_put_and_exit() helper Jens Axboe
2021-03-04  0:26 ` [PATCH 11/33] io_uring: fix race condition in task_work add and clear Jens Axboe
2021-03-04  0:26 ` [PATCH 12/33] io_uring: signal worker thread unshare Jens Axboe
2021-03-04 12:15   ` Stefan Metzmacher
2021-03-04 14:05     ` Jens Axboe
2021-03-04  0:26 ` [PATCH 13/33] io_uring: warn on not destroyed io-wq Jens Axboe
2021-03-04  0:26 ` Jens Axboe [this message]
2021-03-04  0:26 ` [PATCH 15/33] io_uring: remove unused argument 'tsk' from io_req_caches_free() Jens Axboe
2021-03-04  0:26 ` [PATCH 16/33] io_uring: kill unnecessary REQ_F_WORK_INITIALIZED checks Jens Axboe
2021-03-04  0:26 ` [PATCH 17/33] io_uring: move cred assignment into io_issue_sqe() Jens Axboe
2021-03-04  0:26 ` [PATCH 18/33] io_uring: kill unnecessary io_run_ctx_fallback() in io_ring_exit_work() Jens Axboe
2021-03-04  0:26 ` [PATCH 19/33] io_uring: kill io_uring_flush() Jens Axboe
2021-03-04  0:26 ` [PATCH 20/33] io_uring: fix __tctx_task_work() ctx race Jens Axboe
2021-03-04  0:26 ` [PATCH 21/33] io_uring: replace cmpxchg in fallback with xchg Jens Axboe
2021-03-04  0:26 ` [PATCH 22/33] io_uring: ensure that SQPOLL thread is started for exit Jens Axboe
2021-03-04  0:26 ` [PATCH 23/33] io_uring: ignore double poll add on the same waitqueue head Jens Axboe
2021-03-04  0:26 ` [PATCH 24/33] io_uring: kill sqo_dead and sqo submission halting Jens Axboe
2021-03-04  0:26 ` [PATCH 25/33] io_uring: remove sqo_task Jens Axboe
2021-03-04  0:26 ` [PATCH 26/33] io-wq: fix error path leak of buffered write hash map Jens Axboe
2021-03-04  0:26 ` [PATCH 27/33] io_uring: fix -EAGAIN retry with IOPOLL Jens Axboe
2021-03-04  0:26 ` [PATCH 28/33] io_uring: choose right tctx->io_wq for try cancel Jens Axboe
2021-03-04  0:26 ` [PATCH 29/33] io_uring: inline io_req_clean_work() Jens Axboe
2021-03-04  0:26 ` [PATCH 30/33] io_uring: inline __io_queue_async_work() Jens Axboe
2021-03-04  0:26 ` [PATCH 31/33] io_uring: remove extra in_idle wake up Jens Axboe
2021-03-04  0:26 ` [PATCH 32/33] io_uring: ensure that threads freeze on suspend Jens Axboe
2021-03-04  0:27 ` [PATCH 33/33] io-wq: ensure all pending work is canceled on exit Jens Axboe

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