On 9/8/20 7:45 AM, Jens Axboe wrote:
> On 9/8/20 7:29 AM, Jens Axboe wrote:
>> Hi,
>>
>> Can I get these two queued up, in this order:
>>
>> commit b7ddce3cbf010edbfac6c6d8cc708560a7bcd7a4
>> Author: Pavel Begunkov <asml.silence@xxxxxxxxx>
>> Date: Sun Sep 6 00:45:14 2020 +0300
>>
>> io_uring: fix cancel of deferred reqs with ->files
>>
>> and
>>
>> commit c127a2a1b7baa5eb40a7e2de4b7f0c51ccbbb2ef (tag: io_uring-5.9-2020-09-06, origin/i
>> o_uring-5.9, io_uring-5.9)
>> Author: Pavel Begunkov <asml.silence@xxxxxxxxx>
>> Date: Sun Sep 6 00:45:15 2020 +0300
>>
>> io_uring: fix linked deferred ->files cancellation
>>
>> which should both cherry-pick cleanly into the 5.8-stable tree.
>
> They do pick cleanly, but missing some infrastructure... I'll send these
> in separately.
Here you go, these work and are tested.
--
Jens Axboe
>From faaff9b554082ef41acdb314b920ea03b5ce95c9 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Sun, 6 Sep 2020 00:45:15 +0300
Subject: [PATCH 2/2] io_uring: fix linked deferred ->files cancellation
[ Upstream commit c127a2a1b7baa5eb40a7e2de4b7f0c51ccbbb2ef ]
While looking for ->files in ->defer_list, consider that requests there
may actually be links.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io_uring.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e1c11925d9ec..b69dd3be7522 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7600,6 +7600,28 @@ static bool io_match_link(struct io_kiocb *preq, struct io_kiocb *req)
return false;
}
+static inline bool io_match_files(struct io_kiocb *req,
+ struct files_struct *files)
+{
+ return (req->flags & REQ_F_WORK_INITIALIZED) && req->work.files == files;
+}
+
+static bool io_match_link_files(struct io_kiocb *req,
+ struct files_struct *files)
+{
+ struct io_kiocb *link;
+
+ if (io_match_files(req, files))
+ return true;
+ if (req->flags & REQ_F_LINK_HEAD) {
+ list_for_each_entry(link, &req->link_list, link_list) {
+ if (io_match_files(link, files))
+ return true;
+ }
+ }
+ return false;
+}
+
/*
* We're looking to cancel 'req' because it's holding on to our files, but
* 'req' could be a link to another request. See if it is, and cancel that
@@ -7682,8 +7704,7 @@ static void io_cancel_defer_files(struct io_ring_ctx *ctx,
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry_reverse(req, &ctx->defer_list, list) {
- if ((req->flags & REQ_F_WORK_INITIALIZED)
- && req->work.files == files) {
+ if (io_match_link_files(req, files)) {
list_cut_position(&list, &ctx->defer_list, &req->list);
break;
}
--
2.28.0
>From 02cad2a0bbbfe48aa575573deae15cc2431872ff Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Sun, 6 Sep 2020 00:45:14 +0300
Subject: [PATCH 1/2] io_uring: fix cancel of deferred reqs with ->files
[ Upstream commit b7ddce3cbf010edbfac6c6d8cc708560a7bcd7a4 ]
While trying to cancel requests with ->files, it also should look for
requests in ->defer_list, otherwise it might end up hanging a thread.
Cancel all requests in ->defer_list up to the last request there with
matching ->files, that's needed to follow drain ordering semantics.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io_uring.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index fe114511d6d6..e1c11925d9ec 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7674,12 +7674,38 @@ static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
io_timeout_remove_link(ctx, req);
}
+static void io_cancel_defer_files(struct io_ring_ctx *ctx,
+ struct files_struct *files)
+{
+ struct io_kiocb *req = NULL;
+ LIST_HEAD(list);
+
+ spin_lock_irq(&ctx->completion_lock);
+ list_for_each_entry_reverse(req, &ctx->defer_list, list) {
+ if ((req->flags & REQ_F_WORK_INITIALIZED)
+ && req->work.files == files) {
+ list_cut_position(&list, &ctx->defer_list, &req->list);
+ break;
+ }
+ }
+ spin_unlock_irq(&ctx->completion_lock);
+
+ while (!list_empty(&list)) {
+ req = list_first_entry(&list, struct io_kiocb, list);
+ list_del_init(&req->list);
+ req_set_fail_links(req);
+ io_cqring_add_event(req, -ECANCELED);
+ io_double_put_req(req);
+ }
+}
+
static void io_uring_cancel_files(struct io_ring_ctx *ctx,
struct files_struct *files)
{
if (list_empty_careful(&ctx->inflight_list))
return;
+ io_cancel_defer_files(ctx, files);
/* cancel all at once, should be faster than doing it one by one*/
io_wq_cancel_cb(ctx->io_wq, io_wq_files_match, files, true);
--
2.28.0
