* [PATCH 1/2] io_uring: fix cancel of deferred reqs with ->files
2020-09-05 21:45 [PATCH for-5.9 0/2] fix deferred ->files cancel Pavel Begunkov
@ 2020-09-05 21:45 ` Pavel Begunkov
2020-09-05 21:45 ` [PATCH 2/2] io_uring: fix linked deferred ->files cancellation Pavel Begunkov
2020-09-05 22:03 ` [PATCH for-5.9 0/2] fix deferred ->files cancel Jens Axboe
2 siblings, 0 replies; 4+ messages in thread
From: Pavel Begunkov @ 2020-09-05 21:45 UTC (permalink / raw)
To: Jens Axboe, io-uring
While trying to cancel requests with ->files, it also should look for 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 <[email protected]>
---
fs/io_uring.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2e3adf9d17dd..20b647afe206 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8092,12 +8092,38 @@ 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_defer_entry *de = NULL;
+ LIST_HEAD(list);
+
+ spin_lock_irq(&ctx->completion_lock);
+ list_for_each_entry_reverse(de, &ctx->defer_list, list)
+ if ((de->req->flags & REQ_F_WORK_INITIALIZED)
+ && de->req->work.files == files) {
+ list_cut_position(&list, &ctx->defer_list, &de->list);
+ break;
+ }
+ spin_unlock_irq(&ctx->completion_lock);
+
+ while (!list_empty(&list)) {
+ de = list_first_entry(&list, struct io_defer_entry, list);
+ list_del_init(&de->list);
+ req_set_fail_links(de->req);
+ io_put_req(de->req);
+ io_req_complete(de->req, -ECANCELED);
+ kfree(de);
+ }
+}
+
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);
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] io_uring: fix linked deferred ->files cancellation
2020-09-05 21:45 [PATCH for-5.9 0/2] fix deferred ->files cancel Pavel Begunkov
2020-09-05 21:45 ` [PATCH 1/2] io_uring: fix cancel of deferred reqs with ->files Pavel Begunkov
@ 2020-09-05 21:45 ` Pavel Begunkov
2020-09-05 22:03 ` [PATCH for-5.9 0/2] fix deferred ->files cancel Jens Axboe
2 siblings, 0 replies; 4+ messages in thread
From: Pavel Begunkov @ 2020-09-05 21:45 UTC (permalink / raw)
To: Jens Axboe, io-uring
While looking for ->files in ->defer_list, consider that requests there
may actually be links.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 20b647afe206..f56e2cad97cc 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8018,6 +8018,26 @@ 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 *file)
+{
+ return (req->flags & REQ_F_WORK_INITIALIZED) && req->work.files == file;
+}
+
+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
@@ -8100,8 +8120,7 @@ static void io_cancel_defer_files(struct io_ring_ctx *ctx,
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry_reverse(de, &ctx->defer_list, list)
- if ((de->req->flags & REQ_F_WORK_INITIALIZED)
- && de->req->work.files == files) {
+ if (io_match_link_files(de->req, files)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH for-5.9 0/2] fix deferred ->files cancel
2020-09-05 21:45 [PATCH for-5.9 0/2] fix deferred ->files cancel Pavel Begunkov
2020-09-05 21:45 ` [PATCH 1/2] io_uring: fix cancel of deferred reqs with ->files Pavel Begunkov
2020-09-05 21:45 ` [PATCH 2/2] io_uring: fix linked deferred ->files cancellation Pavel Begunkov
@ 2020-09-05 22:03 ` Jens Axboe
2 siblings, 0 replies; 4+ messages in thread
From: Jens Axboe @ 2020-09-05 22:03 UTC (permalink / raw)
To: Pavel Begunkov, io-uring
On 9/5/20 3:45 PM, Pavel Begunkov wrote:
> io_uring_cancel_files() may hangs because it can't find requests with
> ->files in defer_list.
Thanks! Applied with a few style changes.
--
Jens Axboe
^ permalink raw reply [flat|nested] 4+ messages in thread