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io_uring: fix cancel of deferred reqs with ->files 

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@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
zero-sugar-mainline-defconfig
Pavel Begunkov 2020-09-06 00:45:14 +03:00 committed by Jens Axboe
parent c183edff33
commit b7ddce3cbf
1 changed files with 27 additions and 0 deletions
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27
fs/io_uring.c
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@ -8098,12 +8098,39 @@ 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);