io_uring: move struct io_kiocb from task_struct to io_uring_task

Rather than store the task_struct itself in struct io_kiocb, store
the io_uring specific task_struct. The life times are the same in terms
of io_uring, and this avoids doing some dereferences through the
task_struct. For the hot path of putting local task references, we can
deref req->tctx instead, which we'll need anyway in that function
regardless of whether it's local or remote references.

This is mostly straight forward, except the original task PF_EXITING
check needs a bit of tweaking. task_work is _always_ run from the
originating task, except in the fallback case, where it's run from a
kernel thread. Replace the potentially racy (in case of fallback work)
checks for req->task->flags with current->flags. It's either the still
the original task, in which case PF_EXITING will be sane, or it has
PF_KTHREAD set, in which case it's fallback work. Both cases should
prevent moving forward with the given request.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
index 8da0d9e4533a..efbec34ccb18 100644
--- a/io_uring/fdinfo.c
+++ b/io_uring/fdinfo.c
@@ -203,7 +203,7 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file)
 
 		hlist_for_each_entry(req, &hb->list, hash_node)
 			seq_printf(m, "  op=%d, task_works=%d\n", req->opcode,
-					task_work_pending(req->task));
+					task_work_pending(req->tctx->task));
 	}
 
 	if (has_lock)