io_uring: do grab_env() just before punting

Currently io_steal_work() is disabled, and every linked request should
go through task_work for initialisation. Do io_req_work_grab_env()
just before io-wq punting and for the whole link, so any request
reachable by io_steal_work() is prepared.

This is also interesting for another reason -- it localises
io_req_work_grab_env() into one place just before io-wq punting, helping
to to better manage req->work lifetime and add some neat
cleanup/optimisations later.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-06-29 19:18:43 +03:00 committed by Jens Axboe
parent debb85f496
commit cbdcb4357c

View File

@ -1101,7 +1101,7 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx)
}
}
static inline void io_req_work_grab_env(struct io_kiocb *req)
static void io_req_work_grab_env(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
@ -1150,8 +1150,7 @@ static inline void io_req_work_drop_env(struct io_kiocb *req)
}
}
static inline void io_prep_async_work(struct io_kiocb *req,
struct io_kiocb **link)
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
@ -1164,15 +1163,22 @@ static inline void io_prep_async_work(struct io_kiocb *req,
}
io_req_work_grab_env(req);
*link = io_prep_linked_timeout(req);
}
static inline void io_queue_async_work(struct io_kiocb *req)
static void io_prep_async_link(struct io_kiocb *req)
{
struct io_kiocb *cur;
io_prep_async_work(req);
if (req->flags & REQ_F_LINK_HEAD)
list_for_each_entry(cur, &req->link_list, link_list)
io_prep_async_work(cur);
}
static void __io_queue_async_work(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *link;
io_prep_async_work(req, &link);
struct io_kiocb *link = io_prep_linked_timeout(req);
trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
&req->work, req->flags);
@ -1182,6 +1188,13 @@ static inline void io_queue_async_work(struct io_kiocb *req)
io_queue_linked_timeout(link);
}
static void io_queue_async_work(struct io_kiocb *req)
{
/* init ->work of the whole link before punting */
io_prep_async_link(req);
__io_queue_async_work(req);
}
static void io_kill_timeout(struct io_kiocb *req)
{
int ret;
@ -1215,7 +1228,8 @@ static void __io_queue_deferred(struct io_ring_ctx *ctx)
if (req_need_defer(req))
break;
list_del_init(&req->list);
io_queue_async_work(req);
/* punt-init is done before queueing for defer */
__io_queue_async_work(req);
} while (!list_empty(&ctx->defer_list));
}
@ -1791,7 +1805,7 @@ static void io_put_req(struct io_kiocb *req)
static struct io_wq_work *io_steal_work(struct io_kiocb *req)
{
struct io_kiocb *nxt = NULL;
struct io_kiocb *timeout, *nxt = NULL;
/*
* A ref is owned by io-wq in which context we're. So, if that's the
@ -1805,18 +1819,10 @@ static struct io_wq_work *io_steal_work(struct io_kiocb *req)
if (!nxt)
return NULL;
if ((nxt->flags & REQ_F_ISREG) && io_op_defs[nxt->opcode].hash_reg_file)
io_wq_hash_work(&nxt->work, file_inode(nxt->file));
io_req_task_queue(nxt);
/*
* If we're going to return actual work, here should be timeout prep:
*
* link = io_prep_linked_timeout(nxt);
* if (link)
* nxt->flags |= REQ_F_QUEUE_TIMEOUT;
*/
return NULL;
timeout = io_prep_linked_timeout(nxt);
if (timeout)
nxt->flags |= REQ_F_QUEUE_TIMEOUT;
return &nxt->work;
}
/*
@ -5369,8 +5375,8 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
ret = io_req_defer_prep(req, sqe);
if (ret < 0)
return ret;
io_req_work_grab_env(req);
}
io_prep_async_link(req);
spin_lock_irq(&ctx->completion_lock);
if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
@ -5984,7 +5990,6 @@ fail_req:
ret = io_req_defer_prep(req, sqe);
if (unlikely(ret < 0))
goto fail_req;
io_req_work_grab_env(req);
}
/*