[PATCH v2 03/13] io_uring: don't put nodes under spinlocks

Pavel Begunkov
2023-04-04T12:41:02Z

io_req_put_rsrc() doesn't need any locking, so move it out of
a spinlock section in __io_req_complete_post() and adjust helpers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
io_uring/io_uring.c | 7 +++++--
io_uring/rsrc.h | 6 +++---
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index a0b64831c455..596af20cddb4 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -970,6 +970,7 @@ bool io_aux_cqe(struct io_ring_ctx *ctx, bool defer, u64 user_data, s32 res, u32
static void __io_req_complete_post(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
+ struct io_rsrc_node *rsrc_node = NULL;

io_cq_lock(ctx);
if (!(req->flags & REQ_F_CQE_SKIP))
@@ -990,7 +991,7 @@ static void __io_req_complete_post(struct io_kiocb *req)
}
io_put_kbuf_comp(req);
io_dismantle_req(req);
- io_req_put_rsrc(req);
+ rsrc_node = req->rsrc_node;
/*
* Selected buffer deallocation in io_clean_op() assumes that
* we don't hold ->completion_lock. Clean them here to avoid
@@ -1001,6 +1002,8 @@ static void __io_req_complete_post(struct io_kiocb *req)
ctx->locked_free_nr++;
}
io_cq_unlock_post(ctx);
+
+ io_put_rsrc_node(rsrc_node);
}

void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
@@ -1117,7 +1120,7 @@ __cold void io_free_req(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;

- io_req_put_rsrc(req);
+ io_put_rsrc_node(req->rsrc_node);
io_dismantle_req(req);
io_put_task_remote(req->task, 1);

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 950535e2b9f4..8164777279ba 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -115,10 +115,10 @@ static inline void io_rsrc_put_node(struct io_rsrc_node *node, int nr)
io_rsrc_node_ref_zero(node);
}

-static inline void io_req_put_rsrc(struct io_kiocb *req)
+static inline void io_put_rsrc_node(struct io_rsrc_node *node)
{
- if (req->rsrc_node)
- io_rsrc_put_node(req->rsrc_node, 1);
+ if (node)
+ io_rsrc_put_node(node, 1);
}

static inline void io_req_put_rsrc_locked(struct io_kiocb *req,
--
2.39.1