[PATCHSET 0/2] Minor vectored futex cleanups

[PATCHSET 0/2] Minor vectored futex cleanups

[Jens Axboe]

Hi,

Wrote these a few months ago, but then apparently forgot about them...
Nothing major in here, mainly just splitting the "normal" and vectored
futex wait support data structures to clean up the code.

 io_uring/futex.c | 41 ++++++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 19 deletions(-)

-- 
Jens Axboe

[PATCH 1/2] io_uring/futex: move futexv async data handling to struct io_futexv_data

[Jens Axboe]

Rather than alloc an array of struct futex_vector for the futexv wait
handling, wrap it in a struct io_futexv_data struct, similar to what
the non-vectored futex wait handling does.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/futex.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/io_uring/futex.c b/io_uring/futex.c
index 4e022c76236d..bb3ae3e9c956 100644
--- a/io_uring/futex.c
+++ b/io_uring/futex.c
@@ -28,6 +28,10 @@ struct io_futex_data {
 	struct io_kiocb	*req;
 };
 
+struct io_futexv_data {
+	struct futex_vector	futexv[];
+};
+
 #define IO_FUTEX_ALLOC_CACHE_MAX	32
 
 bool io_futex_cache_init(struct io_ring_ctx *ctx)
@@ -62,14 +66,14 @@ static void io_futexv_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 {
 	struct io_kiocb *req = tw_req.req;
 	struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
-	struct futex_vector *futexv = req->async_data;
+	struct io_futexv_data *ifd = req->async_data;
 
 	io_tw_lock(req->ctx, tw);
 
 	if (!iof->futexv_unqueued) {
 		int res;
 
-		res = futex_unqueue_multiple(futexv, iof->futex_nr);
+		res = futex_unqueue_multiple(ifd->futexv, iof->futex_nr);
 		if (res != -1)
 			io_req_set_res(req, res, 0);
 	}
@@ -169,7 +173,7 @@ static void io_futex_wakev_fn(struct wake_q_head *wake_q, struct futex_q *q)
 int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
-	struct futex_vector *futexv;
+	struct io_futexv_data *ifd;
 	int ret;
 
 	/* No flags or mask supported for waitv */
@@ -182,14 +186,15 @@ int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (!iof->futex_nr || iof->futex_nr > FUTEX_WAITV_MAX)
 		return -EINVAL;
 
-	futexv = kcalloc(iof->futex_nr, sizeof(*futexv), GFP_KERNEL);
-	if (!futexv)
+	ifd = kzalloc(struct_size_t(struct io_futexv_data, futexv, iof->futex_nr),
+			GFP_KERNEL);
+	if (!ifd)
 		return -ENOMEM;
 
-	ret = futex_parse_waitv(futexv, iof->uaddr, iof->futex_nr,
+	ret = futex_parse_waitv(ifd->futexv, iof->uaddr, iof->futex_nr,
 				io_futex_wakev_fn, req);
 	if (ret) {
-		kfree(futexv);
+		kfree(ifd);
 		return ret;
 	}
 
@@ -198,7 +203,7 @@ int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	iof->futexv_owned = 0;
 	iof->futexv_unqueued = 0;
 	req->flags |= REQ_F_ASYNC_DATA;
-	req->async_data = futexv;
+	req->async_data = ifd;
 	return 0;
 }
 
@@ -218,13 +223,13 @@ static void io_futex_wake_fn(struct wake_q_head *wake_q, struct futex_q *q)
 int io_futexv_wait(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
-	struct futex_vector *futexv = req->async_data;
+	struct io_futexv_data *ifd = req->async_data;
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret, woken = -1;
 
 	io_ring_submit_lock(ctx, issue_flags);
 
-	ret = futex_wait_multiple_setup(futexv, iof->futex_nr, &woken);
+	ret = futex_wait_multiple_setup(ifd->futexv, iof->futex_nr, &woken);
 
 	/*
 	 * Error case, ret is < 0. Mark the request as failed.
-- 
2.51.0

[PATCH 2/2] io_uring/futex: move futexv owned status to struct io_futexv_data

[Jens Axboe]

Free up a bit of space in the shared futex opcode private data, by
moving the futexv specific futexv_owned out of there and into the struct
specific to vectored futexes.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/futex.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/io_uring/futex.c b/io_uring/futex.c
index bb3ae3e9c956..11bfff5a80df 100644
--- a/io_uring/futex.c
+++ b/io_uring/futex.c
@@ -17,7 +17,6 @@ struct io_futex {
 	void __user	*uaddr;
 	unsigned long	futex_val;
 	unsigned long	futex_mask;
-	unsigned long	futexv_owned;
 	u32		futex_flags;
 	unsigned int	futex_nr;
 	bool		futexv_unqueued;
@@ -29,6 +28,7 @@ struct io_futex_data {
 };
 
 struct io_futexv_data {
+	unsigned long		owned;
 	struct futex_vector	futexv[];
 };
 
@@ -82,10 +82,9 @@ static void io_futexv_complete(struct io_tw_req tw_req, io_tw_token_t tw)
 	__io_futex_complete(tw_req, tw);
 }
 
-static bool io_futexv_claim(struct io_futex *iof)
+static bool io_futexv_claim(struct io_futexv_data *ifd)
 {
-	if (test_bit(0, &iof->futexv_owned) ||
-	    test_and_set_bit_lock(0, &iof->futexv_owned))
+	if (test_bit(0, &ifd->owned) || test_and_set_bit_lock(0, &ifd->owned))
 		return false;
 	return true;
 }
@@ -100,9 +99,9 @@ static bool __io_futex_cancel(struct io_kiocb *req)
 			return false;
 		req->io_task_work.func = io_futex_complete;
 	} else {
-		struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
+		struct io_futexv_data *ifd = req->async_data;
 
-		if (!io_futexv_claim(iof))
+		if (!io_futexv_claim(ifd))
 			return false;
 		req->io_task_work.func = io_futexv_complete;
 	}
@@ -158,9 +157,9 @@ int io_futex_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 static void io_futex_wakev_fn(struct wake_q_head *wake_q, struct futex_q *q)
 {
 	struct io_kiocb *req = q->wake_data;
-	struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
+	struct io_futexv_data *ifd = req->async_data;
 
-	if (!io_futexv_claim(iof))
+	if (!io_futexv_claim(ifd))
 		return;
 	if (unlikely(!__futex_wake_mark(q)))
 		return;
@@ -200,7 +199,6 @@ int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 	/* Mark as inflight, so file exit cancelation will find it */
 	io_req_track_inflight(req);
-	iof->futexv_owned = 0;
 	iof->futexv_unqueued = 0;
 	req->flags |= REQ_F_ASYNC_DATA;
 	req->async_data = ifd;
-- 
2.51.0