workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 90 insertions, 0 deletions

diff --git a/io_uring/nop.c b/io_uring/nop.c
new file mode 100644
index 000000000..91ae0b2e7
--- /dev/null
+++ b/io_uring/nop.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "rsrc.h"
+#include "nop.h"
+
+struct io_nop {
+	struct file     *file;
+	int             result;
+	int		fd;
+	unsigned int	flags;
+	__u64		extra1;
+	__u64		extra2;
+};
+
+#define NOP_FLAGS	(IORING_NOP_INJECT_RESULT | IORING_NOP_FIXED_FILE | \
+			 IORING_NOP_FIXED_BUFFER | IORING_NOP_FILE | \
+			 IORING_NOP_TW | IORING_NOP_CQE32)
+
+int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
+
+	nop->flags = READ_ONCE(sqe->nop_flags);
+	if (nop->flags & ~NOP_FLAGS)
+		return -EINVAL;
+
+	if (nop->flags & IORING_NOP_INJECT_RESULT)
+		nop->result = READ_ONCE(sqe->len);
+	else
+		nop->result = 0;
+	if (nop->flags & IORING_NOP_FILE)
+		nop->fd = READ_ONCE(sqe->fd);
+	else
+		nop->fd = -1;
+	if (nop->flags & IORING_NOP_FIXED_BUFFER)
+		req->buf_index = READ_ONCE(sqe->buf_index);
+	if (nop->flags & IORING_NOP_CQE32) {
+		struct io_ring_ctx *ctx = req->ctx;
+
+		if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED)))
+			return -EINVAL;
+		nop->extra1 = READ_ONCE(sqe->off);
+		nop->extra2 = READ_ONCE(sqe->addr);
+	}
+	return 0;
+}
+
+int io_nop(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
+	int ret = nop->result;
+
+	if (nop->flags & IORING_NOP_FILE) {
+		if (nop->flags & IORING_NOP_FIXED_FILE) {
+			req->file = io_file_get_fixed(req, nop->fd, issue_flags);
+			req->flags |= REQ_F_FIXED_FILE;
+		} else {
+			req->file = io_file_get_normal(req, nop->fd);
+		}
+		if (!req->file) {
+			ret = -EBADF;
+			goto done;
+		}
+	}
+	if (nop->flags & IORING_NOP_FIXED_BUFFER) {
+		if (!io_find_buf_node(req, issue_flags))
+			ret = -EFAULT;
+	}
+done:
+	if (ret < 0)
+		req_set_fail(req);
+	if (nop->flags & IORING_NOP_CQE32)
+		io_req_set_res32(req, ret, 0, nop->extra1, nop->extra2);
+	else
+		io_req_set_res(req, ret, 0);
+	if (nop->flags & IORING_NOP_TW) {
+		req->io_task_work.func = io_req_task_complete;
+		io_req_task_work_add(req);
+		return IOU_ISSUE_SKIP_COMPLETE;
+	}
+	return IOU_COMPLETE;
+}