1 files changed, 400 insertions, 0 deletions
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
new file mode 100644
index 000000000000..197474911f04
--- /dev/null
+++ b/io_uring/uring_cmd.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/io_uring/cmd.h>
+#include <linux/security.h>
+#include <linux/nospec.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "alloc_cache.h"
+#include "rsrc.h"
+#include "kbuf.h"
+#include "uring_cmd.h"
+#include "poll.h"
+
+void io_cmd_cache_free(const void *entry)
+{
+	struct io_async_cmd *ac = (struct io_async_cmd *)entry;
+
+	io_vec_free(&ac->vec);
+	kfree(ac);
+}
+
+static void io_req_uring_cleanup(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	struct io_async_cmd *ac = req->async_data;
+
+	if (issue_flags & IO_URING_F_UNLOCKED)
+		return;
+
+	io_alloc_cache_vec_kasan(&ac->vec);
+	if (ac->vec.nr > IO_VEC_CACHE_SOFT_CAP)
+		io_vec_free(&ac->vec);
+
+	if (io_alloc_cache_put(&req->ctx->cmd_cache, ac)) {
+		ioucmd->sqe = NULL;
+		io_req_async_data_clear(req, REQ_F_NEED_CLEANUP);
+	}
+}
+
+void io_uring_cmd_cleanup(struct io_kiocb *req)
+{
+	io_req_uring_cleanup(req, 0);
+}
+
+bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
+				   struct io_uring_task *tctx, bool cancel_all)
+{
+	struct hlist_node *tmp;
+	struct io_kiocb *req;
+	bool ret = false;
+
+	lockdep_assert_held(&ctx->uring_lock);
+
+	hlist_for_each_entry_safe(req, tmp, &ctx->cancelable_uring_cmd,
+			hash_node) {
+		struct io_uring_cmd *cmd = io_kiocb_to_cmd(req,
+				struct io_uring_cmd);
+		struct file *file = req->file;
+
+		if (!cancel_all && req->tctx != tctx)
+			continue;
+
+		if (cmd->flags & IORING_URING_CMD_CANCELABLE) {
+			file->f_op->uring_cmd(cmd, IO_URING_F_CANCEL |
+						   IO_URING_F_COMPLETE_DEFER);
+			ret = true;
+		}
+	}
+	io_submit_flush_completions(ctx);
+	return ret;
+}
+
+static void io_uring_cmd_del_cancelable(struct io_uring_cmd *cmd,
+		unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(cmd);
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!(cmd->flags & IORING_URING_CMD_CANCELABLE))
+		return;
+
+	cmd->flags &= ~IORING_URING_CMD_CANCELABLE;
+	io_ring_submit_lock(ctx, issue_flags);
+	hlist_del(&req->hash_node);
+	io_ring_submit_unlock(ctx, issue_flags);
+}
+
+/*
+ * Mark this command as concelable, then io_uring_try_cancel_uring_cmd()
+ * will try to cancel this issued command by sending ->uring_cmd() with
+ * issue_flags of IO_URING_F_CANCEL.
+ *
+ * The command is guaranteed to not be done when calling ->uring_cmd()
+ * with IO_URING_F_CANCEL, but it is driver's responsibility to deal
+ * with race between io_uring canceling and normal completion.
+ */
+void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
+		unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(cmd);
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!(cmd->flags & IORING_URING_CMD_CANCELABLE)) {
+		cmd->flags |= IORING_URING_CMD_CANCELABLE;
+		io_ring_submit_lock(ctx, issue_flags);
+		hlist_add_head(&req->hash_node, &ctx->cancelable_uring_cmd);
+		io_ring_submit_unlock(ctx, issue_flags);
+	}
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable);
+
+void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
+			io_req_tw_func_t task_work_cb,
+			unsigned flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+	if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
+		return;
+
+	req->io_task_work.func = task_work_cb;
+	__io_req_task_work_add(req, flags);
+}
+EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task);
+
+static inline void io_req_set_cqe32_extra(struct io_kiocb *req,
+					  u64 extra1, u64 extra2)
+{
+	req->big_cqe.extra1 = extra1;
+	req->big_cqe.extra2 = extra2;
+}
+
+/*
+ * Called by consumers of io_uring_cmd, if they originally returned
+ * -EIOCBQUEUED upon receiving the command.
+ */
+void __io_uring_cmd_done(struct io_uring_cmd *ioucmd, s32 ret, u64 res2,
+		       unsigned issue_flags, bool is_cqe32)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+	if (WARN_ON_ONCE(req->flags & REQ_F_APOLL_MULTISHOT))
+		return;
+
+	io_uring_cmd_del_cancelable(ioucmd, issue_flags);
+
+	if (ret < 0)
+		req_set_fail(req);
+
+	io_req_set_res(req, ret, 0);
+	if (is_cqe32) {
+		if (req->ctx->flags & IORING_SETUP_CQE_MIXED)
+			req->cqe.flags |= IORING_CQE_F_32;
+		io_req_set_cqe32_extra(req, res2, 0);
+	}
+	io_req_uring_cleanup(req, issue_flags);
+	if (req->ctx->flags & IORING_SETUP_IOPOLL) {
+		/* order with io_iopoll_req_issued() checking ->iopoll_complete */
+		smp_store_release(&req->iopoll_completed, 1);
+	} else if (issue_flags & IO_URING_F_COMPLETE_DEFER) {
+		if (WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED))
+			return;
+		io_req_complete_defer(req);
+	} else {
+		req->io_task_work.func = io_req_task_complete;
+		io_req_task_work_add(req);
+	}
+}
+EXPORT_SYMBOL_GPL(__io_uring_cmd_done);
+
+int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	struct io_async_cmd *ac;
+
+	if (sqe->__pad1)
+		return -EINVAL;
+
+	ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
+	if (ioucmd->flags & ~IORING_URING_CMD_MASK)
+		return -EINVAL;
+
+	if (ioucmd->flags & IORING_URING_CMD_FIXED) {
+		if (ioucmd->flags & IORING_URING_CMD_MULTISHOT)
+			return -EINVAL;
+		req->buf_index = READ_ONCE(sqe->buf_index);
+	}
+
+	if (!!(ioucmd->flags & IORING_URING_CMD_MULTISHOT) !=
+	    !!(req->flags & REQ_F_BUFFER_SELECT))
+		return -EINVAL;
+
+	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
+
+	ac = io_uring_alloc_async_data(&req->ctx->cmd_cache, req);
+	if (!ac)
+		return -ENOMEM;
+	ioucmd->sqe = sqe;
+	return 0;
+}
+
+/*
+ * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
+ * slot.
+ */
+static inline size_t uring_sqe_size(struct io_kiocb *req)
+{
+	if (req->ctx->flags & IORING_SETUP_SQE128 ||
+	    req->opcode == IORING_OP_URING_CMD128)
+		return 2 * sizeof(struct io_uring_sqe);
+	return sizeof(struct io_uring_sqe);
+}
+
+void io_uring_cmd_sqe_copy(struct io_kiocb *req)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	struct io_async_cmd *ac = req->async_data;
+
+	/* Should not happen, as REQ_F_SQE_COPIED covers this */
+	if (WARN_ON_ONCE(ioucmd->sqe == ac->sqes))
+		return;
+	memcpy(ac->sqes, ioucmd->sqe, uring_sqe_size(req));
+	ioucmd->sqe = ac->sqes;
+}
+
+int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	struct io_ring_ctx *ctx = req->ctx;
+	struct file *file = req->file;
+	int ret;
+
+	if (!file->f_op->uring_cmd)
+		return -EOPNOTSUPP;
+
+	ret = security_uring_cmd(ioucmd);
+	if (ret)
+		return ret;
+
+	if (ctx->flags & IORING_SETUP_SQE128 ||
+	    req->opcode == IORING_OP_URING_CMD128)
+		issue_flags |= IO_URING_F_SQE128;
+	if (ctx->flags & (IORING_SETUP_CQE32 | IORING_SETUP_CQE_MIXED))
+		issue_flags |= IO_URING_F_CQE32;
+	if (io_is_compat(ctx))
+		issue_flags |= IO_URING_F_COMPAT;
+	if (ctx->flags & IORING_SETUP_IOPOLL) {
+		if (!file->f_op->uring_cmd_iopoll)
+			return -EOPNOTSUPP;
+		issue_flags |= IO_URING_F_IOPOLL;
+		req->iopoll_completed = 0;
+		if (ctx->flags & IORING_SETUP_HYBRID_IOPOLL) {
+			/* make sure every req only blocks once */
+			req->flags &= ~REQ_F_IOPOLL_STATE;
+			req->iopoll_start = ktime_get_ns();
+		}
+	}
+
+	ret = file->f_op->uring_cmd(ioucmd, issue_flags);
+	if (ioucmd->flags & IORING_URING_CMD_MULTISHOT) {
+		if (ret >= 0)
+			return IOU_ISSUE_SKIP_COMPLETE;
+	}
+	if (ret == -EAGAIN) {
+		ioucmd->flags |= IORING_URING_CMD_REISSUE;
+		return ret;
+	}
+	if (ret == -EIOCBQUEUED)
+		return ret;
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_uring_cleanup(req, issue_flags);
+	io_req_set_res(req, ret, 0);
+	return IOU_COMPLETE;
+}
+
+int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
+			      struct iov_iter *iter,
+			      struct io_uring_cmd *ioucmd,
+			      unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+	if (WARN_ON_ONCE(!(ioucmd->flags & IORING_URING_CMD_FIXED)))
+		return -EINVAL;
+
+	return io_import_reg_buf(req, iter, ubuf, len, rw, issue_flags);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
+
+int io_uring_cmd_import_fixed_vec(struct io_uring_cmd *ioucmd,
+				  const struct iovec __user *uvec,
+				  size_t uvec_segs,
+				  int ddir, struct iov_iter *iter,
+				  unsigned issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+	struct io_async_cmd *ac = req->async_data;
+	int ret;
+
+	if (WARN_ON_ONCE(!(ioucmd->flags & IORING_URING_CMD_FIXED)))
+		return -EINVAL;
+
+	ret = io_prep_reg_iovec(req, &ac->vec, uvec, uvec_segs);
+	if (ret)
+		return ret;
+
+	return io_import_reg_vec(ddir, iter, req, &ac->vec, uvec_segs,
+				 issue_flags);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed_vec);
+
+void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+	io_req_queue_iowq(req);
+}
+
+int io_cmd_poll_multishot(struct io_uring_cmd *cmd,
+			  unsigned int issue_flags, __poll_t mask)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(cmd);
+	int ret;
+
+	if (likely(req->flags & REQ_F_APOLL_MULTISHOT))
+		return 0;
+
+	req->flags |= REQ_F_APOLL_MULTISHOT;
+	mask &= ~EPOLLONESHOT;
+
+	ret = io_arm_apoll(req, issue_flags, mask);
+	return ret == IO_APOLL_OK ? -EIOCBQUEUED : -ECANCELED;
+}
+
+bool io_uring_cmd_post_mshot_cqe32(struct io_uring_cmd *cmd,
+				   unsigned int issue_flags,
+				   struct io_uring_cqe cqe[2])
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(cmd);
+
+	if (WARN_ON_ONCE(!(issue_flags & IO_URING_F_MULTISHOT)))
+		return false;
+	return io_req_post_cqe32(req, cqe);
+}
+
+/*
+ * Work with io_uring_mshot_cmd_post_cqe() together for committing the
+ * provided buffer upfront
+ */
+struct io_br_sel io_uring_cmd_buffer_select(struct io_uring_cmd *ioucmd,
+					    unsigned buf_group, size_t *len,
+					    unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+	if (!(ioucmd->flags & IORING_URING_CMD_MULTISHOT))
+		return (struct io_br_sel) { .val = -EINVAL };
+
+	if (WARN_ON_ONCE(!io_do_buffer_select(req)))
+		return (struct io_br_sel) { .val = -EINVAL };
+
+	return io_buffer_select(req, len, buf_group, issue_flags);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_buffer_select);
+
+/*
+ * Return true if this multishot uring_cmd needs to be completed, otherwise
+ * the event CQE is posted successfully.
+ *
+ * This function must use `struct io_br_sel` returned from
+ * io_uring_cmd_buffer_select() for committing the buffer in the same
+ * uring_cmd submission context.
+ */
+bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
+				 struct io_br_sel *sel, unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+	unsigned int cflags = 0;
+
+	if (!(ioucmd->flags & IORING_URING_CMD_MULTISHOT))
+		return true;
+
+	if (sel->val > 0) {
+		cflags = io_put_kbuf(req, sel->val, sel->buf_list);
+		if (io_req_post_cqe(req, sel->val, cflags | IORING_CQE_F_MORE))
+			return false;
+	}
+
+	io_kbuf_recycle(req, sel->buf_list, issue_flags);
+	if (sel->val < 0)
+		req_set_fail(req);
+	io_req_set_res(req, sel->val, cflags);
+	return true;
+}
+EXPORT_SYMBOL_GPL(io_uring_mshot_cmd_post_cqe);