[RFC PATCH v2 1/2] io_uring: cmd: introduce io_uring_cmd_import_fixed_vec

[Sidong Yang]

io_uring_cmd_import_fixed_vec() could be used for using multiple
fixed buffer in uring_cmd callback.

Signed-off-by: Sidong Yang <sidong.yang@xxxxxxxxxx>
---
 include/linux/io_uring/cmd.h | 14 ++++++++++++++
 io_uring/uring_cmd.c         | 31 +++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
index 598cacda4aa3..b0e09c685941 100644
--- a/include/linux/io_uring/cmd.h
+++ b/include/linux/io_uring/cmd.h
@@ -44,6 +44,12 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 			      struct io_uring_cmd *ioucmd,
 			      unsigned int issue_flags);
 
+int io_uring_cmd_import_fixed_vec(struct io_uring_cmd *ioucmd,
+				  const struct iovec __user *uiovec,
+				  unsigned long nr_segs, int rw,
+				  unsigned int issue_flags,
+				  struct iov_iter *iter, struct bio_vec **bvec);
+
 /*
  * Completes the request, i.e. posts an io_uring CQE and deallocates @ioucmd
  * and the corresponding io_uring request.
@@ -76,6 +82,14 @@ io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 {
 	return -EOPNOTSUPP;
 }
+int io_uring_cmd_import_fixed_vec(struct io_uring_cmd *ioucmd,
+				  const struct iovec __user *uiovec,
+				  unsigned long nr_segs, int rw,
+				  unsigned int issue_flags,
+				  struct iov_iter *iter, struct bio_vec **bvec);
+{
+	return -EOPNOTSUPP;
+}
 static inline void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret,
 		u64 ret2, unsigned issue_flags)
 {
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index de39b602aa82..6bf076f45e6a 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include "linux/io_uring_types.h"
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/file.h>
@@ -255,6 +256,36 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 }
 EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
 
+int io_uring_cmd_import_fixed_vec(struct io_uring_cmd *ioucmd,
+				  const struct iovec __user *uiovec,
+				  unsigned long nr_segs, int rw,
+				  unsigned int issue_flags,
+				  struct iov_iter *iter, struct bio_vec **bvec)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+	struct iovec *iov;
+	int ret;
+	bool is_compat = io_is_compat(req->ctx);
+	struct iou_vec iou_vec;
+
+	if (!bvec)
+		return -EINVAL;
+
+	iov = iovec_from_user(uiovec, nr_segs, 0, NULL, is_compat);
+	if (IS_ERR(iov))
+		return PTR_ERR(iov);
+
+	iou_vec.iovec = iov;
+	iou_vec.nr = nr_segs;
+
+	ret = io_import_reg_vec(rw, iter, req, &iou_vec, iou_vec.nr, 0,
+				issue_flags);
+
+	*bvec = iou_vec.bvec;
+	return ret;
+}
+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);
-- 
2.43.0