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

[Sidong Yang <sidong.yang@furiosa.ai>]

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@furiosa.ai>
---
 include/linux/io_uring/cmd.h | 14 ++++++++++++++
 io_uring/uring_cmd.c         | 29 +++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
index 598cacda4aa3..75cf25c1e730 100644
--- a/include/linux/io_uring/cmd.h
+++ b/include/linux/io_uring/cmd.h
@@ -44,6 +44,13 @@ 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(const struct iovec __user *uiovec,
+				  unsigned long nr_segs, int rw,
+				  struct iov_iter *iter,
+				  struct io_uring_cmd *ioucmd,
+				  struct iou_vec *iou_vec, bool compat,
+				  unsigned int issue_flags);
+
 /*
  * Completes the request, i.e. posts an io_uring CQE and deallocates @ioucmd
  * and the corresponding io_uring request.
@@ -76,6 +83,13 @@ io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 {
 	return -EOPNOTSUPP;
 }
+int io_uring_cmd_import_fixed_vec(int rw, struct iov_iter *iter,
+				  struct io_uring_cmd *ioucmd,
+				  struct iou_vec *vec, unsigned nr_iovs,
+				  unsigned iovec_off, unsigned int issue_flags)
+{
+	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..58e2932f29e7 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -255,6 +255,35 @@ 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(const struct iovec __user *uiovec,
+				  unsigned long nr_segs, int rw,
+				  struct iov_iter *iter,
+				  struct io_uring_cmd *ioucmd,
+				  struct iou_vec *iou_vec, bool compat,
+				  unsigned int issue_flags)
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+	struct iovec *iov;
+	int ret;
+
+	iov = iovec_from_user(uiovec, nr_segs, 0, NULL, compat);
+	if (IS_ERR(iov))
+		return PTR_ERR(iov);
+
+	ret = io_vec_realloc(iou_vec, nr_segs);
+	if (ret) {
+		kfree(iov);
+		return ret;
+	}
+	memcpy(iou_vec->iovec, iov, sizeof(*iov) * nr_segs);
+	kfree(iov);
+
+	ret = io_import_reg_vec(rw, iter, req, iou_vec, iou_vec->nr, 0,
+				issue_flags);
+	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