[PATCH 06/17] io_uring: prep for fixed-buffer enabled uring-cmd

[Kanchan Joshi <joshi.k@xxxxxxxxxxx>]

From: Anuj Gupta <anuj20.g@xxxxxxxxxxx>

Refactor the existing code and factor out helper that can be used for
passthrough with fixed-buffer. This is a prep patch.

Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
---
 fs/io_uring.c            | 19 ++++++++++++++-----
 include/linux/io_uring.h |  7 +++++++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1f228a79e68f..ead0cbae8416 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3140,11 +3140,10 @@ static void kiocb_done(struct io_kiocb *req, ssize_t ret,
 	}
 }
 
-static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
-			     struct io_mapped_ubuf *imu)
+static int __io_import_fixed(u64 buf_addr, size_t len, int rw,
+			struct iov_iter *iter, struct io_mapped_ubuf *imu)
 {
-	size_t len = req->rw.len;
-	u64 buf_end, buf_addr = req->rw.addr;
+	u64 buf_end;
 	size_t offset;
 
 	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
@@ -3213,9 +3212,19 @@ static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter)
 		imu = READ_ONCE(ctx->user_bufs[index]);
 		req->imu = imu;
 	}
-	return __io_import_fixed(req, rw, iter, imu);
+	return __io_import_fixed(req->rw.addr, req->rw.len, rw, iter, imu);
 }
 
+int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len,
+		int rw, struct iov_iter *iter, void *ioucmd)
+{
+	struct io_kiocb *req = container_of(ioucmd, struct io_kiocb, uring_cmd);
+	struct io_mapped_ubuf *imu = req->imu;
+
+	return __io_import_fixed(ubuf, len, rw, iter, imu);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
+
 static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock)
 {
 	if (needs_lock)
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index cedc68201469..1888a5ea7dbe 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -25,6 +25,8 @@ struct io_uring_cmd {
 };
 
 #if defined(CONFIG_IO_URING)
+int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len,
+		int rw, struct iov_iter *iter, void *ioucmd);
 void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret);
 void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
 			void (*driver_cb)(struct io_uring_cmd *));
@@ -48,6 +50,11 @@ static inline void io_uring_free(struct task_struct *tsk)
 		__io_uring_free(tsk);
 }
 #else
+int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len,
+		int rw, struct iov_iter *iter, void *ioucmd)
+{
+	return -1;
+}
 static inline void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret)
 {
 }
-- 
2.25.1