io_uring: add io_uring_cmd_import_fixed

This is a new helper that callers can use to obtain a bvec iterator for
the previously mapped buffer. This is preparatory work to enable
fixed-buffer support for io_uring_cmd.

Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-2-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 58676c0..1dbf511 100644 (file)
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -4,6 +4,7 @@
 
 #include <linux/sched.h>
 #include <linux/xarray.h>
+#include <uapi/linux/io_uring.h>
 
 enum io_uring_cmd_flags {
        IO_URING_F_COMPLETE_DEFER       = 1,
@@ -32,6 +33,8 @@ 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, ssize_t res2);
 void io_uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
                        void (*task_work_cb)(struct io_uring_cmd *));
@@ -59,6 +62,11 @@ static inline void io_uring_free(struct task_struct *tsk)
                __io_uring_free(tsk);
 }
 #else
+static int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
+                             struct iov_iter *iter, void *ioucmd)
+{
+       return -EOPNOTSUPP;
+}
 static inline void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret,
                ssize_t ret2)
 {

diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index f3ed61e..6a6d695 100644 (file)
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -8,6 +8,7 @@
 #include <uapi/linux/io_uring.h>
 
 #include "io_uring.h"
+#include "rsrc.h"
 #include "uring_cmd.h"
 
 static void io_uring_cmd_work(struct io_kiocb *req, bool *locked)
@@ -129,3 +130,12 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
 
        return IOU_ISSUE_SKIP_COMPLETE;
 }
+
+int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
+                             struct iov_iter *iter, void *ioucmd)
+{
+       struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+
+       return io_import_fixed(rw, iter, req->imu, ubuf, len);
+}
+EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);