[PATCH] io_uring: fix compile error when CONFIG_IO_URING not set

[lingfuyi]

when compile with ARCH=mips CROSS_COMPILE=mips-linux-gnu- , and CONFIG_IO_URING
is not set , compile will case some error like this:
drivers/nvme/host/ioctl.c:555:37: error: initialization of
‘const struct nvme_uring_cmd *’ from ‘int’ makes pointer from
integer without a cast [-Werror=int-conversion]

Reported-by: k2ci <kernel-bot@xxxxxxxxxx>
Signed-off-by: lingfuyi <lingfuyi@xxxxxxx>
---
 include/linux/io_uring.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 7fe31b2cd02f..c76809f59617 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -98,6 +98,10 @@ static inline void io_uring_files_cancel(void)
 static inline void io_uring_free(struct task_struct *tsk)
 {
 }
+static inline const void *io_uring_sqe_cmd(const struct io_uring_sqe *sqe)
+{
+       return NULL;
+}
 static inline const char *io_uring_get_opcode(u8 opcode)
 {
 	return "";
-- 
2.20.1