rust: time: Add wrapper for fsleep() function

Add a wrapper for fsleep(), flexible sleep functions in
include/linux/delay.h which typically deals with hardware delays.

The kernel supports several sleep functions to handle various lengths
of delay. This adds fsleep(), automatically chooses the best sleep
method based on a duration.

fsleep() can only be used in a nonatomic context. This requirement is
not checked by these abstractions, but it is intended that klint [1]
or a similar tool will be used to check it in the future.

Link: https://rust-for-linux.com/klint [1]
Reviewed-by: Gary Guo <[email protected]>
Reviewed-by: Alice Ryhl <[email protected]>
Reviewed-by: Fiona Behrens <[email protected]>
Tested-by: Daniel Almeida <[email protected]>
Reviewed-by: Andreas Hindborg <[email protected]>
Signed-off-by: FUJITA Tomonori <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Andreas Hindborg <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/rust/helpers/time.c b/rust/helpers/time.c
index 08755db43fc2..a318e9fa4408 100644
--- a/rust/helpers/time.c
+++ b/rust/helpers/time.c
@@ -1,8 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/delay.h>
 #include <linux/ktime.h>
 #include <linux/timekeeping.h>
 
+void rust_helper_fsleep(unsigned long usecs)
+{
+	fsleep(usecs);
+}
+
 ktime_t rust_helper_ktime_get_real(void)
 {
 	return ktime_get_real();