[PATCH] io_uring: avoid implicit conversion to ktime_t

[Dmitry Antipov <dmantipov@yandex.ru>]

In 'io_get_ext_arg()', do not assume that 'min_wait_usec' of 'struct
io_uring_getevents_arg' (which is '__u32') multiplied by NSEC_PER_USEC
may be implicitly converted to 'ktime_t' but use the convenient
'us_to_ktime()' helper instead. Compile tested only.

Suggested-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
I didn't add Fixes: as per Jeff's remark at
https://lore.kernel.org/io-uring/x49ed01lkso.fsf@segfault.usersys.redhat.com/T/#t;
if you think that it should be, most likely they are:

aa00f67adc2c ("io_uring: add support for fixed wait regions")
7ed9e09e2d13 ("io_uring: wire up min batch wake timeout")
---
 io_uring/io_uring.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7f2500aca95c..f73555e981fa 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3257,7 +3257,7 @@ static int io_get_ext_arg(struct io_ring_ctx *ctx, unsigned flags,
 
 		if (w->flags & ~IORING_REG_WAIT_TS)
 			return -EINVAL;
-		ext_arg->min_time = READ_ONCE(w->min_wait_usec) * NSEC_PER_USEC;
+		ext_arg->min_time = us_to_ktime(READ_ONCE(w->min_wait_usec));
 		ext_arg->sig = u64_to_user_ptr(READ_ONCE(w->sigmask));
 		ext_arg->argsz = READ_ONCE(w->sigmask_sz);
 		if (w->flags & IORING_REG_WAIT_TS) {
@@ -3286,7 +3286,7 @@ static int io_get_ext_arg(struct io_ring_ctx *ctx, unsigned flags,
 	if (copy_from_user(&arg, uarg, sizeof(arg)))
 		return -EFAULT;
 #endif
-	ext_arg->min_time = arg.min_wait_usec * NSEC_PER_USEC;
+	ext_arg->min_time = us_to_ktime(arg.min_wait_usec);
 	ext_arg->sig = u64_to_user_ptr(arg.sigmask);
 	ext_arg->argsz = arg.sigmask_sz;
 	if (arg.ts) {
-- 
2.48.1