[PATCH 1/2] io_uring/cancel: count all requests that a CANCEL_ALL cancels

[Shang En Sim]

With IORING_ASYNC_CANCEL_ALL, __io_async_cancel() counts one for each
io_try_cancel() call that cancels something. io_futex_cancel() and
io_waitid_cancel() cancel every match in one call and return how many,
so four futex waits cancelled with CANCEL_ALL give a result of 1.

Add the number that they return.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 194bb58c6090 ("io_uring: add support for futex wake and wait")
Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support")
Signed-off-by: Shang En Sim <sim@xxxxxxxxxxx>
---
 io_uring/cancel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/io_uring/cancel.c b/io_uring/cancel.c
index 79b5c133319b..50a65fbc6ff0 100644
--- a/io_uring/cancel.c
+++ b/io_uring/cancel.c
@@ -198,7 +198,8 @@ static int __io_async_cancel(struct io_cancel_data *cd,
 			break;
 		if (!all)
 			return ret;
-		nr++;
+		/* futex and waitid return how many they cancelled */
+		nr += max(ret, 1);
 	} while (1);
 
 	/* slow path, try all io-wq's */
-- 
2.56.0