[PATCH] engines/io_uring: Fix negative errno in io_u->error

[PATCH] engines/io_uring: Fix negative errno in io_u->error

[Minwoo Im]

io_u->error can have either negative errno value or device-specific
error status as a positive value.  fio always tries to parse the errno
with strerrno() and it expects the value to be a positive one.

Commit ebe67b667f25 ("io_uring: Add IO_U_F_DEVICE_ERRROR to identify
error types") tried to abs(io_u->error) to convert it first.  And it
caused the following build warning:

  engines/io_uring.c:553:16: error: taking the absolute value of unsigned type 'unsigned int' has no effect [-Werror,-Wabsolute-value]
          io_u->error = abs(io_u->error);
                        ^
  engines/io_uring.c:553:16: note: remove the call to 'abs' since unsigned values cannot be negative
          io_u->error = abs(io_u->error);
                        ^~~

Commit 9eaa8e7c8e0b ("engines/io_uring: don't use abs() on an unsigned
value") tried to remove the warning by removing abs() on io_u->error,
but if so, negative errno (e.g., -EINVAL) can't be parsed properly like:

  fio: io_u error on file /dev/ng0n1: Unknown error -22: write offset=429916160, buflen=1048576

This patch fixed this fixed to convert to positive value properly by
casting it first to int and then do abs() on it.

Fixes: 9eaa8e7c8e0b ("engines/io_uring: don't use abs() on an unsigned value")

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
---
 engines/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/engines/io_uring.c b/engines/io_uring.c
index 6c07c1011c40..85cebf8371cf 100644
--- a/engines/io_uring.c
+++ b/engines/io_uring.c
@@ -589,7 +589,7 @@ ret:
 		io_u_set(td, io_u, IO_U_F_DEVICE_ERROR);
 	else
 		io_u_clear(td, io_u, IO_U_F_DEVICE_ERROR);
-	io_u->error = io_u->error;
+	io_u->error = abs((int)io_u->error);
 	return io_u;
 }
 
-- 
2.34.1

Re: [PATCH] engines/io_uring: Fix negative errno in io_u->error

[Jens Axboe]

On Fri, 27 Sep 2024 12:08:57 +0900, Minwoo Im wrote:
> io_u->error can have either negative errno value or device-specific
> error status as a positive value.  fio always tries to parse the errno
> with strerrno() and it expects the value to be a positive one.
> 
> Commit ebe67b667f25 ("io_uring: Add IO_U_F_DEVICE_ERRROR to identify
> error types") tried to abs(io_u->error) to convert it first.  And it
> caused the following build warning:
> 
> [...]

Applied, thanks!

[1/1] engines/io_uring: Fix negative errno in io_u->error
      commit: e4e8520b374e7e021d289d400ade70c41681d635

Best regards,
-- 
Jens Axboe