Re: [PATCH v2] treewide, serdev: change receive_buf() return type to size_t

On Mon, Jan 22, 2024 at 07:05:51PM +0100, Francesco Dolcini wrote:

From: Francesco Dolcini <redacted>

receive_buf() is called from ttyport_receive_buf() that expects values
">= 0" from serdev_controller_receive_buf(), change its return type from
ssize_t to size_t.

The need for this clean-up was noticed while fixing a warning, see
commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value").
Changing the callback prototype to return an unsigned seems the best way
to document the API and ensure that is properly used.

GNSS drivers implementation of serdev receive_buf() callback return
directly the return value of gnss_insert_raw(). gnss_insert_raw()
returns a signed int, however this is not an issue since the value
returned is always positive, because of the kfifo_in() implementation.
gnss_insert_raw() could be changed to return also an unsigned, however
this is not implemented here as request by the GNSS maintainer Johan
Hovold.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/ (local)
Signed-off-by: Francesco Dolcini <redacted>
Acked-by: Jonathan Cameron <redacted> #for-iio
---
v1:
 - https://lore.kernel.org/all/20231214170146.641783-1-francesco@dolcini.it/ (local)
v2:
 - rebased on 6.8-rc1
 - add acked-by Jonathan
 - do not change gnss_insert_raw()
 - do not change the code style of the gnss code
 - commit message improvements, explain the reasons for doing only minimal
   changes on the GNSS part

Looks good to me now:

Reviewed-by: Johan Hovold <johan@kernel.org>