Thread (9 messages) 9 messages, 8 authors, 2024-03-25
STALE852d LANDED

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

From: Francesco Dolcini <francesco@dolcini.it>
Date: 2024-01-22 18:06:05
Also in: chrome-platform, linux-arm-kernel, linux-bluetooth, linux-iio, linux-mediatek, linux-serial, linux-sound, lkml, platform-driver-x86
Subsystem: bluetooth drivers, chrome hardware platform support, chromeos ec uart driver, gnss subsystem, greybus beagleplay drivers, greybus subsystem, iio subsystem and drivers, mediatek bluetooth driver, microsoft surface hardware platform support, microsoft surface system aggregator subsystem, multifunction devices (mfd), networking drivers, nfc subsystem, nxp bluetooth wireless drivers, plantower pms7003 air pollution sensor driver, qualcomm atheros qca7k ethernet driver, sensirion scd30 carbon dioxide sensor driver, sensirion sps30 air pollution sensor driver, serial device bus, sound, the rest, tty layer and serial drivers · Maintainers: Marcel Holtmann, Luiz Augusto von Dentz, Benson Leung, Tzung-Bi Shih, Bhanu Prakash Maiya, Johan Hovold, Ayush Singh, Alex Elder, Greg Kroah-Hartman, Jonathan Cameron, Sean Wang, Hans de Goede, Ilpo Järvinen, Maximilian Luz, Lee Jones, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Heidelberg, Amitkumar Karwar, Neeraj Kale, Tomasz Duszynski, Stefan Wahren, Maxwell Doose, Rob Herring, Jaroslav Kysela, Takashi Iwai, Linus Torvalds, Jiri Slaby

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 <Jonathan.Cameron@huawei.com> #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
---
 drivers/bluetooth/btmtkuart.c              |  4 ++--
 drivers/bluetooth/btnxpuart.c              |  4 ++--
 drivers/bluetooth/hci_serdev.c             |  4 ++--
 drivers/gnss/serial.c                      |  2 +-
 drivers/gnss/sirf.c                        |  2 +-
 drivers/greybus/gb-beagleplay.c            |  6 +++---
 drivers/iio/chemical/pms7003.c             |  4 ++--
 drivers/iio/chemical/scd30_serial.c        |  4 ++--
 drivers/iio/chemical/sps30_serial.c        |  4 ++--
 drivers/iio/imu/bno055/bno055_ser_core.c   |  4 ++--
 drivers/mfd/rave-sp.c                      |  4 ++--
 drivers/net/ethernet/qualcomm/qca_uart.c   |  2 +-
 drivers/nfc/pn533/uart.c                   |  4 ++--
 drivers/nfc/s3fwrn5/uart.c                 |  4 ++--
 drivers/platform/chrome/cros_ec_uart.c     |  4 ++--
 drivers/platform/surface/aggregator/core.c |  4 ++--
 drivers/tty/serdev/serdev-ttyport.c        | 10 ++++------
 include/linux/serdev.h                     |  8 ++++----
 sound/drivers/serial-generic.c             |  4 ++--
 19 files changed, 40 insertions(+), 42 deletions(-)
diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c
index 3c84fcbda01a..e6bc4a73c9fc 100644
--- a/drivers/bluetooth/btmtkuart.c
+++ b/drivers/bluetooth/btmtkuart.c
@@ -383,8 +383,8 @@ static void btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
 	}
 }
 
-static ssize_t btmtkuart_receive_buf(struct serdev_device *serdev,
-				     const u8 *data, size_t count)
+static size_t btmtkuart_receive_buf(struct serdev_device *serdev,
+				    const u8 *data, size_t count)
 {
 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
 
diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 1d592ac413d1..056bef5b2919 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -1264,8 +1264,8 @@ static const struct h4_recv_pkt nxp_recv_pkts[] = {
 	{ NXP_RECV_FW_REQ_V3,   .recv = nxp_recv_fw_req_v3 },
 };
 
-static ssize_t btnxpuart_receive_buf(struct serdev_device *serdev,
-				     const u8 *data, size_t count)
+static size_t btnxpuart_receive_buf(struct serdev_device *serdev,
+				    const u8 *data, size_t count)
 {
 	struct btnxpuart_dev *nxpdev = serdev_device_get_drvdata(serdev);
 
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index 39c8b567da3c..a3c3beb2806d 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -271,8 +271,8 @@ static void hci_uart_write_wakeup(struct serdev_device *serdev)
  *
  * Return: number of processed bytes
  */
-static ssize_t hci_uart_receive_buf(struct serdev_device *serdev,
-				    const u8 *data, size_t count)
+static size_t hci_uart_receive_buf(struct serdev_device *serdev,
+				   const u8 *data, size_t count)
 {
 	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
 
diff --git a/drivers/gnss/serial.c b/drivers/gnss/serial.c
index baa956494e79..0e43bf6294f8 100644
--- a/drivers/gnss/serial.c
+++ b/drivers/gnss/serial.c
@@ -80,7 +80,7 @@ static const struct gnss_operations gnss_serial_gnss_ops = {
 	.write_raw	= gnss_serial_write_raw,
 };
 
-static ssize_t gnss_serial_receive_buf(struct serdev_device *serdev,
+static size_t gnss_serial_receive_buf(struct serdev_device *serdev,
 				       const u8 *buf, size_t count)
 {
 	struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c
index 6801a8fb2040..79375d14bbb6 100644
--- a/drivers/gnss/sirf.c
+++ b/drivers/gnss/sirf.c
@@ -160,7 +160,7 @@ static const struct gnss_operations sirf_gnss_ops = {
 	.write_raw	= sirf_write_raw,
 };
 
-static ssize_t sirf_receive_buf(struct serdev_device *serdev,
+static size_t sirf_receive_buf(struct serdev_device *serdev,
 				const u8 *buf, size_t count)
 {
 	struct sirf_data *data = serdev_device_get_drvdata(serdev);
diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c
index c3e90025064b..33f8fad70260 100644
--- a/drivers/greybus/gb-beagleplay.c
+++ b/drivers/greybus/gb-beagleplay.c
@@ -271,7 +271,7 @@ static void hdlc_rx_frame(struct gb_beagleplay *bg)
 	}
 }
 
-static ssize_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count)
+static size_t hdlc_rx(struct gb_beagleplay *bg, const u8 *data, size_t count)
 {
 	size_t i;
 	u8 c;
@@ -331,8 +331,8 @@ static void hdlc_deinit(struct gb_beagleplay *bg)
 	flush_work(&bg->tx_work);
 }
 
-static ssize_t gb_tty_receive(struct serdev_device *sd, const u8 *data,
-			      size_t count)
+static size_t gb_tty_receive(struct serdev_device *sd, const u8 *data,
+			     size_t count)
 {
 	struct gb_beagleplay *bg = serdev_device_get_drvdata(sd);
 
diff --git a/drivers/iio/chemical/pms7003.c b/drivers/iio/chemical/pms7003.c
index b5cf15a515d2..43025866d5b7 100644
--- a/drivers/iio/chemical/pms7003.c
+++ b/drivers/iio/chemical/pms7003.c
@@ -211,8 +211,8 @@ static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
 	return checksum == pms7003_calc_checksum(frame);
 }
 
-static ssize_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf,
-				   size_t size)
+static size_t pms7003_receive_buf(struct serdev_device *serdev, const u8 *buf,
+				  size_t size)
 {
 	struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
 	struct pms7003_state *state = iio_priv(indio_dev);
diff --git a/drivers/iio/chemical/scd30_serial.c b/drivers/iio/chemical/scd30_serial.c
index a47654591e55..2adb76dbb020 100644
--- a/drivers/iio/chemical/scd30_serial.c
+++ b/drivers/iio/chemical/scd30_serial.c
@@ -174,8 +174,8 @@ static int scd30_serdev_command(struct scd30_state *state, enum scd30_cmd cmd, u
 	return 0;
 }
 
-static ssize_t scd30_serdev_receive_buf(struct serdev_device *serdev,
-					const u8 *buf, size_t size)
+static size_t scd30_serdev_receive_buf(struct serdev_device *serdev,
+				       const u8 *buf, size_t size)
 {
 	struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
 	struct scd30_serdev_priv *priv;
diff --git a/drivers/iio/chemical/sps30_serial.c b/drivers/iio/chemical/sps30_serial.c
index 3afa89f8acc3..a6dfbe28c914 100644
--- a/drivers/iio/chemical/sps30_serial.c
+++ b/drivers/iio/chemical/sps30_serial.c
@@ -210,8 +210,8 @@ static int sps30_serial_command(struct sps30_state *state, unsigned char cmd,
 	return rsp_size;
 }
 
-static ssize_t sps30_serial_receive_buf(struct serdev_device *serdev,
-					const u8 *buf, size_t size)
+static size_t sps30_serial_receive_buf(struct serdev_device *serdev,
+				       const u8 *buf, size_t size)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(&serdev->dev);
 	struct sps30_serial_priv *priv;
diff --git a/drivers/iio/imu/bno055/bno055_ser_core.c b/drivers/iio/imu/bno055/bno055_ser_core.c
index 5677bdf4f846..694ff14a3aa2 100644
--- a/drivers/iio/imu/bno055/bno055_ser_core.c
+++ b/drivers/iio/imu/bno055/bno055_ser_core.c
@@ -378,8 +378,8 @@ static void bno055_ser_handle_rx(struct bno055_ser_priv *priv, int status)
  * Also, we assume to RX one pkt per time (i.e. the HW doesn't send anything
  * unless we require to AND we don't queue more than one request per time).
  */
-static ssize_t bno055_ser_receive_buf(struct serdev_device *serdev,
-				      const u8 *buf, size_t size)
+static size_t bno055_ser_receive_buf(struct serdev_device *serdev,
+				     const u8 *buf, size_t size)
 {
 	int status;
 	struct bno055_ser_priv *priv = serdev_device_get_drvdata(serdev);
diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c
index 6ff84b2600c5..62a6613fb070 100644
--- a/drivers/mfd/rave-sp.c
+++ b/drivers/mfd/rave-sp.c
@@ -471,8 +471,8 @@ static void rave_sp_receive_frame(struct rave_sp *sp,
 		rave_sp_receive_reply(sp, data, length);
 }
 
-static ssize_t rave_sp_receive_buf(struct serdev_device *serdev,
-				   const u8 *buf, size_t size)
+static size_t rave_sp_receive_buf(struct serdev_device *serdev,
+				  const u8 *buf, size_t size)
 {
 	struct device *dev = &serdev->dev;
 	struct rave_sp *sp = dev_get_drvdata(dev);
diff --git a/drivers/net/ethernet/qualcomm/qca_uart.c b/drivers/net/ethernet/qualcomm/qca_uart.c
index 223321897b96..20f50bde82ac 100644
--- a/drivers/net/ethernet/qualcomm/qca_uart.c
+++ b/drivers/net/ethernet/qualcomm/qca_uart.c
@@ -58,7 +58,7 @@ struct qcauart {
 	unsigned char *tx_buffer;
 };
 
-static ssize_t
+static size_t
 qca_tty_receive(struct serdev_device *serdev, const u8 *data, size_t count)
 {
 	struct qcauart *qca = serdev_device_get_drvdata(serdev);
diff --git a/drivers/nfc/pn533/uart.c b/drivers/nfc/pn533/uart.c
index 2eb5978bd79e..cfbbe0713317 100644
--- a/drivers/nfc/pn533/uart.c
+++ b/drivers/nfc/pn533/uart.c
@@ -203,8 +203,8 @@ static int pn532_uart_rx_is_frame(struct sk_buff *skb)
 	return 0;
 }
 
-static ssize_t pn532_receive_buf(struct serdev_device *serdev,
-				 const u8 *data, size_t count)
+static size_t pn532_receive_buf(struct serdev_device *serdev,
+				const u8 *data, size_t count)
 {
 	struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev);
 	size_t i;
diff --git a/drivers/nfc/s3fwrn5/uart.c b/drivers/nfc/s3fwrn5/uart.c
index 456d3947116c..9c09c10c2a46 100644
--- a/drivers/nfc/s3fwrn5/uart.c
+++ b/drivers/nfc/s3fwrn5/uart.c
@@ -51,8 +51,8 @@ static const struct s3fwrn5_phy_ops uart_phy_ops = {
 	.write = s3fwrn82_uart_write,
 };
 
-static ssize_t s3fwrn82_uart_read(struct serdev_device *serdev,
-				  const u8 *data, size_t count)
+static size_t s3fwrn82_uart_read(struct serdev_device *serdev,
+				 const u8 *data, size_t count)
 {
 	struct s3fwrn82_uart_phy *phy = serdev_device_get_drvdata(serdev);
 	size_t i;
diff --git a/drivers/platform/chrome/cros_ec_uart.c b/drivers/platform/chrome/cros_ec_uart.c
index 68d80559fddc..8ea867c2a01a 100644
--- a/drivers/platform/chrome/cros_ec_uart.c
+++ b/drivers/platform/chrome/cros_ec_uart.c
@@ -81,8 +81,8 @@ struct cros_ec_uart {
 	struct response_info response;
 };
 
-static ssize_t cros_ec_uart_rx_bytes(struct serdev_device *serdev,
-				     const u8 *data, size_t count)
+static size_t cros_ec_uart_rx_bytes(struct serdev_device *serdev,
+				    const u8 *data, size_t count)
 {
 	struct ec_host_response *host_response;
 	struct cros_ec_device *ec_dev = serdev_device_get_drvdata(serdev);
diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
index 9591a28bc38a..ba550eaa06fc 100644
--- a/drivers/platform/surface/aggregator/core.c
+++ b/drivers/platform/surface/aggregator/core.c
@@ -227,8 +227,8 @@ EXPORT_SYMBOL_GPL(ssam_client_bind);
 
 /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */
 
-static ssize_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf,
-				size_t n)
+static size_t ssam_receive_buf(struct serdev_device *dev, const u8 *buf,
+			       size_t n)
 {
 	struct ssam_controller *ctrl;
 	int ret;
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index e94e090cf0a1..3d7ae7fa5018 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -27,19 +27,17 @@ static size_t ttyport_receive_buf(struct tty_port *port, const u8 *cp,
 {
 	struct serdev_controller *ctrl = port->client_data;
 	struct serport *serport = serdev_controller_get_drvdata(ctrl);
-	int ret;
+	size_t ret;
 
 	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
 		return 0;
 
 	ret = serdev_controller_receive_buf(ctrl, cp, count);
 
-	dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count,
-				"receive_buf returns %d (count = %zu)\n",
+	dev_WARN_ONCE(&ctrl->dev, ret > count,
+				"receive_buf returns %zu (count = %zu)\n",
 				ret, count);
-	if (ret < 0)
-		return 0;
-	else if (ret > count)
+	if (ret > count)
 		return count;
 
 	return ret;
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 3fab88ba265e..ff78efc1f60d 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -27,7 +27,7 @@ struct serdev_device;
  *			not sleep.
  */
 struct serdev_device_ops {
-	ssize_t (*receive_buf)(struct serdev_device *, const u8 *, size_t);
+	size_t (*receive_buf)(struct serdev_device *, const u8 *, size_t);
 	void (*write_wakeup)(struct serdev_device *);
 };
 
@@ -185,9 +185,9 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl
 	serdev->ops->write_wakeup(serdev);
 }
 
-static inline ssize_t serdev_controller_receive_buf(struct serdev_controller *ctrl,
-						    const u8 *data,
-						    size_t count)
+static inline size_t serdev_controller_receive_buf(struct serdev_controller *ctrl,
+						   const u8 *data,
+						   size_t count)
 {
 	struct serdev_device *serdev = ctrl->serdev;
 
diff --git a/sound/drivers/serial-generic.c b/sound/drivers/serial-generic.c
index d6e5aafd697c..36409a56c675 100644
--- a/sound/drivers/serial-generic.c
+++ b/sound/drivers/serial-generic.c
@@ -100,8 +100,8 @@ static void snd_serial_generic_write_wakeup(struct serdev_device *serdev)
 	snd_serial_generic_tx_wakeup(drvdata);
 }
 
-static ssize_t snd_serial_generic_receive_buf(struct serdev_device *serdev,
-					      const u8 *buf, size_t count)
+static size_t snd_serial_generic_receive_buf(struct serdev_device *serdev,
+					     const u8 *buf, size_t count)
 {
 	int ret;
 	struct snd_serial_generic *drvdata = serdev_device_get_drvdata(serdev);
-- 
2.39.2
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