[PATCH v2 0/3] Bluetooth: fix recv_buf() return value

[PATCH v2 0/3] Bluetooth: fix recv_buf() return value

[Francesco Dolcini]

From: Francesco Dolcini <francesco.dolcini@toradex.com>

Serdev recv_buf() callback is supposed to return the amount of bytes consumed, therefore an int in between 0 and count.

Do not return negative number in case of issue, just print an error and return count. This fixes a WARN in ttyport_receive_buf().

In addition to that a small cleanup patch is added on btnxpuart to remove a useless assignment.

v2:
 - improved commit messages

Francesco Dolcini (3):
  Bluetooth: btnxpuart: fix recv_buf() return value
  Bluetooth: btmtkuart: fix recv_buf() return value
  Bluetooth: btnxpuart: remove useless assignment

 drivers/bluetooth/btmtkuart.c | 11 +++--------
 drivers/bluetooth/btnxpuart.c |  8 +++-----
 2 files changed, 6 insertions(+), 13 deletions(-)

-- 
2.25.1

[PATCH v2 1/3] Bluetooth: btnxpuart: fix recv_buf() return value

[Francesco Dolcini]

From: Francesco Dolcini <francesco.dolcini@toradex.com>

Serdev recv_buf() callback is supposed to return the amount of bytes
consumed, therefore an int in between 0 and count.

Do not return a negative number in case of issue, just print an error
and return count. Before this change, in case of error, the returned
negative number was internally converted to 0 in ttyport_receive_buf,
now when the receive buffer is corrupted we return the size of the whole
received data (`count`). This should allow for better recovery in case
receiver/transmitter get out of sync if some data is lost.

This fixes a WARN in ttyport_receive_buf().

  Bluetooth: hci0: Frame reassembly failed (-84)
  ------------[ cut here ]------------
  serial serial0: receive_buf returns -84 (count = 6)
  WARNING: CPU: 0 PID: 37 at drivers/tty/serdev/serdev-ttyport.c:37 ttyport_receive_buf+0xd8/0xf8
  Modules linked in: mwifiex_sdio(+) ...
  CPU: 0 PID: 37 Comm: kworker/u4:2 Not tainted 6.7.0-rc2-00147-gf1a09972a45a #1
  Hardware name: Toradex Verdin AM62 WB on Verdin Development Board (DT)
  Workqueue: events_unbound flush_to_ldisc
  pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  pc : ttyport_receive_buf+0xd8/0xf8
  lr : ttyport_receive_buf+0xd8/0xf8
...
  Call trace:
   ttyport_receive_buf+0xd8/0xf8
   flush_to_ldisc+0xbc/0x1a4
   process_scheduled_works+0x16c/0x28c

Closes: https://lore.kernel.org/all/ZWEIhcUXfutb5SY6@francesco-nb.int.toradex.com/
Fixes: 689ca16e5232 ("Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
v2:
 - improve commit message
---
 drivers/bluetooth/btnxpuart.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index b7e66b7ac570..951fe3014a3f 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -1276,11 +1276,10 @@ static int btnxpuart_receive_buf(struct serdev_device *serdev, const u8 *data,
 	if (IS_ERR(nxpdev->rx_skb)) {
 		int err = PTR_ERR(nxpdev->rx_skb);
 		/* Safe to ignore out-of-sync bootloader signatures */
-		if (is_fw_downloading(nxpdev))
-			return count;
-		bt_dev_err(nxpdev->hdev, "Frame reassembly failed (%d)", err);
+		if (!is_fw_downloading(nxpdev))
+			bt_dev_err(nxpdev->hdev, "Frame reassembly failed (%d)", err);
 		nxpdev->rx_skb = NULL;
-		return err;
+		return count;
 	}
 	if (!is_fw_downloading(nxpdev))
 		nxpdev->hdev->stat.byte_rx += count;
-- 
2.25.1

[PATCH v2 2/3] Bluetooth: btmtkuart: fix recv_buf() return value

[Francesco Dolcini]

From: Francesco Dolcini <francesco.dolcini@toradex.com>

Serdev recv_buf() callback is supposed to return the amount of bytes
consumed, therefore an int in between 0 and count.

Do not return negative number in case of issue, just print an error and
return count. This fixes a WARN in ttyport_receive_buf().

Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/
Fixes: 7237c4c9ec92 ("Bluetooth: mediatek: Add protocol support for MediaTek serial devices")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
 drivers/bluetooth/btmtkuart.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/bluetooth/btmtkuart.c b/drivers/bluetooth/btmtkuart.c
index 935feab815d9..203a000a84e3 100644
--- a/drivers/bluetooth/btmtkuart.c
+++ b/drivers/bluetooth/btmtkuart.c
@@ -336,7 +336,7 @@ mtk_stp_split(struct btmtkuart_dev *bdev, const unsigned char *data, int count,
 	return data;
 }
 
-static int btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
+static void btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	const unsigned char *p_left = data, *p_h4;
@@ -375,25 +375,20 @@ static int btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
 			bt_dev_err(bdev->hdev,
 				   "Frame reassembly failed (%d)", err);
 			bdev->rx_skb = NULL;
-			return err;
+			return;
 		}
 
 		sz_left -= sz_h4;
 		p_left += sz_h4;
 	}
-
-	return 0;
 }
 
 static int btmtkuart_receive_buf(struct serdev_device *serdev, const u8 *data,
 				 size_t count)
 {
 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
-	int err;
 
-	err = btmtkuart_recv(bdev->hdev, data, count);
-	if (err < 0)
-		return err;
+	btmtkuart_recv(bdev->hdev, data, count);
 
 	bdev->hdev->stat.byte_rx += count;
 
-- 
2.25.1

[PATCH v2 3/3] Bluetooth: btnxpuart: remove useless assignment

[Francesco Dolcini]

From: Francesco Dolcini <francesco.dolcini@toradex.com>

Remove useless assignment of rx_skb to NULL in case the skb is in error,
this is already done in h4_recv_buf() that is executed a few lines
before.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
 drivers/bluetooth/btnxpuart.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/bluetooth/btnxpuart.c b/drivers/bluetooth/btnxpuart.c
index 951fe3014a3f..b7c56be078f8 100644
--- a/drivers/bluetooth/btnxpuart.c
+++ b/drivers/bluetooth/btnxpuart.c
@@ -1278,7 +1278,6 @@ static int btnxpuart_receive_buf(struct serdev_device *serdev, const u8 *data,
 		/* Safe to ignore out-of-sync bootloader signatures */
 		if (!is_fw_downloading(nxpdev))
 			bt_dev_err(nxpdev->hdev, "Frame reassembly failed (%d)", err);
-		nxpdev->rx_skb = NULL;
 		return count;
 	}
 	if (!is_fw_downloading(nxpdev))
-- 
2.25.1

Re: [PATCH v2 0/3] Bluetooth: fix recv_buf() return value

[patchwork-bot+bluetooth]

Hello:

This series was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Mon, 11 Dec 2023 17:40:17 +0100 you wrote:
> From: Francesco Dolcini <francesco.dolcini@toradex.com>
> 
> Serdev recv_buf() callback is supposed to return the amount of bytes consumed, therefore an int in between 0 and count.
> 
> Do not return negative number in case of issue, just print an error and return count. This fixes a WARN in ttyport_receive_buf().
> 
> In addition to that a small cleanup patch is added on btnxpuart to remove a useless assignment.
> 
> [...]

Here is the summary with links:
  - [v2,1/3] Bluetooth: btnxpuart: fix recv_buf() return value
    https://git.kernel.org/bluetooth/bluetooth-next/c/7954bbcdd7ea
  - [v2,2/3] Bluetooth: btmtkuart: fix recv_buf() return value
    https://git.kernel.org/bluetooth/bluetooth-next/c/687d2de93b11
  - [v2,3/3] Bluetooth: btnxpuart: remove useless assignment
    https://git.kernel.org/bluetooth/bluetooth-next/c/99f188d71731

You are awesome, thank you!
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