This is a note to let you know that I've just added the patch titled
tty: serial: fsl_lpuart: adjust buffer length to the intended size
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tty-serial-fsl_lpuart-adjust-buffer-length-to-the-in.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 148518db9ff42e114c561f8d0bd5c82ae248715c
Author: Shenwei Wang <shenwei.wang@xxxxxxx>
Date: Mon Apr 10 14:55:55 2023 -0500
tty: serial: fsl_lpuart: adjust buffer length to the intended size
[ Upstream commit f73fd750552524b06b5d77ebfdd106ccc8fcac61 ]
Based on the fls function definition provided below, we should not
subtract 1 to obtain the correct buffer length:
fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx>
Link: https://lore.kernel.org/r/20230410195555.1003900-1-shenwei.wang@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 6ea1d23623e51..dbfec943071d6 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -994,7 +994,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
* 10ms at any baud rate.
*/
sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / bits / 1000) * 2;
- sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
+ sport->rx_dma_rng_buf_len = (1 << fls(sport->rx_dma_rng_buf_len));
if (sport->rx_dma_rng_buf_len < 16)
sport->rx_dma_rng_buf_len = 16;
