This is a note to let you know that I've just added the patch titled spi: dw: Fix wrong FIFO level setting for long xfers to the 5.10-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: spi-dw-fix-wrong-fifo-level-setting-for-long-xfers.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2a7736ed0c50f9f518e62b820c40d59d615acec2 Author: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> Date: Fri Jan 13 21:59:42 2023 +0300 spi: dw: Fix wrong FIFO level setting for long xfers [ Upstream commit c63b8fd14a7db719f8252038a790638728c4eb66 ] Due to using the u16 type in the min_t() macros the SPI transfer length will be cast to word before participating in the conditional statement implied by the macro. Thus if the transfer length is greater than 64KB the Tx/Rx FIFO threshold level value will be determined by the leftover of the truncated after the type-case length. In the worst case it will cause the dramatical performance drop due to the "Tx FIFO Empty" or "Rx FIFO Full" interrupts triggered on each xfer word sent/received to/from the bus. The problem can be easily fixed by specifying the unsigned int type in the min_t() macros thus preventing the possible data loss. Fixes: ea11370fffdf ("spi: dw: get TX level without an additional variable") Reported-by: Sergey Nazarov <Sergey.Nazarov@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230113185942.2516-1-Sergey.Semin@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index c33866f747dbe..aa116cee1fd8d 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -353,7 +353,7 @@ static void dw_spi_irq_setup(struct dw_spi *dws) * will be adjusted at the final stage of the IRQ-based SPI transfer * execution so not to lose the leftover of the incoming data. */ - level = min_t(u16, dws->fifo_len / 2, dws->tx_len); + level = min_t(unsigned int, dws->fifo_len / 2, dws->tx_len); dw_writel(dws, DW_SPI_TXFTLR, level); dw_writel(dws, DW_SPI_RXFTLR, level - 1);