Re: [PATCH v7 0/3] staging: iio: adc: ad7816: Fix SPI operations race condition and DMA safety

[Joshua Crofts <joshua.crofts1@gmail.com>]

On Tue, 15 Sep 2026 10:59:36 +0300
Abdelnasser Hussein <abdelnasserhussein11@gmail.com> wrote:

> This series addresses separate issues in the ad7816 driver regarding
> race conditions and DMA safety across all SPI operations.
> 
> Changes in v7:
> 
>     Patch 2: Moved the mutex to the top of the ad7816_chip_info struct
>     (right after the pointers) to prevent struct padding/holes, as
>     pointed out by Andy Shevchenko. Also expanded the mutex to serialize
>     ad7816_spi_write() to prevent race conditions.
> 
>     Patch 3: Dropped the dedicated rx_buf. Switched all spi_write() and
>     spi_read() calls to use spi_write_then_read(..., NULL, 0) to safely
>     handle DMA using an internal bounce buffer, avoiding cacheline sharing,
>     as guided by Jonathan Cameron.
> 
> Changes in v6:
> 
>     Separated the alphabetical sorting of include headers into a dedicated
>     precursor patch (Patch 1).
> 
>     Kept the mutex addition strictly focused on serializing the read
>     operations without modifying the sizeof() argument (Patch 2).
> 
>     Moved the sizeof() argument fix to the DMA-safe buffer patch where
>     it logically belongs (Patch 3).
> 
> Changes in v5:
> 
>     Split the changes into separate patches for bisectability.
> 
>     Replaced stack buffer with a dedicated rx_buf aligned with
>     IIO_DMA_MINALIGN.
> 
> Abdelnasser Hussein (3):
>   staging: iio: adc: ad7816: Sort headers alphabetically
>   staging: iio: adc: ad7816: Serialize SPI operations
>   staging: iio: adc: ad7816: Fix DMA safety issues in SPI transfers
> 
>  drivers/staging/iio/adc/ad7816.c | 29 ++++++++++++++++++++---------
>  1 file changed, 20 insertions(+), 9 deletions(-)
> 

For the whole series:

Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>

-- 
Kind regards,
Joshua Crofts