Re: [PATCH v2] iio: imu: st_lsm6dsx: fix possible lockup during FIFO read

[Lorenzo Bianconi <lorenzo@kernel.org>]

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I guess it was v3 in this case :)

Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>

Regards,
Lorenzo

> Prevent st_lsm6dsx_read_fifo and st_lsm6dsx_read_tagged_fifo functions
> from falling in an infinite loop in case pattern_len is equal to zero and
> the device FIFO is not empty.
> 
> Fixes: 290a6ce11d93 ("iio: imu: add support to lsm6dsx driver")
> Fixes: 801a6e0af0c6 ("iio: imu: st_lsm6dsx: add support to LSM6DSO")
> Signed-off-by: Silvano Seva <s.seva@4sigma.it>
> ---
> 
> Changes since v1:
> * st_lsm6dsx_read_fifo: moved check for zero pattern_len before fifo_len assignment
> * st_lsm6dsx_read_fifo: dropped check for zero fifo_len
> * added Fixes tags in commit message
> 
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> index 0a7cd8c1aa33..8a9d2593576a 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> @@ -392,6 +392,9 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
>  	if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
>  		return 0;
>  
> +	if (!pattern_len)
> +		pattern_len = ST_LSM6DSX_SAMPLE_SIZE;
> +
>  	fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
>  		   ST_LSM6DSX_CHAN_SIZE;
>  	fifo_len = (fifo_len / pattern_len) * pattern_len;
> @@ -623,6 +626,9 @@ int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
>  	if (!fifo_len)
>  		return 0;
>  
> +	if (!pattern_len)
> +		pattern_len = ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
> +
>  	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
>  		err = st_lsm6dsx_read_block(hw,
>  					    ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
> -- 
> 2.48.1
> 

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