Re: [PATCH] net: ravb: Fix dma_addr_t truncation in error case

[Florian Fainelli]

On 1/12/2024 8:22 PM, Nikita Yushchenko wrote:
> In ravb_start_xmit(), ravb driver uses u32 variable to store result of
> dma_map_single() call. Since ravb hardware has 32-bit address fields in
> descriptors, this works properly when mapping is successful - it is
> platform's job to provide mapping addresses that fit into hardware
> limitations.
>
> However, in failure case dma_map_single() returns DMA_MAPPING_ERROR
> constant that is 64-bit when dma_addr_t is 64-bit. Storing this constant
> in u32 leads to truncation, and further call to dma_mapping_error()
> fails to notice the error.
>
> Fix that by storing result of dma_map_single() in a dma_addr_t
> variable.
>
> Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
> Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>

Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>

Nit: since this is a bug fix you should prefix your patches with "[PATCH 
net]", see:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/maintainer-netdev.rst#n62
--
Florian