Re: [PATCH] ath10k: fix invalid dma_addr_t token assignment

On 14/10/2021 04:51, Arnd Bergmann wrote:

From: Arnd Bergmann <arnd@arndb.de>

Using a kernel pointer in place of a dma_addr_t token can
lead to undefined behavior if that makes it into cache
management functions. The compiler caught one such attempt
in a cast:

drivers/net/wireless/ath/ath10k/mac.c: In function 'ath10k_add_interface':
drivers/net/wireless/ath/ath10k/mac.c:5586:47: error: cast from
pointer to integer of different size [-Werror=pointer-to-int-cast]
 5586 |                         arvif->beacon_paddr =
(dma_addr_t)arvif->beacon_buf;
      |                                               ^

Looking through how this gets used down the way, I'm fairly
sure that beacon_paddr is never accessed again for ATH10K_DEV_TYPE_HL
devices, and if it was accessed, that would be a bug.

Change the assignment to use a known-invalid address token
instead, which avoids the warning and makes it easier to catch
bugs if it does end up getting used.

Fixes: e263bdab9c0e ("ath10k: high latency fixes for beacon buffer")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Fabio Estevam <redacted>