5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold johan+linaro@kernel.org
commit 6efa0df54022c6c9fd4d294b87622c7fcdc418c8 upstream.
Add the missing memory barrier to make sure that LMAC source ring descriptors are written before updating the head pointer to avoid passing stale data to the firmware on weakly ordered architectures like aarch64.
Note that non-LMAC rings use MMIO write accessors which have the required write memory barrier.
Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") Cc: stable@vger.kernel.org # 5.6 Signed-off-by: Johan Hovold johan+linaro@kernel.org Reviewed-by: Baochen Qiang quic_bqiang@quicinc.com Link: https://patch.msgid.link/20250604143457.26032-5-johan+linaro@kernel.org Signed-off-by: Jeff Johnson jeff.johnson@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/ath/ath11k/hal.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/drivers/net/wireless/ath/ath11k/hal.c +++ b/drivers/net/wireless/ath/ath11k/hal.c @@ -797,7 +797,11 @@ void ath11k_hal_srng_access_end(struct a if (srng->ring_dir == HAL_SRNG_DIR_SRC) { srng->u.src_ring.last_tp = *(volatile u32 *)srng->u.src_ring.tp_addr; - *srng->u.src_ring.hp_addr = srng->u.src_ring.hp; + /* Make sure descriptor is written before updating the + * head pointer. + */ + dma_wmb(); + WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp); } else { srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr; *srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp; @@ -806,6 +810,10 @@ void ath11k_hal_srng_access_end(struct a if (srng->ring_dir == HAL_SRNG_DIR_SRC) { srng->u.src_ring.last_tp = *(volatile u32 *)srng->u.src_ring.tp_addr; + /* Assume implementation use an MMIO write accessor + * which has the required wmb() so that the descriptor + * is written before the updating the head pointer. + */ ath11k_hif_write32(ab, (unsigned long)srng->u.src_ring.hp_addr - (unsigned long)ab->mem,