Firmware requests 2 segments at first. The first segment is of 6799360 whose allocation fails due to dma remapping not available. The success is returned to firmware. Then firmware asks for 22 smaller segments instead of 2 big ones. Those get allocated successfully. At suspend/ hibernation time, these segments aren't freed as they will be reused by firmware after resuming. After resume the firmware asks for 2 segments again with first segment of 6799360 and vaddr is not NULL. We compare the type and size with previous type and size to know if it can be reused or not. Unfortunately, we detect that it cannot be reuses and this first smaller segment is freed. Then we continue to allocate 6799360 size memory from dma which fails and we call ath11k_qmi_free_target_mem_chunk() which frees the second smaller segment as well. Later success is returned to firmware which asks for 22 smaller segments again. But as we had freed 2 segments already, we'll allocate the first 2 new smaller segments again and reuse the remaining 20. Hence we aren't reusing the all 22 small segments, but only 20. This patch is correcting the skip logic when vaddr is set, but size/type don't match. In this case, we should use the same skip and success logic as used when dma_alloc_coherent fails without freeing the memory area. We had got reports that memory allocation in this function failed at resume [1] which made us debug why the reuse logic is wrong. Those failures weren't because of the bigger chunk allocation failure as they are skipped. Rather these failures were because of smaller chunk allocation failures. This issue is in the kernel side as because of memory pressure or fragmentation, the dma memory allocation fails. This patch fixes freeing and allocation of 2 smaller chunks. Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6 [1] https://lore.kernel.org/all/b30bc7f6-845d-4f9d-967e-c04a2b5f13f5@xxxxxxxxxxxxx Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx> --- Changes since v1: - Update description Fixes: 5962f370ce41 ("ath11k: Reuse the available memory after firmware reload") I think we should keep fixes tag as ^ claimed that its adding reuse support. But it left a bug in reuse which we are fixing. Feel free to add it or leave it as it is. --- drivers/net/wireless/ath/ath11k/qmi.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/ath/ath11k/qmi.c b/drivers/net/wireless/ath/ath11k/qmi.c index 47b9d4126d3a9..3c26f4dcf5d29 100644 --- a/drivers/net/wireless/ath/ath11k/qmi.c +++ b/drivers/net/wireless/ath/ath11k/qmi.c @@ -1990,8 +1990,16 @@ static int ath11k_qmi_alloc_target_mem_chunk(struct ath11k_base *ab) */ if (chunk->vaddr) { if (chunk->prev_type == chunk->type && - chunk->prev_size == chunk->size) + chunk->prev_size == chunk->size) { continue; + } else if (ab->qmi.mem_seg_count <= ATH11K_QMI_FW_MEM_REQ_SEGMENT_CNT) { + ath11k_dbg(ab, ATH11K_DBG_QMI, + "size/type mismatch (current %d %u) (prev %d %u), try later with small size\n", + chunk->size, chunk->type, + chunk->prev_size, chunk->prev_type); + ab->qmi.target_mem_delayed = true; + return 0; + } /* cannot reuse the existing chunk */ dma_free_coherent(ab->dev, chunk->prev_size, -- 2.43.0
