Wrong place for rxbaddr/txbaddr to be in struct ath12k_spt_info

[Karthikeyan Periyasamy]

On 8/28/2024 7:34 PM, Nicolas Escande wrote:
> Hi there,
> 
> Looking into a problem we have on an ath12k platform at work with a colleague,
> I stumbled upon something that seems weird.
> 
> The interresting parts of dh.h:
> 
> struct ath12k_spt_info {
> 	dma_addr_t paddr;
> 	u64 *vaddr;
> 	struct ath12k_rx_desc_info *rxbaddr[ATH12K_NUM_RX_SPT_PAGES];
> 	struct ath12k_tx_desc_info *txbaddr[ATH12K_NUM_TX_SPT_PAGES];
> };
> 
> ...
> 
> struct ath12k_dp {
> 	struct ath12k_base *ab;
> 	...
> 	struct ath12k_spt_info *spt_info;
> 	u32 num_spt_pages;
> 	u32 rx_ppt_base;
> 	...
> };
> 
> In dp.c we have ath12k_dp_cc_desc_init that allocs arrays of ath12k_rx_desc_info
> stores the addresses of the individual desc in each of the spt entries using
> ath12k_dp_cc_get_desc_addr_ptr(), but we also save the address of the whole
> array for later cleanup by dp->spt_info->rxbaddr[i] = &rx_descs[0];
> 
> Surely this is wrong, with the current code we always use the first element of
> dp->spt_info to store all the descriptors arrays. And the same goes for txbaddr.
> I mean it works, but we loose memory for no purpose & make this part of the
> driver harder to understand.
> 
> It should be something like:
> 
> diff --git a/drivers/net/wireless/ath/ath12k/dp.c b/drivers/net/wireless/ath/ath12k/dp.c
> index 61aa78d8bd8c..ecd3b5c76d26 100644
> --- a/drivers/net/wireless/ath/ath12k/dp.c
> +++ b/drivers/net/wireless/ath/ath12k/dp.c
> @@ -1162,7 +1162,7 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
>   	spin_lock_bh(&dp->rx_desc_lock);
>   
>   	for (i = 0; i < ATH12K_NUM_RX_SPT_PAGES; i++) {
> -		desc_info = dp->spt_info->rxbaddr[i];
> +		desc_info = dp->rxbaddr[i];
>   
>   		for (j = 0; j < ATH12K_MAX_SPT_ENTRIES; j++) {
>   			if (!desc_info[j].in_use) {
> @@ -1181,11 +1181,11 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
>   	}
>   
>   	for (i = 0; i < ATH12K_NUM_RX_SPT_PAGES; i++) {
> -		if (!dp->spt_info->rxbaddr[i])
> +		if (!dp->rxbaddr[i])
>   			continue;
>   
> -		kfree(dp->spt_info->rxbaddr[i]);
> -		dp->spt_info->rxbaddr[i] = NULL;
> +		kfree(dp->rxbaddr[i]);
> +		dp->rxbaddr[i] = NULL;
>   	}
>   
>   	spin_unlock_bh(&dp->rx_desc_lock);
> @@ -1220,11 +1220,11 @@ static void ath12k_dp_cc_cleanup(struct ath12k_base *ab)
>   
>   		for (i = 0; i < ATH12K_TX_SPT_PAGES_PER_POOL; i++) {
>   			tx_spt_page = i + pool_id * ATH12K_TX_SPT_PAGES_PER_POOL;
> -			if (!dp->spt_info->txbaddr[tx_spt_page])
> +			if (!dp->txbaddr[tx_spt_page])
>   				continue;
>   
> -			kfree(dp->spt_info->txbaddr[tx_spt_page]);
> -			dp->spt_info->txbaddr[tx_spt_page] = NULL;
> +			kfree(dp->txbaddr[tx_spt_page]);
> +			dp->txbaddr[tx_spt_page] = NULL;
>   		}
>   
>   		spin_unlock_bh(&dp->tx_desc_lock[pool_id]);
> @@ -1415,7 +1415,7 @@ static int ath12k_dp_cc_desc_init(struct ath12k_base *ab)
>   
>   		ppt_idx = ATH12K_RX_SPT_PAGE_OFFSET + i;
>   		cookie_ppt_idx = dp->rx_ppt_base + ppt_idx;
> -		dp->spt_info->rxbaddr[i] = &rx_descs[0];
> +		dp->rxbaddr[i] = &rx_descs[0];
>   
>   		for (j = 0; j < ATH12K_MAX_SPT_ENTRIES; j++) {
>   			rx_descs[j].cookie = ath12k_dp_cc_cookie_gen(cookie_ppt_idx, j);
> @@ -1445,7 +1445,7 @@ static int ath12k_dp_cc_desc_init(struct ath12k_base *ab)
>   			tx_spt_page = i + pool_id * ATH12K_TX_SPT_PAGES_PER_POOL;
>   			ppt_idx = ATH12K_TX_SPT_PAGE_OFFSET + tx_spt_page;
>   
> -			dp->spt_info->txbaddr[tx_spt_page] = &tx_descs[0];
> +			dp->txbaddr[tx_spt_page] = &tx_descs[0];
>   
>   			for (j = 0; j < ATH12K_MAX_SPT_ENTRIES; j++) {
>   				tx_descs[j].desc_id = ath12k_dp_cc_cookie_gen(ppt_idx, j);
> diff --git a/drivers/net/wireless/ath/ath12k/dp.h b/drivers/net/wireless/ath/ath12k/dp.h
> index b77497c14ac4..28c8bf22810c 100644
> --- a/drivers/net/wireless/ath/ath12k/dp.h
> +++ b/drivers/net/wireless/ath/ath12k/dp.h
> @@ -300,8 +300,6 @@ struct ath12k_tx_desc_info {
>   struct ath12k_spt_info {
>   	dma_addr_t paddr;
>   	u64 *vaddr;
> -	struct ath12k_rx_desc_info *rxbaddr[ATH12K_NUM_RX_SPT_PAGES];
> -	struct ath12k_tx_desc_info *txbaddr[ATH12K_NUM_TX_SPT_PAGES];
>   };
>   
>   struct ath12k_reo_queue_ref {
> @@ -352,6 +350,8 @@ struct ath12k_dp {
>   	struct ath12k_spt_info *spt_info;
>   	u32 num_spt_pages;
>   	u32 rx_ppt_base;
> +	struct ath12k_rx_desc_info *rxbaddr[ATH12K_NUM_RX_SPT_PAGES];
> +	struct ath12k_tx_desc_info *txbaddr[ATH12K_NUM_TX_SPT_PAGES];
>   	struct list_head rx_desc_free_list;
>   	/* protects the free desc list */
>   	spinlock_t rx_desc_lock;
> 
> Right ?
> 

Yes, we always use the first element of dp->spt_info to store all the 
descriptors arrays.

-- 
Karthikeyan Periyasamy
--
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