Re: [PATCH v3] hv_netvsc: Allocate rx indirection table size dynamically

[Praveen Kumar]

On 5/26/2023 11:32 AM, Shradha Gupta wrote:
> Allocate the size of rx indirection table dynamically in netvsc
> from the value of size provided by OID_GEN_RECEIVE_SCALE_CAPABILITIES
> query instead of using a constant value of ITAB_NUM.
> 
> Signed-off-by: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>
> Tested-on: Ubuntu22 (azure VM, SKU size: Standard_F72s_v2)
> Testcases:
> 1. ethtool -x eth0 output
> 2. LISA testcase:PERF-NETWORK-TCP-THROUGHPUT-MULTICONNECTION-NTTTCP-Synthetic
> 3. LISA testcase:PERF-NETWORK-TCP-THROUGHPUT-MULTICONNECTION-NTTTCP-SRIOV
> 
> ---
> Changes in v3:
>  * Changed the data type of rx_table_sz to u32
>  * Moved the rx indirection table free to rndis_filter_device_remove()
>  * Device add will fail with error if not enough memory is available
>  * Changed kzmalloc to kcalloc as suggested in checkpatch script
>  * Removed redundant log if memory allocation failed.
> ---
>  drivers/net/hyperv/hyperv_net.h   |  5 ++++-
>  drivers/net/hyperv/netvsc_drv.c   | 10 ++++++----
>  drivers/net/hyperv/rndis_filter.c | 27 +++++++++++++++++++++++----
>  3 files changed, 33 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index dd5919ec408b..c40868f287a9 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -74,6 +74,7 @@ struct ndis_recv_scale_cap { /* NDIS_RECEIVE_SCALE_CAPABILITIES */
>  #define NDIS_RSS_HASH_SECRET_KEY_MAX_SIZE_REVISION_2   40
>  
>  #define ITAB_NUM 128
> +#define ITAB_NUM_MAX 256
>  
>  struct ndis_recv_scale_param { /* NDIS_RECEIVE_SCALE_PARAMETERS */
>  	struct ndis_obj_header hdr;
> @@ -1034,7 +1035,9 @@ struct net_device_context {
>  
>  	u32 tx_table[VRSS_SEND_TAB_SIZE];
>  
> -	u16 rx_table[ITAB_NUM];
> +	u16 *rx_table;
> +
> +	u32 rx_table_sz;
>  
>  	/* Ethtool settings */
>  	u8 duplex;
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 0103ff914024..3ba3c8fb28a5 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -1747,7 +1747,9 @@ static u32 netvsc_get_rxfh_key_size(struct net_device *dev)
>  
>  static u32 netvsc_rss_indir_size(struct net_device *dev)
>  {
> -	return ITAB_NUM;
> +	struct net_device_context *ndc = netdev_priv(dev);
> +
> +	return ndc->rx_table_sz;
>  }
>  
>  static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
> @@ -1766,7 +1768,7 @@ static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
>  
>  	rndis_dev = ndev->extension;
>  	if (indir) {
> -		for (i = 0; i < ITAB_NUM; i++)
> +		for (i = 0; i < ndc->rx_table_sz; i++)
>  			indir[i] = ndc->rx_table[i];
>  	}
>  
> @@ -1792,11 +1794,11 @@ static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
>  
>  	rndis_dev = ndev->extension;
>  	if (indir) {
> -		for (i = 0; i < ITAB_NUM; i++)
> +		for (i = 0; i < ndc->rx_table_sz; i++)
>  			if (indir[i] >= ndev->num_chn)
>  				return -EINVAL;
>  
> -		for (i = 0; i < ITAB_NUM; i++)
> +		for (i = 0; i < ndc->rx_table_sz; i++)
>  			ndc->rx_table[i] = indir[i];
>  	}
>  
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index eea777ec2541..dc7b9b326690 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -21,6 +21,7 @@
>  #include <linux/rtnetlink.h>
>  #include <linux/ucs2_string.h>
>  #include <linux/string.h>
> +#include <linux/slab.h>
>  
>  #include "hyperv_net.h"
>  #include "netvsc_trace.h"
> @@ -927,7 +928,7 @@ static int rndis_set_rss_param_msg(struct rndis_device *rdev,
>  	struct rndis_set_request *set;
>  	struct rndis_set_complete *set_complete;
>  	u32 extlen = sizeof(struct ndis_recv_scale_param) +
> -		     4 * ITAB_NUM + NETVSC_HASH_KEYLEN;
> +		     4 * ndc->rx_table_sz + NETVSC_HASH_KEYLEN;
>  	struct ndis_recv_scale_param *rssp;
>  	u32 *itab;
>  	u8 *keyp;
> @@ -953,7 +954,7 @@ static int rndis_set_rss_param_msg(struct rndis_device *rdev,
>  	rssp->hashinfo = NDIS_HASH_FUNC_TOEPLITZ | NDIS_HASH_IPV4 |
>  			 NDIS_HASH_TCP_IPV4 | NDIS_HASH_IPV6 |
>  			 NDIS_HASH_TCP_IPV6;
> -	rssp->indirect_tabsize = 4*ITAB_NUM;
> +	rssp->indirect_tabsize = 4 * ndc->rx_table_sz;
>  	rssp->indirect_taboffset = sizeof(struct ndis_recv_scale_param);
>  	rssp->hashkey_size = NETVSC_HASH_KEYLEN;
>  	rssp->hashkey_offset = rssp->indirect_taboffset +
> @@ -961,7 +962,7 @@ static int rndis_set_rss_param_msg(struct rndis_device *rdev,
>  
>  	/* Set indirection table entries */
>  	itab = (u32 *)(rssp + 1);
> -	for (i = 0; i < ITAB_NUM; i++)
> +	for (i = 0; i < ndc->rx_table_sz; i++)
>  		itab[i] = ndc->rx_table[i];
>  
>  	/* Set hask key values */
> @@ -1548,6 +1549,17 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
>  	if (ret || rsscap.num_recv_que < 2)
>  		goto out;
>  
> +	if (rsscap.num_indirect_tabent &&
> +	    rsscap.num_indirect_tabent <= ITAB_NUM_MAX)
> +		ndc->rx_table_sz = rsscap.num_indirect_tabent;
> +	else
> +		ndc->rx_table_sz = ITAB_NUM;
> +
> +	ndc->rx_table = kcalloc(ndc->rx_table_sz, sizeof(u16),
> +				GFP_KERNEL);
> +	if (!ndc->rx_table)
> +		goto err_dev_remv;
> +
>  	/* This guarantees that num_possible_rss_qs <= num_online_cpus */
>  	num_possible_rss_qs = min_t(u32, num_online_cpus(),
>  				    rsscap.num_recv_que);
> @@ -1558,7 +1570,7 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
>  	net_device->num_chn = min(net_device->max_chn, device_info->num_chn);
>  
>  	if (!netif_is_rxfh_configured(net)) {
> -		for (i = 0; i < ITAB_NUM; i++)
> +		for (i = 0; i < ndc->rx_table_sz; i++)
>  			ndc->rx_table[i] = ethtool_rxfh_indir_default(
>  						i, net_device->num_chn);
>  	}
> @@ -1596,11 +1608,18 @@ void rndis_filter_device_remove(struct hv_device *dev,
>  				struct netvsc_device *net_dev)
>  {
>  	struct rndis_device *rndis_dev = net_dev->extension;
> +	struct net_device *net = hv_get_drvdata(dev);
> +	struct net_device_context *ndc = netdev_priv(net);
>  
>  	/* Halt and release the rndis device */
>  	rndis_filter_halt_device(net_dev, rndis_dev);
>  
>  	netvsc_device_remove(dev);

Shouldn't the netvsc_device_remove be called post table cleanup ? or better, the cleanup should happen as part of netvsc_device_remove operation ? This looks a bug to me as with remove operation, we already cleaned up the device and the association between context and device is removed.
> +
> +	ndc->rx_table_sz = 0;
> +	kfree(ndc->rx_table);
> +	ndc->rx_table = NULL;
> +
>  }
>  
>  int rndis_filter_open(struct netvsc_device *nvdev)