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

[Shradha Gupta <shradhagupta@linux.microsoft.com>]

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@linux.microsoft.com>
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);
+
+	ndc->rx_table_sz = 0;
+	kfree(ndc->rx_table);
+	ndc->rx_table = NULL;
+
 }
 
 int rndis_filter_open(struct netvsc_device *nvdev)
-- 
2.34.1