diff --git a/Documentation/networking/pktgen.rst b/Documentation/networking/pktgen.rst
index 1225f0f63ff078b71cbd2abbb75e32204fe58bd9..c945218946e1d45633fa1d599545be64bcdac5da 100644
--- a/Documentation/networking/pktgen.rst
+++ b/Documentation/networking/pktgen.rst
@@ -178,6 +178,7 @@ Examples::
IPSEC # IPsec encapsulation (needs CONFIG_XFRM)
NODE_ALLOC # node specific memory allocation
NO_TIMESTAMP # disable timestamping
+ SHARED # enable shared SKB
pgset 'flag ![name]' Clear a flag to determine behaviour.
Note that you might need to use single quote in
interactive mode, so that your shell wouldn't expand
@@ -288,6 +289,16 @@ To avoid breaking existing testbed scripts for using AH type and tunnel mode,
you can use "pgset spi SPI_VALUE" to specify which transformation mode
to employ.
+Disable shared SKB
+==================
+By default, SKBs sent by pktgen are shared (user count > 1).
+To test with non-shared SKBs, remove the "SHARED" flag by simply setting::
+
+ pg_set "flag !SHARED"
+
+However, if the "clone_skb" or "burst" parameters are configured, the skb
+still needs to be held by pktgen for further access. Hence the skb must be
+shared.
Current commands and configuration options
==========================================
@@ -357,6 +368,7 @@ Current commands and configuration options
IPSEC
NODE_ALLOC
NO_TIMESTAMP
+ SHARED
spi (ipsec)
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 48306a101fd9f2408192e157357aad7fe6ef714b..5e865af82e5b8fcd74425e9ec201f5f55e53c106 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -200,6 +200,7 @@
pf(VID_RND) /* Random VLAN ID */ \
pf(SVID_RND) /* Random SVLAN ID */ \
pf(NODE) /* Node memory alloc*/ \
+ pf(SHARED) /* Shared SKB */ \
#define pf(flag) flag##_SHIFT,
enum pkt_flags {
@@ -1198,7 +1199,8 @@ static ssize_t pktgen_if_write(struct file *file,
((pkt_dev->xmit_mode == M_NETIF_RECEIVE) ||
!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))
return -ENOTSUPP;
- if (value > 0 && pkt_dev->n_imix_entries > 0)
+ if (value > 0 && (pkt_dev->n_imix_entries > 0 ||
+ !(pkt_dev->flags & F_SHARED)))
return -EINVAL;
i += len;
@@ -1257,6 +1259,10 @@ static ssize_t pktgen_if_write(struct file *file,
((pkt_dev->xmit_mode == M_START_XMIT) &&
(!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))))
return -ENOTSUPP;
+
+ if (value > 1 && !(pkt_dev->flags & F_SHARED))
+ return -EINVAL;
+
pkt_dev->burst = value < 1 ? 1 : value;
sprintf(pg_result, "OK: burst=%u", pkt_dev->burst);
return count;
@@ -1334,10 +1340,19 @@ static ssize_t pktgen_if_write(struct file *file,
flag = pktgen_read_flag(f, &disable);
if (flag) {
- if (disable)
+ if (disable) {
+ /* If "clone_skb", or "burst" parameters are
+ * configured, it means that the skb still
+ * needs to be referenced by the pktgen, so
+ * the skb must be shared.
+ */
+ if (flag == F_SHARED && (pkt_dev->clone_skb ||
+ pkt_dev->burst > 1))
+ return -EINVAL;
pkt_dev->flags &= ~flag;
- else
+ } else {
pkt_dev->flags |= flag;
+ }
sprintf(pg_result, "OK: flags=0x%x", pkt_dev->flags);
return count;
@@ -3446,12 +3461,24 @@ static void pktgen_wait_for_skb(struct pktgen_dev *pkt_dev)
static void pktgen_xmit(struct pktgen_dev *pkt_dev)
{
- unsigned int burst = READ_ONCE(pkt_dev->burst);
+ bool skb_shared = !!(READ_ONCE(pkt_dev->flags) & F_SHARED);
struct net_device *odev = pkt_dev->odev;
struct netdev_queue *txq;
+ unsigned int burst = 1;
struct sk_buff *skb;
+ int clone_skb = 0;
int ret;
+ /* If 'skb_shared' is false, the read of possible
+ * new values (if any) for 'burst' and 'clone_skb' will be skipped to
+ * prevent some concurrent changes from slipping in. And the stabilized
+ * config will be read in during the next run of pktgen_xmit.
+ */
+ if (skb_shared) {
+ burst = READ_ONCE(pkt_dev->burst);
+ clone_skb = READ_ONCE(pkt_dev->clone_skb);
+ }
+
/* If device is offline, then don't send */
if (unlikely(!netif_running(odev) || !netif_carrier_ok(odev))) {
pktgen_stop_device(pkt_dev);
@@ -3468,7 +3495,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
/* If no skb or clone count exhausted then get new one */
if (!pkt_dev->skb || (pkt_dev->last_ok &&
- ++pkt_dev->clone_count >= pkt_dev->clone_skb)) {
+ ++pkt_dev->clone_count >= clone_skb)) {
/* build a new pkt */
kfree_skb(pkt_dev->skb);
@@ -3489,7 +3516,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
if (pkt_dev->xmit_mode == M_NETIF_RECEIVE) {
skb = pkt_dev->skb;
skb->protocol = eth_type_trans(skb, skb->dev);
- refcount_add(burst, &skb->users);
+ if (skb_shared)
+ refcount_add(burst, &skb->users);
local_bh_disable();
do {
ret = netif_receive_skb(skb);
@@ -3497,6 +3525,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
pkt_dev->errors++;
pkt_dev->sofar++;
pkt_dev->seq_num++;
+ if (unlikely(!skb_shared)) {
+ pkt_dev->skb = NULL;
+ break;
+ }
if (refcount_read(&skb->users) != burst) {
/* skb was queued by rps/rfs or taps,
* so cannot reuse this skb
@@ -3515,9 +3547,14 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
goto out; /* Skips xmit_mode M_START_XMIT */
} else if (pkt_dev->xmit_mode == M_QUEUE_XMIT) {
local_bh_disable();
- refcount_inc(&pkt_dev->skb->users);
+ if (skb_shared)
+ refcount_inc(&pkt_dev->skb->users);
ret = dev_queue_xmit(pkt_dev->skb);
+
+ if (!skb_shared && dev_xmit_complete(ret))
+ pkt_dev->skb = NULL;
+
switch (ret) {
case NET_XMIT_SUCCESS:
pkt_dev->sofar++;
@@ -3555,11 +3592,15 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
pkt_dev->last_ok = 0;
goto unlock;
}
- refcount_add(burst, &pkt_dev->skb->users);
+ if (skb_shared)
+ refcount_add(burst, &pkt_dev->skb->users);
xmit_more:
ret = netdev_start_xmit(pkt_dev->skb, odev, txq, --burst > 0);
+ if (!skb_shared && dev_xmit_complete(ret))
+ pkt_dev->skb = NULL;
+
switch (ret) {
case NETDEV_TX_OK:
pkt_dev->last_ok = 1;
@@ -3581,7 +3622,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
fallthrough;
case NETDEV_TX_BUSY:
/* Retry it next time */
- refcount_dec(&(pkt_dev->skb->users));
+ if (skb_shared)
+ refcount_dec(&pkt_dev->skb->users);
pkt_dev->last_ok = 0;
}
if (unlikely(burst))
@@ -3594,7 +3636,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
/* If pkt_dev->count is zero, then run forever */
if ((pkt_dev->count != 0) && (pkt_dev->sofar >= pkt_dev->count)) {
- pktgen_wait_for_skb(pkt_dev);
+ if (pkt_dev->skb)
+ pktgen_wait_for_skb(pkt_dev);
/* Done with this */
pktgen_stop_device(pkt_dev);
@@ -3777,6 +3820,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
pkt_dev->svlan_id = 0xffff;
pkt_dev->burst = 1;
pkt_dev->node = NUMA_NO_NODE;
+ pkt_dev->flags = F_SHARED; /* SKB shared by default */
err = pktgen_setup_dev(t->net, pkt_dev, ifname);
if (err)