[PATCH net-next v2 6/6] net: dsa: factor skb freeing on xmit
From: Vivien Didelot
Date: Tue May 30 2017 - 14:37:37 EST
The taggers are currently responsible to free the original SKB if they
made a copy of it, or in case of error.
This patch simplifies this by freeing the original SKB in the
dsa_slave_xmit caller, but only if an error (NULL) is returned.
It is still the responsibility of the tagger to free the original SKB if
it returned a copy of it.
At the same time, fix the checkpatch NULL comparison check:
CHECK: Comparison to NULL could be written "!nskb"
#208: FILE: net/dsa/tag_trailer.c:35:
+ if (nskb == NULL)
Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
---
net/dsa/slave.c | 8 ++++++--
net/dsa/tag_brcm.c | 6 +-----
net/dsa/tag_dsa.c | 8 ++------
net/dsa/tag_edsa.c | 8 ++------
net/dsa/tag_lan9303.c | 5 +----
net/dsa/tag_mtk.c | 6 +-----
net/dsa/tag_qca.c | 6 +-----
net/dsa/tag_trailer.c | 4 +---
8 files changed, 15 insertions(+), 36 deletions(-)
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 887e26695519..4473aec9dcda 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -362,10 +362,14 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
dev->stats.tx_packets++;
dev->stats.tx_bytes += skb->len;
- /* Transmit function may have to reallocate the original SKB */
+ /* Transmit function may have to reallocate the original SKB,
+ * in which case it must have freed it. Only free it here on error.
+ */
nskb = p->xmit(skb, dev);
- if (!nskb)
+ if (!nskb) {
+ kfree_skb(skb);
return NETDEV_TX_OK;
+ }
/* SKB for netpoll still need to be mangled with the protocol-specific
* tag to be successfully transmitted
diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index 10fa4c0ca46b..5db6bcfde025 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -65,7 +65,7 @@ static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev
u8 *brcm_tag;
if (skb_cow_head(skb, BRCM_TAG_LEN) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, BRCM_TAG_LEN);
@@ -86,10 +86,6 @@ static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev
brcm_tag[3] = (1 << p->dp->index) & BRCM_IG_DSTMAP1_MASK;
return skb;
-
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index 9f5fecaa4a93..6837ca9160a8 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -28,7 +28,7 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
*/
if (skb->protocol == htons(ETH_P_8021Q)) {
if (skb_cow_head(skb, 0) < 0)
- goto out_free;
+ return NULL;
/*
* Construct tagged FROM_CPU DSA tag from 802.1q tag.
@@ -46,7 +46,7 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
}
} else {
if (skb_cow_head(skb, DSA_HLEN) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, DSA_HLEN);
memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
@@ -62,10 +62,6 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev)
}
return skb;
-
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c
index a9a06e19abeb..96ddc90472a2 100644
--- a/net/dsa/tag_edsa.c
+++ b/net/dsa/tag_edsa.c
@@ -30,7 +30,7 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
*/
if (skb->protocol == htons(ETH_P_8021Q)) {
if (skb_cow_head(skb, DSA_HLEN) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, DSA_HLEN);
memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN);
@@ -55,7 +55,7 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
}
} else {
if (skb_cow_head(skb, EDSA_HLEN) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, EDSA_HLEN);
memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN);
@@ -75,10 +75,6 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev)
}
return skb;
-
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c
index 82e150486497..e33348101e8f 100644
--- a/net/dsa/tag_lan9303.c
+++ b/net/dsa/tag_lan9303.c
@@ -52,7 +52,7 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) {
dev_dbg(&dev->dev,
"Cannot make room for the special tag. Dropping packet\n");
- goto out_free;
+ return NULL;
}
/* provide 'LAN9303_TAG_LEN' bytes additional space */
@@ -66,9 +66,6 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
lan9303_tag[1] = htons(p->dp->index | BIT(4));
return skb;
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index 327dd7b596df..ee62ae5f03e1 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -27,7 +27,7 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
u8 *mtk_tag;
if (skb_cow_head(skb, MTK_HDR_LEN) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, MTK_HDR_LEN);
@@ -41,10 +41,6 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
mtk_tag[3] = 0;
return skb;
-
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index 8080ad8f2abb..4d3bc2920477 100644
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -45,7 +45,7 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
dev->stats.tx_bytes += skb->len;
if (skb_cow_head(skb, 0) < 0)
- goto out_free;
+ return NULL;
skb_push(skb, QCA_HDR_LEN);
@@ -60,10 +60,6 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
*phdr = htons(hdr);
return skb;
-
-out_free:
- kfree_skb(skb);
- return NULL;
}
static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev)
diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c
index 7422b1329712..8c9a7f5ecc66 100644
--- a/net/dsa/tag_trailer.c
+++ b/net/dsa/tag_trailer.c
@@ -32,10 +32,8 @@ static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev)
padlen = 60 - skb->len;
nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC);
- if (nskb == NULL) {
- kfree_skb(skb);
+ if (!nskb)
return NULL;
- }
skb_reserve(nskb, NET_IP_ALIGN);
skb_reset_mac_header(nskb);
--
2.13.0