net: add __pskb_copy_fclone and pskb_copy_for_clone

There are several instances where a pskb_copy or __pskb_copy is
immediately followed by an skb_clone.

Add a couple of new functions to allow the copy skb to be allocated
from the fclone cache and thus speed up subsequent skb_clone calls.

Cc: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Marek Lindner <mareklindner@neomailbox.ch>
Cc: Simon Wunderlich <sw@simonwunderlich.de>
Cc: Antonio Quartulli <antonio@meshcoding.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: Arvid Brodin <arvid.brodin@alten.se>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Jon Maloy <jon.maloy@ericsson.com>
Cc: Allan Stephens <allan.stephens@windriver.com>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Reviewed-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 34 insertions, 16 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index c705808bef9c..1f50bfe2243d 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -744,7 +744,13 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
 int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask);
 struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t priority);
 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t priority);
-struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask);
+struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
+                                   gfp_t gfp_mask, bool fclone);
+static inline struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom,
+                                          gfp_t gfp_mask)
+{
+        return __pskb_copy_fclone(skb, headroom, gfp_mask, false);
+}
 
 int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail, gfp_t gfp_mask);
 struct sk_buff *skb_realloc_headroom(struct sk_buff *skb,
@@ -2238,6 +2244,14 @@ static inline struct sk_buff *pskb_copy(struct sk_buff *skb,
         return __pskb_copy(skb, skb_headroom(skb), gfp_mask);
 }
 
+
+static inline struct sk_buff *pskb_copy_for_clone(struct sk_buff *skb,
+                                                  gfp_t gfp_mask)
+{
+        return __pskb_copy_fclone(skb, skb_headroom(skb), gfp_mask, true);
+}
+
+
 /**
  *      skb_clone_writable - is the header of a clone writable
  *      @skb: buffer to check
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index dcd99b2bea3c..f2c066b21716 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -594,7 +594,7 @@ static bool batadv_dat_send_data(struct batadv_priv *bat_priv,
                 if (!neigh_node)
                         goto free_orig;
 
-                tmp_skb = pskb_copy(skb, GFP_ATOMIC);
+                tmp_skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
                 if (!batadv_send_skb_prepare_unicast_4addr(bat_priv, tmp_skb,
                                                            cand[i].orig_node,
                                                            packet_subtype)) {
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 40a2fc4bcf4c..8d04d174669e 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -1344,7 +1344,7 @@ static void batadv_nc_skb_store_before_coding(struct batadv_priv *bat_priv,
         struct ethhdr *ethhdr;
 
         /* Copy skb header to change the mac header */
-        skb = pskb_copy(skb, GFP_ATOMIC);
+        skb = pskb_copy_for_clone(skb, GFP_ATOMIC);
         if (!skb)
                 return;
 
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index f608bffdb8b9..80d25c150a65 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -143,7 +143,7 @@ void hci_send_to_sock(struct hci_dev *hdev, struct sk_buff *skb)
 
                 if (!skb_copy) {
                         /* Create a private copy with headroom */
-                        skb_copy = __pskb_copy(skb, 1, GFP_ATOMIC);
+                        skb_copy = __pskb_copy_fclone(skb, 1, GFP_ATOMIC, true);
                         if (!skb_copy)
                                 continue;
 
@@ -247,8 +247,8 @@ void hci_send_to_monitor(struct hci_dev *hdev, struct sk_buff *skb)
                         struct hci_mon_hdr *hdr;
 
                         /* Create a private copy with headroom */
-                        skb_copy = __pskb_copy(skb, HCI_MON_HDR_SIZE,
-                                               GFP_ATOMIC);
+                        skb_copy = __pskb_copy_fclone(skb, HCI_MON_HDR_SIZE,
+                                                      GFP_ATOMIC, true);
                         if (!skb_copy)
                                 continue;
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 05f4bef2ce12..b9e85e6cb26a 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -951,10 +951,13 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 EXPORT_SYMBOL(skb_copy);
 
 /**
- *      __pskb_copy     -       create copy of an sk_buff with private head.
+ *      __pskb_copy_fclone      -  create copy of an sk_buff with private head.
  *      @skb: buffer to copy
  *      @headroom: headroom of new skb
  *      @gfp_mask: allocation priority
+ *      @fclone: if true allocate the copy of the skb from the fclone
+ *      cache instead of the head cache; it is recommended to set this
+ *      to true for the cases where the copy will likely be cloned
  *
  *      Make a copy of both an &sk_buff and part of its data, located
  *      in header. Fragmented data remain shared. This is used when
@@ -964,11 +967,12 @@ EXPORT_SYMBOL(skb_copy);
  *      The returned buffer has a reference count of 1.
  */
 
-struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
+struct sk_buff *__pskb_copy_fclone(struct sk_buff *skb, int headroom,
+                                   gfp_t gfp_mask, bool fclone)
 {
         unsigned int size = skb_headlen(skb) + headroom;
-        struct sk_buff *n = __alloc_skb(size, gfp_mask,
-                                        skb_alloc_rx_flag(skb), NUMA_NO_NODE);
+        int flags = skb_alloc_rx_flag(skb) | (fclone ? SKB_ALLOC_FCLONE : 0);
+        struct sk_buff *n = __alloc_skb(size, gfp_mask, flags, NUMA_NO_NODE);
 
         if (!n)
                 goto out;
@@ -1008,7 +1012,7 @@ struct sk_buff *__pskb_copy(struct sk_buff *skb, int headroom, gfp_t gfp_mask)
 out:
         return n;
 }
-EXPORT_SYMBOL(__pskb_copy);
+EXPORT_SYMBOL(__pskb_copy_fclone);
 
 /**
  *      pskb_expand_head - reallocate header of &sk_buff
diff --git a/net/nfc/llcp_core.c b/net/nfc/llcp_core.c
index f6278da68763..51e788797317 100644
--- a/net/nfc/llcp_core.c
+++ b/net/nfc/llcp_core.c
@@ -680,8 +680,8 @@ void nfc_llcp_send_to_raw_sock(struct nfc_llcp_local *local,
                         continue;
 
                 if (skb_copy == NULL) {
-                        skb_copy = __pskb_copy(skb, NFC_RAW_HEADER_SIZE,
-                                               GFP_ATOMIC);
+                        skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
+                                                      GFP_ATOMIC, true);
 
                         if (skb_copy == NULL)
                                 continue;
diff --git a/net/nfc/rawsock.c b/net/nfc/rawsock.c
index 55eefee311eb..11c3544ea546 100644
--- a/net/nfc/rawsock.c
+++ b/net/nfc/rawsock.c
@@ -378,8 +378,8 @@ void nfc_send_to_raw_sock(struct nfc_dev *dev, struct sk_buff *skb,
 
         sk_for_each(sk, &raw_sk_list.head) {
                 if (!skb_copy) {
-                        skb_copy = __pskb_copy(skb, NFC_RAW_HEADER_SIZE,
-                                     GFP_ATOMIC);
+                        skb_copy = __pskb_copy_fclone(skb, NFC_RAW_HEADER_SIZE,
+                                                      GFP_ATOMIC, true);
                         if (!skb_copy)
                                 continue;
 
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 671f9817b4f4..26631679a1fa 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -653,7 +653,7 @@ static int tipc_bcbearer_send(struct sk_buff *buf, struct tipc_bearer *unused1,
                         tipc_bearer_send(b->identity, buf, &b->bcast_addr);
                 } else {
                         /* Avoid concurrent buffer access */
-                        tbuf = pskb_copy(buf, GFP_ATOMIC);
+                        tbuf = pskb_copy_for_clone(buf, GFP_ATOMIC);
                         if (!tbuf)
                                 break;
                         tipc_bearer_send(b->identity, tbuf, &b->bcast_addr);