datapath: Always use GFP_ATOMIC to execute actions.

These functions run 99% of the time in atomic context and the benefit of
passing along the 'gfp' argument for the other 1% doesn't seem to outweigh
the cost.

Suggested-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/datapath/actions.c b/datapath/actions.c
index 050e373..5365278 100644 (file)
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -25,13 +25,13 @@
 #include "openvswitch/datapath-protocol.h"
 #include "vport.h"
 
-static struct sk_buff *make_writable(struct sk_buff *skb, unsigned min_headroom, gfp_t gfp)
+static struct sk_buff *make_writable(struct sk_buff *skb, unsigned min_headroom)
 {
        if (skb_cloned(skb)) {
                struct sk_buff *nskb;
                unsigned headroom = max(min_headroom, skb_headroom(skb));
 
-               nskb = skb_copy_expand(skb, headroom, skb_tailroom(skb), gfp);
+               nskb = skb_copy_expand(skb, headroom, skb_tailroom(skb), GFP_ATOMIC);
                if (nskb) {
                        set_skb_csum_bits(skb, nskb);
                        kfree_skb(skb);
@@ -72,13 +72,12 @@ static struct sk_buff *vlan_pull_tag(struct sk_buff *skb)
 
 static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                                       const struct odp_flow_key *key,
-                                      const union odp_action *a, int n_actions,
-                                      gfp_t gfp)
+                                      const union odp_action *a, int n_actions)
 {
        __be16 mask = a->dl_tci.mask;
        __be16 tci = a->dl_tci.tci;
 
-       skb = make_writable(skb, VLAN_HLEN, gfp);
+       skb = make_writable(skb, VLAN_HLEN);
        if (!skb)
                return ERR_PTR(-ENOMEM);
 
@@ -154,8 +153,7 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
                                if (segs) {
                                        err = execute_actions(dp, segs,
                                                              key, a + 1,
-                                                             n_actions - 1,
-                                                             gfp);
+                                                             n_actions - 1);
                                }
 
                                if (unlikely(err)) {
@@ -193,19 +191,18 @@ static struct sk_buff *modify_vlan_tci(struct datapath *dp, struct sk_buff *skb,
        return skb;
 }
 
-static struct sk_buff *strip_vlan(struct sk_buff *skb, gfp_t gfp)
+static struct sk_buff *strip_vlan(struct sk_buff *skb)
 {
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb)
                vlan_pull_tag(skb);
        return skb;
 }
 
 static struct sk_buff *set_dl_addr(struct sk_buff *skb,
-                                  const struct odp_action_dl_addr *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_dl_addr *a)
 {
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb) {
                struct ethhdr *eh = eth_hdr(skb);
                if (a->type == ODPAT_SET_DL_SRC)
@@ -257,8 +254,7 @@ static __sum16 *get_l4_checksum(struct sk_buff *skb, const struct odp_flow_key *
 
 static struct sk_buff *set_nw_addr(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_nw_addr *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_nw_addr *a)
 {
        struct iphdr *nh;
        __sum16 *check;
@@ -267,7 +263,7 @@ static struct sk_buff *set_nw_addr(struct sk_buff *skb,
        if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (unlikely(!skb))
                return NULL;
 
@@ -286,13 +282,12 @@ static struct sk_buff *set_nw_addr(struct sk_buff *skb,
 
 static struct sk_buff *set_nw_tos(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_nw_tos *a,
-                                  gfp_t gfp)
+                                  const struct odp_action_nw_tos *a)
 {
        if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (skb) {
                struct iphdr *nh = ip_hdr(skb);
                u8 *f = &nh->tos;
@@ -310,7 +305,7 @@ static struct sk_buff *set_nw_tos(struct sk_buff *skb,
 
 static struct sk_buff *set_tp_port(struct sk_buff *skb,
                                   const struct odp_flow_key *key,
-                                  const struct odp_action_tp_port *a, gfp_t gfp)
+                                  const struct odp_action_tp_port *a)
 {
        struct udphdr *th;
        __sum16 *check;
@@ -319,7 +314,7 @@ static struct sk_buff *set_tp_port(struct sk_buff *skb,
        if (unlikely(!is_ip(skb, key)))
                return skb;
 
-       skb = make_writable(skb, 0, gfp);
+       skb = make_writable(skb, 0);
        if (unlikely(!skb))
                return NULL;
 
@@ -390,10 +385,9 @@ error:
        kfree_skb(skb);
 }
 
-static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg,
-                         gfp_t gfp)
+static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg)
 {
-       skb = skb_clone(skb, gfp);
+       skb = skb_clone(skb, GFP_ATOMIC);
        if (!skb)
                return -ENOMEM;
        return dp_output_control(dp, skb, _ODPL_ACTION_NR, arg);
@@ -403,14 +397,14 @@ static int output_control(struct datapath *dp, struct sk_buff *skb, u32 arg,
  * information about what happened to it. */
 static void sflow_sample(struct datapath *dp, struct sk_buff *skb,
                         const union odp_action *a, int n_actions,
-                        gfp_t gfp, struct dp_port *dp_port)
+                        struct dp_port *dp_port)
 {
        struct odp_sflow_sample_header *hdr;
        unsigned int actlen = n_actions * sizeof(union odp_action);
        unsigned int hdrlen = sizeof(struct odp_sflow_sample_header);
        struct sk_buff *nskb;
 
-       nskb = skb_copy_expand(skb, actlen + hdrlen, 0, gfp);
+       nskb = skb_copy_expand(skb, actlen + hdrlen, 0, GFP_ATOMIC);
        if (!nskb)
                return;
 
@@ -424,8 +418,7 @@ static void sflow_sample(struct datapath *dp, struct sk_buff *skb,
 /* Execute a list of actions against 'skb'. */
 int execute_actions(struct datapath *dp, struct sk_buff *skb,
                    const struct odp_flow_key *key,
-                   const union odp_action *a, int n_actions,
-                   gfp_t gfp)
+                   const union odp_action *a, int n_actions)
 {
        /* Every output action needs a separate clone of 'skb', but the common
         * case is just a single output action, so that doing a clone and
@@ -441,7 +434,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        atomic_inc(&p->sflow_pool);
                        if (dp->sflow_probability == UINT_MAX ||
                            net_random() < dp->sflow_probability)
-                               sflow_sample(dp, skb, a, n_actions, gfp, p);
+                               sflow_sample(dp, skb, a, n_actions, p);
                }
        }
 
@@ -449,7 +442,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
 
        for (; n_actions > 0; a++, n_actions--) {
                if (prev_port != -1) {
-                       do_output(dp, skb_clone(skb, gfp), prev_port);
+                       do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
                        prev_port = -1;
                }
 
@@ -459,7 +452,7 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        break;
 
                case ODPAT_CONTROLLER:
-                       err = output_control(dp, skb, a->controller.arg, gfp);
+                       err = output_control(dp, skb, a->controller.arg);
                        if (err) {
                                kfree_skb(skb);
                                return err;
@@ -471,32 +464,32 @@ int execute_actions(struct datapath *dp, struct sk_buff *skb,
                        break;
 
                case ODPAT_SET_DL_TCI:
-                       skb = modify_vlan_tci(dp, skb, key, a, n_actions, gfp);
+                       skb = modify_vlan_tci(dp, skb, key, a, n_actions);
                        if (IS_ERR(skb))
                                return PTR_ERR(skb);
                        break;
 
                case ODPAT_STRIP_VLAN:
-                       skb = strip_vlan(skb, gfp);
+                       skb = strip_vlan(skb);
                        break;
 
                case ODPAT_SET_DL_SRC:
                case ODPAT_SET_DL_DST:
-                       skb = set_dl_addr(skb, &a->dl_addr, gfp);
+                       skb = set_dl_addr(skb, &a->dl_addr);
                        break;
 
                case ODPAT_SET_NW_SRC:
                case ODPAT_SET_NW_DST:
-                       skb = set_nw_addr(skb, key, &a->nw_addr, gfp);
+                       skb = set_nw_addr(skb, key, &a->nw_addr);
                        break;
 
                case ODPAT_SET_NW_TOS:
-                       skb = set_nw_tos(skb, key, &a->nw_tos, gfp);
+                       skb = set_nw_tos(skb, key, &a->nw_tos);
                        break;
 
                case ODPAT_SET_TP_SRC:
                case ODPAT_SET_TP_DST:
-                       skb = set_tp_port(skb, key, &a->tp_port, gfp);
+                       skb = set_tp_port(skb, key, &a->tp_port);
                        break;
 
                case ODPAT_SET_PRIORITY:

diff --git a/datapath/actions.h b/datapath/actions.h
index da4f4bf..f2962a7 100644 (file)
--- a/datapath/actions.h
+++ b/datapath/actions.h
@@ -9,7 +9,6 @@
 #ifndef ACTIONS_H
 #define ACTIONS_H 1
 
-#include <linux/gfp.h>
 #include <linux/skbuff.h>
 #include <linux/version.h>
 
@@ -20,8 +19,7 @@ union odp_action;
 
 int execute_actions(struct datapath *dp, struct sk_buff *skb,
                    const struct odp_flow_key *key,
-                   const union odp_action *, int n_actions,
-                   gfp_t gfp);
+                   const union odp_action *, int n_actions);
 
 static inline void set_skb_csum_bits(const struct sk_buff *old_skb,
                                     struct sk_buff *new_skb)

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 46497c6..eddc4ab 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -591,7 +591,7 @@ void dp_process_received_packet(struct dp_port *p, struct sk_buff *skb)
 
        /* Execute actions. */
        execute_actions(dp, skb, &OVS_CB(skb)->flow->key, acts->actions,
-                       acts->n_actions, GFP_ATOMIC);
+                       acts->n_actions);
        stats_counter_off = offsetof(struct dp_stats_percpu, n_hit);
 
        /* Check whether sub-actions looped too much. */
@@ -1376,8 +1376,7 @@ static int do_execute(struct datapath *dp, const struct odp_execute *execute)
                goto error_free_skb;
 
        rcu_read_lock();
-       err = execute_actions(dp, skb, &key, actions->actions,
-                             actions->n_actions, GFP_KERNEL);
+       err = execute_actions(dp, skb, &key, actions->actions, actions->n_actions);
        rcu_read_unlock();
 
        kfree(actions);

diff --git a/datapath/flow.h b/datapath/flow.h
index 25b7204..b1e8005 100644 (file)
--- a/datapath/flow.h
+++ b/datapath/flow.h
@@ -13,7 +13,6 @@
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/rcupdate.h>
-#include <linux/gfp.h>
 #include <linux/if_ether.h>
 #include <linux/jiffies.h>
 #include <linux/time.h>