add performance improvement for madwifi on low-memory systems

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@10850 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 178 insertions, 0 deletions

diff --git a/package/madwifi/patches/350-performance.patch b/package/madwifi/patches/350-performance.patch
new file mode 100644
index 0000000000..e88c084dbf
--- /dev/null
+++ b/package/madwifi/patches/350-performance.patch
@@ -0,0 +1,178 @@
+Index: madwifi-trunk-r3314/ath/if_ath.c
+===================================================================
+--- madwifi-trunk-r3314.orig/ath/if_ath.c	2008-04-17 02:56:31.000000000 +0200
++++ madwifi-trunk-r3314/ath/if_ath.c	2008-04-17 03:20:28.000000000 +0200
+@@ -3237,7 +3237,6 @@
+ 	struct ath_softc *sc = dev->priv;
+ 	struct ieee80211_node *ni = NULL;
+ 	struct ath_buf *bf = NULL;
+-	struct ether_header *eh;
+ 	ath_bufhead bf_head;
+ 	struct ath_buf *tbf, *tempbf;
+ 	struct sk_buff *tskb;
+@@ -3249,6 +3248,7 @@
+ 	*/
+ 	int requeue = 0;
+ #ifdef ATH_SUPERG_FF
++	struct ether_header *eh;
+ 	unsigned int pktlen;
+ 	struct ieee80211com *ic = &sc->sc_ic;
+ 	struct ath_node *an;
+@@ -3314,27 +3314,9 @@
+ 		requeue = 1;
+ 		goto hardstart_fail;
+ 	}
+-#endif
+ 
+-	/* If the skb data is shared, we will copy it so we can strip padding
+-	 * without affecting any other bridge ports. */
+-	if (skb_cloned(skb)) {
+-		/* Remember the original SKB so we can free up our references */
+-		struct sk_buff *skb_new;
+-		skb_new = skb_copy(skb, GFP_ATOMIC);
+-		if (skb_new == NULL) {
+-			DPRINTF(sc, ATH_DEBUG_XMIT,
+-				"Dropping; skb_copy failure.\n");
+-			/* No free RAM, do not requeue! */
+-			goto hardstart_fail;
+-		}
+-		ieee80211_skb_copy_noderef(skb, skb_new);
+-		ieee80211_dev_kfree_skb(&skb);
+-		skb = skb_new;
+-	}
+ 	eh = (struct ether_header *)skb->data;
+ 
+-#ifdef ATH_SUPERG_FF
+ 	/* NB: use this lock to protect an->an_tx_ffbuf (and txq->axq_stageq)
+ 	 *     in athff_can_aggregate() call too. */
+ 	ATH_TXQ_LOCK_IRQ(txq);
+Index: madwifi-trunk-r3314/net80211/ieee80211_output.c
+===================================================================
+--- madwifi-trunk-r3314.orig/net80211/ieee80211_output.c	2008-04-17 02:56:30.000000000 +0200
++++ madwifi-trunk-r3314/net80211/ieee80211_output.c	2008-04-17 04:29:06.000000000 +0200
+@@ -615,100 +615,45 @@
+ 		skb = skb_unshare(skb, GFP_ATOMIC);
+ 	}
+ 
+-#ifdef ATH_SUPERG_FF
+-	if (isff) {
+-		if (skb == NULL) {
++	if (skb_cloned(skb) ||
++		(need_headroom > skb_headroom(skb)) ||
++		(!isff && (need_tailroom > skb_tailroom(skb)))) {
++
++		if (pskb_expand_head(skb, need_headroom, need_tailroom, GFP_ATOMIC)) {
+ 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-				"%s: cannot unshare for encapsulation\n",
+-				__func__);
++				"%s: cannot expand storage (tail)\n", __func__);
+ 			vap->iv_stats.is_tx_nobuf++;
+-			ieee80211_dev_kfree_skb(&skb2);
+-
++			ieee80211_dev_kfree_skb(&skb);
+ 			return NULL;
+ 		}
++	}
+ 
+-		/* first skb header */
+-		if (skb_headroom(skb) < need_headroom) {
+-			struct sk_buff *tmp = skb;
+-			skb = skb_realloc_headroom(skb, need_headroom);
+-			if (skb == NULL) {
+-				IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-					"%s: cannot expand storage (head1)\n",
+-					__func__);
+-				vap->iv_stats.is_tx_nobuf++;
+-				ieee80211_dev_kfree_skb(&skb2);
+-				return NULL;
+-			} else
+-				ieee80211_skb_copy_noderef(tmp, skb);
+-			ieee80211_dev_kfree_skb(&tmp);
+-			/* NB: cb[] area was copied, but not next ptr. must do that
+-			 *     prior to return on success. */
++#ifdef ATH_SUPERG_FF
++	if (isff) {
++		if (skb_shared(skb2)) {
++			/* Take our own reference to the node in the clone */
++			ieee80211_ref_node(SKB_CB(skb2)->ni);
++			/* Unshare the node, decrementing users in the old skb */
++			skb2 = skb_unshare(skb2, GFP_ATOMIC);
+ 		}
+ 
+-		/* second skb with header and tail adjustments possible */
+-		if (skb_tailroom(skb2) < need_tailroom) {
+-			int n = 0;
+-			if (inter_headroom > skb_headroom(skb2))
+-				n = inter_headroom - skb_headroom(skb2);
+-			if (pskb_expand_head(skb2, n,
+-			    need_tailroom - skb_tailroom(skb2), GFP_ATOMIC)) {
+-				ieee80211_dev_kfree_skb(&skb2);
+-				IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-					"%s: cannot expand storage (tail2)\n",
+-					__func__);
+-				vap->iv_stats.is_tx_nobuf++;
+-				/* this shouldn't happen, but don't send first ff either */
+-				ieee80211_dev_kfree_skb(&skb);
+-			}
+-		} else if (skb_headroom(skb2) < inter_headroom) {
+-			struct sk_buff *tmp = skb2;
++		if ((skb_cloned(skb2) ||
++			(inter_headroom > skb_headroom(skb2)) ||
++			(need_tailroom > skb_tailroom(skb2)))) {
+ 
+-			skb2 = skb_realloc_headroom(skb2, inter_headroom);
+-			if (skb2 == NULL) {
++			if (pskb_expand_head(skb2, inter_headroom,
++				need_tailroom, GFP_ATOMIC)) {
+ 				IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-					"%s: cannot expand storage (head2)\n",
+-					__func__);
++					"%s: cannot expand storage (tail)\n", __func__);
+ 				vap->iv_stats.is_tx_nobuf++;
+-				/* this shouldn't happen, but don't send first ff either */
+ 				ieee80211_dev_kfree_skb(&skb);
+-				skb = NULL;
+-			} else
+-				ieee80211_skb_copy_noderef(tmp, skb);
+-			ieee80211_dev_kfree_skb(&tmp);
+-		}
+-		if (skb) {
+-			skb->next = skb2;
++				ieee80211_dev_kfree_skb(&skb2);
++				return NULL;
++			}
+ 		}
+-		return skb;
++		skb->next = skb2;
+ 	}
+ #endif /* ATH_SUPERG_FF */
+-	if (skb == NULL) {
+-		IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-			"%s: cannot unshare for encapsulation\n", __func__);
+-		vap->iv_stats.is_tx_nobuf++;
+-	} else if (skb_tailroom(skb) < need_tailroom) {
+-		int n = 0;
+-		if (need_headroom > skb_headroom(skb))
+-			n = need_headroom - skb_headroom(skb);
+-		if (pskb_expand_head(skb, n, need_tailroom - 
+-					skb_tailroom(skb), GFP_ATOMIC)) {
+-			IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-				"%s: cannot expand storage (tail)\n", __func__);
+-			vap->iv_stats.is_tx_nobuf++;
+-			ieee80211_dev_kfree_skb(&skb);
+-		}
+-	} else if (skb_headroom(skb) < need_headroom) {
+-		struct sk_buff *tmp = skb;
+-		skb = skb_realloc_headroom(skb, need_headroom);
+-		/* Increment reference count after copy */
+-		if (skb == NULL) {
+-			IEEE80211_DPRINTF(vap, IEEE80211_MSG_OUTPUT,
+-				"%s: cannot expand storage (head)\n", __func__);
+-			vap->iv_stats.is_tx_nobuf++;
+-		} else
+-			ieee80211_skb_copy_noderef(tmp, skb);
+-		ieee80211_dev_kfree_skb(&tmp);
+-	}
+ 
+ 	return skb;
+ }