[net-next-2.6] Revert "net: Allow no-cache copy from user on transmit"

From 4d5767a1c0037f9acf051eb1d52a111308de8208 Mon Sep 17 00:00:00 2001
From: Sedat Dilek <sedat.dilek@gmail.com>
Date: Thu, 7 Apr 2011 10:07:05 +0200
Subject: [PATCH 01/10] Revert "net: Allow no-cache copy from user on transmit"

This reverts commit c6e1a0d12ca7b4f22c58e55a16beacfb7d3d8462.
---
 drivers/net/bonding/bond_main.c |    2 +-
 include/linux/netdevice.h       |    3 +-
 include/net/sock.h              |   53 ---------------------------------------
 net/core/dev.c                  |   12 ---------
 net/core/ethtool.c              |    2 +-
 net/ipv4/tcp.c                  |    7 ++---
 6 files changed, 6 insertions(+), 73 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index b51e021..16d6fe9 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1407,7 +1407,7 @@  static int bond_compute_features(struct bonding *bond)
 	int i;
 
 	features &= ~(NETIF_F_ALL_CSUM | BOND_VLAN_FEATURES);
-	features |=  NETIF_F_GSO_MASK | NETIF_F_NO_CSUM | NETIF_F_NOCACHE_COPY;
+	features |=  NETIF_F_GSO_MASK | NETIF_F_NO_CSUM;
 
 	if (!bond->first_slave)
 		goto done;
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 09d2624..a4664cc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1066,7 +1066,6 @@  struct net_device {
 #define NETIF_F_NTUPLE		(1 << 27) /* N-tuple filters supported */
 #define NETIF_F_RXHASH		(1 << 28) /* Receive hashing offload */
 #define NETIF_F_RXCSUM		(1 << 29) /* Receive checksumming offload */
-#define NETIF_F_NOCACHE_COPY	(1 << 30) /* Use no-cache copyfromuser */
 
 	/* Segmentation offload features */
 #define NETIF_F_GSO_SHIFT	16
@@ -1082,7 +1081,7 @@  struct net_device {
 	/* = all defined minus driver/device-class-related */
 #define NETIF_F_NEVER_CHANGE	(NETIF_F_HIGHDMA | NETIF_F_VLAN_CHALLENGED | \
 				  NETIF_F_LLTX | NETIF_F_NETNS_LOCAL)
-#define NETIF_F_ETHTOOL_BITS	(0x7f3fffff & ~NETIF_F_NEVER_CHANGE)
+#define NETIF_F_ETHTOOL_BITS	(0x3f3fffff & ~NETIF_F_NEVER_CHANGE)
 
 	/* List of features with software fallbacks. */
 #define NETIF_F_GSO_SOFTWARE	(NETIF_F_TSO | NETIF_F_TSO_ECN | \
diff --git a/include/net/sock.h b/include/net/sock.h
index 43bd515..da0534d 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -52,7 +52,6 @@ 
 #include <linux/mm.h>
 #include <linux/security.h>
 #include <linux/slab.h>
-#include <linux/uaccess.h>
 
 #include <linux/filter.h>
 #include <linux/rculist_nulls.h>
@@ -1390,58 +1389,6 @@  static inline void sk_nocaps_add(struct sock *sk, int flags)
 	sk->sk_route_caps &= ~flags;
 }
 
-static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
-					   char __user *from, char *to,
-					   int copy)
-{
-	if (skb->ip_summed == CHECKSUM_NONE) {
-		int err = 0;
-		__wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
-		if (err)
-			return err;
-		skb->csum = csum_block_add(skb->csum, csum, skb->len);
-	} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
-		if (!access_ok(VERIFY_READ, from, copy) ||
-		    __copy_from_user_nocache(to, from, copy))
-			return -EFAULT;
-	} else if (copy_from_user(to, from, copy))
-		return -EFAULT;
-
-	return 0;
-}
-
-static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
-				       char __user *from, int copy)
-{
-	int err;
-
-	err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy), copy);
-	if (err)
-		__skb_trim(skb, skb->len);
-
-	return err;
-}
-
-static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
-					   struct sk_buff *skb,
-					   struct page *page,
-					   int off, int copy)
-{
-	int err;
-
-	err = skb_do_copy_data_nocache(sk, skb, from,
-				       page_address(page) + off, copy);
-	if (err)
-		return err;
-
-	skb->len	     += copy;
-	skb->data_len	     += copy;
-	skb->truesize	     += copy;
-	sk->sk_wmem_queued   += copy;
-	sk_mem_charge(sk, copy);
-	return 0;
-}
-
 static inline int skb_copy_to_page(struct sock *sk, char __user *from,
 				   struct sk_buff *skb, struct page *page,
 				   int off, int copy)
diff --git a/net/core/dev.c b/net/core/dev.c
index 5d0b4f6..02f5637 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5425,14 +5425,6 @@  int register_netdevice(struct net_device *dev)
 		dev->features &= ~NETIF_F_GSO;
 	}
 
-	/* Turn on no cache copy if HW is doing checksum */
-	dev->hw_features |= NETIF_F_NOCACHE_COPY;
-	if ((dev->features & NETIF_F_ALL_CSUM) &&
-	    !(dev->features & NETIF_F_NO_CSUM)) {
-		dev->wanted_features |= NETIF_F_NOCACHE_COPY;
-		dev->features |= NETIF_F_NOCACHE_COPY;
-	}
-
 	/* Enable GRO and NETIF_F_HIGHDMA for vlans by default,
 	 * vlan_dev_init() will do the dev->features check, so these features
 	 * are enabled only if supported by underlying device.
@@ -6190,10 +6182,6 @@  u32 netdev_increment_features(u32 all, u32 one, u32 mask)
 		}
 	}
 
-	/* If device can't no cache copy, don't do for all */
-	if (!(one & NETIF_F_NOCACHE_COPY))
-		all &= ~NETIF_F_NOCACHE_COPY;
-
 	one |= NETIF_F_ALL_CSUM;
 
 	one |= all & NETIF_F_ONE_FOR_ALL;
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 719670a..439e4b0 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -359,7 +359,7 @@  static const char netdev_features_strings[ETHTOOL_DEV_FEATURE_WORDS * 32][ETH_GS
 	/* NETIF_F_NTUPLE */          "rx-ntuple-filter",
 	/* NETIF_F_RXHASH */          "rx-hashing",
 	/* NETIF_F_RXCSUM */          "rx-checksum",
-	/* NETIF_F_NOCACHE_COPY */    "tx-nocache-copy"
+	"",
 	"",
 };
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 054a59d..b22d450 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -999,8 +999,7 @@  new_segment:
 				/* We have some space in skb head. Superb! */
 				if (copy > skb_tailroom(skb))
 					copy = skb_tailroom(skb);
-				err = skb_add_data_nocache(sk, skb, from, copy);
-				if (err)
+				if ((err = skb_add_data(skb, from, copy)) != 0)
 					goto do_fault;
 			} else {
 				int merge = 0;
@@ -1043,8 +1042,8 @@  new_segment:
 
 				/* Time to copy data. We are close to
 				 * the end! */
-				err = skb_copy_to_page_nocache(sk, from, skb,
-							       page, off, copy);
+				err = skb_copy_to_page(sk, from, skb, page,
+						       off, copy);
 				if (err) {
 					/* If this page was new, give it to the
 					 * socket so it does not get leaked.
-- 
1.7.4.3