scst/iscsi-scst/kernel/patches/put_page_callback-3.12.11.patch

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index cc29cd3..ba34c70 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -130,7 +130,7 @@ static int page_chain_free(struct page *page)
 	struct page *tmp;
 	int i = 0;
 	page_chain_for_each_safe(page, tmp) {
-		put_page(page);
+		net_put_page(page);
 		++i;
 	}
 	return i;
diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 7e2788c..70d390c 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -1369,7 +1369,7 @@ vmxnet3_rq_cleanup(struct vmxnet3_rx_queue *rq,
 					rq->buf_info[ring_idx][i].page) {
 				dma_unmap_page(&adapter->pdev->dev, rxd->addr,
 					       rxd->len, PCI_DMA_FROMDEVICE);
-				put_page(rq->buf_info[ring_idx][i].page);
+				net_put_page(rq->buf_info[ring_idx][i].page);
 				rq->buf_info[ring_idx][i].page = NULL;
 			}
 		}
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 6255850..12a6f14 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1055,7 +1055,7 @@ static void xenvif_fill_frags(struct xenvif *vif, struct sk_buff *skb)
 		skb->truesize += txp->size;
 
 		/* Take an extra reference to offset xenvif_idx_release */
-		get_page(vif->mmap_pages[pending_idx]);
+		net_get_page(vif->mmap_pages[pending_idx]);
 		xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
 	}
 }
@@ -1525,7 +1525,7 @@ static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
 
 	} while (!pending_tx_is_head(vif, peek));
 
-	put_page(vif->mmap_pages[pending_idx]);
+	net_put_page(vif->mmap_pages[pending_idx]);
 	vif->mmap_pages[pending_idx] = NULL;
 }
 
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8e082f1..15f10c8 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -177,6 +177,17 @@ struct page {
 #ifdef LAST_NID_NOT_IN_PAGE_FLAGS
 	int _last_nid;
 #endif
+
+#if defined(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION)
+	/*
+	 * Used to implement support for notification on zero-copy TCP transfer
+	 * completion. It might look as not good to have this field here and
+	 * it's better to have it in struct sk_buff, but it would make the code
+	 * much more complicated and fragile, since all skb then would have to
+	 * contain only pages with the same value in this field.
+	 */
+	 void *net_priv;
+#endif
 }
 /*
  * The struct page can be forced to be double word aligned so that atomic ops
diff --git a/include/linux/net.h b/include/linux/net.h
index 41103f8..54c2bffb 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -19,6 +19,7 @@
 #define _LINUX_NET_H
 
 #include <linux/stringify.h>
+#include <linux/mm.h>
 #include <linux/random.h>
 #include <linux/wait.h>
 #include <linux/fcntl.h>	/* For O_CLOEXEC and O_NONBLOCK */
@@ -278,6 +279,45 @@ extern int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg);
 extern int kernel_sock_shutdown(struct socket *sock,
 				enum sock_shutdown_cmd how);
 
+#if defined(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION)
+/* Support for notification on zero-copy TCP transfer completion */
+typedef void (*net_get_page_callback_t)(struct page *page);
+typedef void (*net_put_page_callback_t)(struct page *page);
+
+extern net_get_page_callback_t net_get_page_callback;
+extern net_put_page_callback_t net_put_page_callback;
+
+extern int net_set_get_put_page_callbacks(
+	net_get_page_callback_t get_callback,
+	net_put_page_callback_t put_callback);
+
+/*
+ * See comment for net_set_get_put_page_callbacks() why those functions
+ * don't need any protection.
+ */
+static inline void net_get_page(struct page *page)
+{
+	if (page->net_priv != 0)
+		net_get_page_callback(page);
+	get_page(page);
+}
+static inline void net_put_page(struct page *page)
+{
+	if (page->net_priv != 0)
+		net_put_page_callback(page);
+	put_page(page);
+}
+#else
+static inline void net_get_page(struct page *page)
+{
+	get_page(page);
+}
+static inline void net_put_page(struct page *page)
+{
+	put_page(page);
+}
+#endif /* CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION */
+
 #define MODULE_ALIAS_NETPROTO(proto) \
 	MODULE_ALIAS("net-pf-" __stringify(proto))
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index efa1649..5efff79 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1975,7 +1975,7 @@ static inline struct page *skb_frag_page(const skb_frag_t *frag)
  */
 static inline void __skb_frag_ref(skb_frag_t *frag)
 {
-	get_page(skb_frag_page(frag));
+	net_get_page(skb_frag_page(frag));
 }
 
 /**
@@ -1998,7 +1998,7 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f)
  */
 static inline void __skb_frag_unref(skb_frag_t *frag)
 {
-	put_page(skb_frag_page(frag));
+	net_put_page(skb_frag_page(frag));
 }
 
 /**
diff --git a/net/Kconfig b/net/Kconfig
index b50dacc..88ed9df 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -75,6 +75,18 @@ config INET
 
 	  Short answer: say Y.
 
+config TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION
+	bool "TCP/IP zero-copy transfer completion notification"
+        depends on INET
+        default SCST_ISCSI
+	---help---
+	  Adds support for sending a notification upon completion of a
+          zero-copy TCP/IP transfer. This can speed up certain TCP/IP
+          software. Currently this is only used by the iSCSI target driver
+          iSCSI-SCST.
+
+          If unsure, say N.
+
 if INET
 source "net/ipv4/Kconfig"
 source "net/ipv6/Kconfig"
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c
index 815a224..f53c802 100644
--- a/net/ceph/pagevec.c
+++ b/net/ceph/pagevec.c
@@ -51,7 +51,7 @@ void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty)
 	for (i = 0; i < num_pages; i++) {
 		if (dirty)
 			set_page_dirty_lock(pages[i]);
-		put_page(pages[i]);
+		net_put_page(pages[i]);
 	}
 	kfree(pages);
 }
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2c7baa8..3196557 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -422,7 +422,7 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev,
 		if (likely(data)) {
 			skb = build_skb(data, fragsz);
 			if (unlikely(!skb))
-				put_page(virt_to_head_page(data));
+				net_put_page(virt_to_head_page(data));
 		}
 	} else {
 		skb = __alloc_skb(length + NET_SKB_PAD, gfp_mask,
@@ -468,7 +468,7 @@ static void skb_clone_fraglist(struct sk_buff *skb)
 static void skb_free_head(struct sk_buff *skb)
 {
 	if (skb->head_frag)
-		put_page(virt_to_head_page(skb->head));
+		net_put_page(virt_to_head_page(skb->head));
 	else
 		kfree(skb->head);
 }
@@ -793,7 +793,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
 		if (!page) {
 			while (head) {
 				struct page *next = (struct page *)page_private(head);
-				put_page(head);
+				net_put_page(head);
 				head = next;
 			}
 			return -ENOMEM;
@@ -1618,7 +1618,7 @@ EXPORT_SYMBOL(skb_copy_bits);
  */
 static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i)
 {
-	put_page(spd->pages[i]);
+	net_put_page(spd->pages[i]);
 }
 
 static struct page *linear_to_page(struct page *page, unsigned int *len,
@@ -1671,7 +1671,7 @@ static bool spd_fill_page(struct splice_pipe_desc *spd,
 		spd->partial[spd->nr_pages - 1].len += *len;
 		return false;
 	}
-	get_page(page);
+	net_get_page(page);
 	spd->pages[spd->nr_pages] = page;
 	spd->partial[spd->nr_pages].len = *len;
 	spd->partial[spd->nr_pages].offset = offset;
@@ -2675,7 +2675,7 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
 				   copy);
 		frg_cnt++;
 		pfrag->offset += copy;
-		get_page(pfrag->page);
+		net_get_page(pfrag->page);
 
 		skb->truesize += copy;
 		atomic_add(copy, &sk->sk_wmem_alloc);
diff --git a/net/core/sock.c b/net/core/sock.c
index 5cec994..c756279 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1847,7 +1847,7 @@ bool sk_page_frag_refill(struct sock *sk, struct page_frag *pfrag)
 		}
 		if (pfrag->offset < pfrag->size)
 			return true;
-		put_page(pfrag->page);
+		net_put_page(pfrag->page);
 	}
 
 	/* We restrict high order allocations to users that can afford to wait */
@@ -2599,7 +2599,7 @@ void sk_common_release(struct sock *sk)
 	sk_refcnt_debug_release(sk);
 
 	if (sk->sk_frag.page) {
-		put_page(sk->sk_frag.page);
+		net_put_page(sk->sk_frag.page);
 		sk->sk_frag.page = NULL;
 	}
 
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 4b81e91..b88113f 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
 obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
 obj-$(CONFIG_MEMCG_KMEM) += tcp_memcontrol.o
 obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
+obj-$(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION) += tcp_zero_copy.o
 
 obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
 		      xfrm4_output.o
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 3982eab..d37f078 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1003,7 +1003,7 @@ alloc_new_skb:
 				__skb_fill_page_desc(skb, i, pfrag->page,
 						     pfrag->offset, 0);
 				skb_shinfo(skb)->nr_frags = ++i;
-				get_page(pfrag->page);
+				net_get_page(pfrag->page);
 			}
 			copy = min_t(int, copy, pfrag->size - pfrag->offset);
 			if (getfrag(from,
@@ -1224,7 +1224,7 @@ ssize_t	ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 		if (skb_can_coalesce(skb, i, page, offset)) {
 			skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len);
 		} else if (i < MAX_SKB_FRAGS) {
-			get_page(page);
+			net_get_page(page);
 			skb_fill_page_desc(skb, i, page, offset, len);
 		} else {
 			err = -EMSGSIZE;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index be5246e..a349ddd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -896,7 +896,7 @@ new_segment:
 		if (can_coalesce) {
 			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
 		} else {
-			get_page(page);
+			net_get_page(page);
 			skb_fill_page_desc(skb, i, page, offset, copy);
 		}
 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
@@ -1192,7 +1192,7 @@ new_segment:
 				} else {
 					skb_fill_page_desc(skb, i, pfrag->page,
 							   pfrag->offset, copy);
-					get_page(pfrag->page);
+					net_get_page(pfrag->page);
 				}
 				pfrag->offset += copy;
 			}
diff --git a/net/ipv4/tcp_zero_copy.c b/net/ipv4/tcp_zero_copy.c
new file mode 100644
index 0000000..430147e
--- /dev/null
+++ b/net/ipv4/tcp_zero_copy.c
@@ -0,0 +1,50 @@
+/*
+ *	Support routines for TCP zero copy transmit
+ *
+ *	Created by Vladislav Bolkhovitin
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	version 2 as published by the Free Software Foundation.
+ */
+
+#include <linux/export.h>
+#include <linux/skbuff.h>
+
+net_get_page_callback_t net_get_page_callback __read_mostly;
+EXPORT_SYMBOL_GPL(net_get_page_callback);
+
+net_put_page_callback_t net_put_page_callback __read_mostly;
+EXPORT_SYMBOL_GPL(net_put_page_callback);
+
+/*
+ * Caller of this function must ensure that at the moment when it's called
+ * there are no pages in the system with net_priv field set to non-zero
+ * value. Hence, this function, as well as net_get_page() and net_put_page(),
+ * don't need any protection.
+ */
+int net_set_get_put_page_callbacks(
+	net_get_page_callback_t get_callback,
+	net_put_page_callback_t put_callback)
+{
+	int res = 0;
+
+	if ((net_get_page_callback != NULL) && (get_callback != NULL) &&
+	    (net_get_page_callback != get_callback)) {
+		res = -EBUSY;
+		goto out;
+	}
+
+	if ((net_put_page_callback != NULL) && (put_callback != NULL) &&
+	    (net_put_page_callback != put_callback)) {
+		res = -EBUSY;
+		goto out;
+	}
+
+	net_get_page_callback = get_callback;
+	net_put_page_callback = put_callback;
+
+out:
+	return res;
+}
+EXPORT_SYMBOL_GPL(net_set_get_put_page_callbacks);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index b6fa35e..b6f3389 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1413,7 +1413,7 @@ alloc_new_skb:
 				__skb_fill_page_desc(skb, i, pfrag->page,
 						     pfrag->offset, 0);
 				skb_shinfo(skb)->nr_frags = ++i;
-				get_page(pfrag->page);
+				net_get_page(pfrag->page);
 			}
 			copy = min_t(int, copy, pfrag->size - pfrag->offset);
 			if (getfrag(from,
diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index ae2e5c1..2ad9e87 100644
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -258,7 +258,7 @@ nfqnl_zcopy(struct sk_buff *to, const struct sk_buff *from, int len, int hlen)
 			page = virt_to_head_page(from->head);
 			offset = from->data - (unsigned char *)page_address(page);
 			__skb_fill_page_desc(to, 0, page, offset, plen);
-			get_page(page);
+			net_get_page(page);
 			j = 1;
 			len -= plen;
 		}
-- 
1.8.4.5