Add support for kernel 3.12 (merge r5163 from the trunk)

git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/2.2.x@5167 d57e44dd-8a1f-0410-8b47-8ef2f437770f

iscsi-scst/kernel/patches/put_page_callback-3.12.patch

@@ -0,0 +1,419 @@
+=== modified file 'drivers/block/drbd/drbd_receiver.c'
+--- old/drivers/block/drbd/drbd_receiver.c	2013-11-30 00:34:22 +0000
++++ new/drivers/block/drbd/drbd_receiver.c	2013-11-30 00:55:02 +0000
+@@ -130,7 +130,7 @@ static int page_chain_free(struct page *
+ 	struct page *tmp;
+ 	int i = 0;
+ 	page_chain_for_each_safe(page, tmp) {
+-		put_page(page);
++		net_put_page(page);
+ 		++i;
+ 	}
+ 	return i;
+
+=== modified file 'drivers/net/vmxnet3/vmxnet3_drv.c'
+--- old/drivers/net/vmxnet3/vmxnet3_drv.c	2013-11-30 00:34:22 +0000
++++ new/drivers/net/vmxnet3/vmxnet3_drv.c	2013-11-30 00:55:02 +0000
+@@ -1369,7 +1369,7 @@ vmxnet3_rq_cleanup(struct vmxnet3_rx_que
+ 					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;
+ 			}
+ 		}
+
+=== modified file 'drivers/net/xen-netback/netback.c'
+--- old/drivers/net/xen-netback/netback.c	2013-11-30 00:34:22 +0000
++++ new/drivers/net/xen-netback/netback.c	2013-11-30 00:55:02 +0000
+@@ -1054,7 +1054,7 @@ static void xenvif_fill_frags(struct xen
+ 		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);
+ 	}
+ }
+@@ -1524,7 +1524,7 @@ static void xenvif_idx_release(struct xe
+ 
+ 	} 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;
+ }
+ 
+
+=== modified file 'include/linux/mm_types.h'
+--- old/include/linux/mm_types.h	2013-11-30 00:34:22 +0000
++++ new/include/linux/mm_types.h	2013-11-30 00:55:02 +0000
+@@ -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
+
+=== modified file 'include/linux/net.h'
+--- old/include/linux/net.h	2013-11-30 00:34:22 +0000
++++ new/include/linux/net.h	2013-11-30 00:55:02 +0000
+@@ -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 */
+@@ -270,6 +271,45 @@ extern int kernel_sock_ioctl(struct sock
+ 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))
+ 
+
+=== modified file 'include/linux/skbuff.h'
+--- old/include/linux/skbuff.h	2013-11-30 00:34:22 +0000
++++ new/include/linux/skbuff.h	2013-11-30 00:55:02 +0000
+@@ -1979,7 +1979,7 @@ static inline struct page *skb_frag_page
+  */
+ static inline void __skb_frag_ref(skb_frag_t *frag)
+ {
+-	get_page(skb_frag_page(frag));
++	net_get_page(skb_frag_page(frag));
+ }
+ 
+ /**
+@@ -2002,7 +2002,7 @@ static inline void skb_frag_ref(struct s
+  */
+ static inline void __skb_frag_unref(skb_frag_t *frag)
+ {
+-	put_page(skb_frag_page(frag));
++	net_put_page(skb_frag_page(frag));
+ }
+ 
+ /**
+
+=== modified file 'net/Kconfig'
+--- old/net/Kconfig	2013-11-30 00:34:22 +0000
++++ new/net/Kconfig	2013-11-30 00:55:02 +0000
+@@ -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"
+
+=== modified file 'net/ceph/pagevec.c'
+--- old/net/ceph/pagevec.c	2013-11-30 00:34:22 +0000
++++ new/net/ceph/pagevec.c	2013-11-30 00:55:02 +0000
+@@ -51,7 +51,7 @@ void ceph_put_page_vector(struct page **
+ 	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);
+ }
+
+=== modified file 'net/core/skbuff.c'
+--- old/net/core/skbuff.c	2013-11-30 00:34:22 +0000
++++ new/net/core/skbuff.c	2013-11-30 00:55:02 +0000
+@@ -77,13 +77,13 @@ static struct kmem_cache *skbuff_fclone_
+ static void sock_pipe_buf_release(struct pipe_inode_info *pipe,
+ 				  struct pipe_buffer *buf)
+ {
+-	put_page(buf->page);
++	net_put_page(buf->page);
+ }
+ 
+ static void sock_pipe_buf_get(struct pipe_inode_info *pipe,
+ 				struct pipe_buffer *buf)
+ {
+-	get_page(buf->page);
++	net_get_page(buf->page);
+ }
+ 
+ static int sock_pipe_buf_steal(struct pipe_inode_info *pipe,
+@@ -452,7 +452,7 @@ struct sk_buff *__netdev_alloc_skb(struc
+ 		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,
+@@ -498,7 +498,7 @@ static void skb_clone_fraglist(struct sk
+ 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);
+ }
+@@ -826,7 +826,7 @@ int skb_copy_ubufs(struct sk_buff *skb,
+ 		if (!page) {
+ 			while (head) {
+ 				struct page *next = (struct page *)page_private(head);
+-				put_page(head);
++				net_put_page(head);
+ 				head = next;
+ 			}
+ 			return -ENOMEM;
+@@ -1651,7 +1651,7 @@ 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,
+@@ -1704,7 +1704,7 @@ static bool spd_fill_page(struct splice_
+ 		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;
+@@ -2708,7 +2708,7 @@ int skb_append_datato_frags(struct sock
+ 				   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);
+
+=== modified file 'net/core/sock.c'
+--- old/net/core/sock.c	2013-11-30 00:34:22 +0000
++++ new/net/core/sock.c	2013-11-30 00:55:02 +0000
+@@ -1847,7 +1847,7 @@ bool sk_page_frag_refill(struct sock *sk
+ 		}
+ 		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;
+ 	}
+ 
+
+=== modified file 'net/ipv4/Makefile'
+--- old/net/ipv4/Makefile	2013-11-30 00:34:22 +0000
++++ new/net/ipv4/Makefile	2013-11-30 00:55:02 +0000
+@@ -53,6 +53,7 @@ obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.
+ obj-$(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
+
+=== modified file 'net/ipv4/ip_output.c'
+--- old/net/ipv4/ip_output.c	2013-11-30 00:34:22 +0000
++++ new/net/ipv4/ip_output.c	2013-11-30 00:55:02 +0000
+@@ -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,
+ 		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;
+
+=== modified file 'net/ipv4/tcp.c'
+--- old/net/ipv4/tcp.c	2013-11-30 00:34:22 +0000
++++ new/net/ipv4/tcp.c	2013-11-30 00:55:02 +0000
+@@ -902,7 +902,7 @@ 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;
+@@ -1198,7 +1198,7 @@ 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;
+ 			}
+
+=== added file 'net/ipv4/tcp_zero_copy.c'
+--- old/net/ipv4/tcp_zero_copy.c	1970-01-01 00:00:00 +0000
++++ new/net/ipv4/tcp_zero_copy.c	2013-11-30 00:55:02 +0000
+@@ -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);
+
+=== modified file 'net/ipv6/ip6_output.c'
+--- old/net/ipv6/ip6_output.c	2013-11-30 00:34:22 +0000
++++ new/net/ipv6/ip6_output.c	2013-11-30 00:55:02 +0000
+@@ -1412,7 +1412,7 @@ 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,
+
+=== modified file 'net/netfilter/nfnetlink_queue_core.c'
+--- old/net/netfilter/nfnetlink_queue_core.c	2013-11-30 00:34:22 +0000
++++ new/net/netfilter/nfnetlink_queue_core.c	2013-11-30 00:55:02 +0000
+@@ -258,7 +258,7 @@ nfqnl_zcopy(struct sk_buff *to, const st
+ 			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;
+ 		}
+

scst/kernel/scst_exec_req_fifo-3.12.patch

@@ -0,0 +1,528 @@
+=== modified file 'block/blk-map.c'
+--- old/block/blk-map.c	2013-11-30 00:34:22 +0000
++++ new/block/blk-map.c	2013-11-30 00:39:53 +0000
+@@ -5,6 +5,8 @@
+ #include <linux/module.h>
+ #include <linux/bio.h>
+ #include <linux/blkdev.h>
++#include <linux/scatterlist.h>
++#include <linux/slab.h>
+ #include <scsi/sg.h>		/* for struct sg_iovec */
+ 
+ #include "blk.h"
+@@ -275,6 +277,337 @@ int blk_rq_unmap_user(struct bio *bio)
+ }
+ EXPORT_SYMBOL(blk_rq_unmap_user);
+ 
++struct blk_kern_sg_work {
++	atomic_t bios_inflight;
++	struct sg_table sg_table;
++	struct scatterlist *src_sgl;
++};
++
++static void blk_free_kern_sg_work(struct blk_kern_sg_work *bw)
++{
++	struct sg_table *sgt = &bw->sg_table;
++	struct scatterlist *sg;
++	int i;
++
++	for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
++		struct page *pg = sg_page(sg);
++		if (pg == NULL)
++			break;
++		__free_page(pg);
++	}
++
++	sg_free_table(sgt);
++	kfree(bw);
++	return;
++}
++
++static void blk_bio_map_kern_endio(struct bio *bio, int err)
++{
++	struct blk_kern_sg_work *bw = bio->bi_private;
++
++	if (bw != NULL) {
++		/* Decrement the bios in processing and, if zero, free */
++		BUG_ON(atomic_read(&bw->bios_inflight) <= 0);
++		if (atomic_dec_and_test(&bw->bios_inflight)) {
++			if ((bio_data_dir(bio) == READ) && (err == 0)) {
++				unsigned long flags;
++
++				local_irq_save(flags);	/* to protect KMs */
++				sg_copy(bw->src_sgl, bw->sg_table.sgl, 0, 0);
++				local_irq_restore(flags);
++			}
++			blk_free_kern_sg_work(bw);
++		}
++	}
++
++	bio_put(bio);
++	return;
++}
++
++static int blk_rq_copy_kern_sg(struct request *rq, struct scatterlist *sgl,
++			       int nents, struct blk_kern_sg_work **pbw,
++			       gfp_t gfp, gfp_t page_gfp)
++{
++	int res = 0, i;
++	struct scatterlist *sg;
++	struct scatterlist *new_sgl;
++	int new_sgl_nents;
++	size_t len = 0, to_copy;
++	struct blk_kern_sg_work *bw;
++
++	bw = kzalloc(sizeof(*bw), gfp);
++	if (bw == NULL)
++		goto out;
++
++	bw->src_sgl = sgl;
++
++	for_each_sg(sgl, sg, nents, i)
++		len += sg->length;
++	to_copy = len;
++
++	new_sgl_nents = PFN_UP(len);
++
++	res = sg_alloc_table(&bw->sg_table, new_sgl_nents, gfp);
++	if (res != 0)
++		goto err_free;
++
++	new_sgl = bw->sg_table.sgl;
++
++	for_each_sg(new_sgl, sg, new_sgl_nents, i) {
++		struct page *pg;
++
++		pg = alloc_page(page_gfp);
++		if (pg == NULL)
++			goto err_free;
++
++		sg_assign_page(sg, pg);
++		sg->length = min_t(size_t, PAGE_SIZE, len);
++
++		len -= PAGE_SIZE;
++	}
++
++	if (rq_data_dir(rq) == WRITE) {
++		/*
++		 * We need to limit amount of copied data to to_copy, because
++		 * sgl might have the last element in sgl not marked as last in
++		 * SG chaining.
++		 */
++		sg_copy(new_sgl, sgl, 0, to_copy);
++	}
++
++	*pbw = bw;
++	/*
++	 * REQ_COPY_USER name is misleading. It should be something like
++	 * REQ_HAS_TAIL_SPACE_FOR_PADDING.
++	 */
++	rq->cmd_flags |= REQ_COPY_USER;
++
++out:
++	return res;
++
++err_free:
++	blk_free_kern_sg_work(bw);
++	res = -ENOMEM;
++	goto out;
++}
++
++static int __blk_rq_map_kern_sg(struct request *rq, struct scatterlist *sgl,
++	int nents, struct blk_kern_sg_work *bw, gfp_t gfp)
++{
++	int res;
++	struct request_queue *q = rq->q;
++	int rw = rq_data_dir(rq);
++	int max_nr_vecs, i;
++	size_t tot_len;
++	bool need_new_bio;
++	struct scatterlist *sg, *prev_sg = NULL;
++	struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
++	int bios;
++
++	if (unlikely((sgl == NULL) || (sgl->length == 0) || (nents <= 0))) {
++		WARN_ON(1);
++		res = -EINVAL;
++		goto out;
++	}
++
++	/*
++	 * Let's keep each bio allocation inside a single page to decrease
++	 * probability of failure.
++	 */
++	max_nr_vecs =  min_t(size_t,
++		((PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec)),
++		BIO_MAX_PAGES);
++
++	need_new_bio = true;
++	tot_len = 0;
++	bios = 0;
++	for_each_sg(sgl, sg, nents, i) {
++		struct page *page = sg_page(sg);
++		void *page_addr = page_address(page);
++		size_t len = sg->length, l;
++		size_t offset = sg->offset;
++
++		tot_len += len;
++		prev_sg = sg;
++
++		/*
++		 * Each segment must be aligned on DMA boundary and
++		 * not on stack. The last one may have unaligned
++		 * length as long as the total length is aligned to
++		 * DMA padding alignment.
++		 */
++		if (i == nents - 1)
++			l = 0;
++		else
++			l = len;
++		if (((sg->offset | l) & queue_dma_alignment(q)) ||
++		    (page_addr && object_is_on_stack(page_addr + sg->offset))) {
++			res = -EINVAL;
++			goto out_free_bios;
++		}
++
++		while (len > 0) {
++			size_t bytes;
++			int rc;
++
++			if (need_new_bio) {
++				bio = bio_kmalloc(gfp, max_nr_vecs);
++				if (bio == NULL) {
++					res = -ENOMEM;
++					goto out_free_bios;
++				}
++
++				if (rw == WRITE)
++					bio->bi_rw |= REQ_WRITE;
++
++				bios++;
++				bio->bi_private = bw;
++				bio->bi_end_io = blk_bio_map_kern_endio;
++
++				if (hbio == NULL)
++					hbio = tbio = bio;
++				else
++					tbio = tbio->bi_next = bio;
++			}
++
++			bytes = min_t(size_t, len, PAGE_SIZE - offset);
++
++			rc = bio_add_pc_page(q, bio, page, bytes, offset);
++			if (rc < bytes) {
++				if (unlikely(need_new_bio || (rc < 0))) {
++					if (rc < 0)
++						res = rc;
++					else
++						res = -EIO;
++					goto out_free_bios;
++				} else {
++					need_new_bio = true;
++					len -= rc;
++					offset += rc;
++					continue;
++				}
++			}
++
++			need_new_bio = false;
++			offset = 0;
++			len -= bytes;
++			page = nth_page(page, 1);
++		}
++	}
++
++	if (hbio == NULL) {
++		res = -EINVAL;
++		goto out_free_bios;
++	}
++
++	/* Total length must be aligned on DMA padding alignment */
++	if ((tot_len & q->dma_pad_mask) &&
++	    !(rq->cmd_flags & REQ_COPY_USER)) {
++		res = -EINVAL;
++		goto out_free_bios;
++	}
++
++	if (bw != NULL)
++		atomic_set(&bw->bios_inflight, bios);
++
++	while (hbio != NULL) {
++		bio = hbio;
++		hbio = hbio->bi_next;
++		bio->bi_next = NULL;
++
++		blk_queue_bounce(q, &bio);
++
++		res = blk_rq_append_bio(q, rq, bio);
++		if (unlikely(res != 0)) {
++			bio->bi_next = hbio;
++			hbio = bio;
++			/* We can have one or more bios bounced */
++			goto out_unmap_bios;
++		}
++	}
++
++	res = 0;
++
++	rq->buffer = NULL;
++out:
++	return res;
++
++out_unmap_bios:
++	blk_rq_unmap_kern_sg(rq, res);
++
++out_free_bios:
++	while (hbio != NULL) {
++		bio = hbio;
++		hbio = hbio->bi_next;
++		bio_put(bio);
++	}
++	goto out;
++}
++
++/**
++ * blk_rq_map_kern_sg - map kernel data to a request, for REQ_TYPE_BLOCK_PC
++ * @rq:		request to fill
++ * @sgl:	area to map
++ * @nents:	number of elements in @sgl
++ * @gfp:	memory allocation flags
++ *
++ * Description:
++ *    Data will be mapped directly if possible. Otherwise a bounce
++ *    buffer will be used.
++ */
++int blk_rq_map_kern_sg(struct request *rq, struct scatterlist *sgl,
++		       int nents, gfp_t gfp)
++{
++	int res;
++
++	res = __blk_rq_map_kern_sg(rq, sgl, nents, NULL, gfp);
++	if (unlikely(res != 0)) {
++		struct blk_kern_sg_work *bw = NULL;
++
++		res = blk_rq_copy_kern_sg(rq, sgl, nents, &bw,
++				gfp, rq->q->bounce_gfp | gfp);
++		if (unlikely(res != 0))
++			goto out;
++
++		res = __blk_rq_map_kern_sg(rq, bw->sg_table.sgl,
++				bw->sg_table.nents, bw, gfp);
++		if (res != 0) {
++			blk_free_kern_sg_work(bw);
++			goto out;
++		}
++	}
++
++	rq->buffer = NULL;
++
++out:
++	return res;
++}
++EXPORT_SYMBOL(blk_rq_map_kern_sg);
++
++/**
++ * blk_rq_unmap_kern_sg - unmap a request with kernel sg
++ * @rq:		request to unmap
++ * @err:	non-zero error code
++ *
++ * Description:
++ *    Unmap a rq previously mapped by blk_rq_map_kern_sg(). Must be called
++ *    only in case of an error!
++ */
++void blk_rq_unmap_kern_sg(struct request *rq, int err)
++{
++	struct bio *bio = rq->bio;
++
++	while (bio) {
++		struct bio *b = bio;
++		bio = bio->bi_next;
++		b->bi_end_io(b, err);
++	}
++	rq->bio = NULL;
++
++	return;
++}
++EXPORT_SYMBOL(blk_rq_unmap_kern_sg);
++
+ /**
+  * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
+  * @q:		request queue where request should be inserted
+
+=== modified file 'include/linux/blkdev.h'
+--- old/include/linux/blkdev.h	2013-11-30 00:34:22 +0000
++++ new/include/linux/blkdev.h	2013-11-30 00:39:53 +0000
+@@ -676,6 +676,8 @@ extern unsigned long blk_max_low_pfn, bl
+ #define BLK_DEFAULT_SG_TIMEOUT	(60 * HZ)
+ #define BLK_MIN_SG_TIMEOUT	(7 * HZ)
+ 
++#define SCSI_EXEC_REQ_FIFO_DEFINED
++
+ #ifdef CONFIG_BOUNCE
+ extern int init_emergency_isa_pool(void);
+ extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
+@@ -795,6 +797,9 @@ extern int blk_rq_map_kern(struct reques
+ extern int blk_rq_map_user_iov(struct request_queue *, struct request *,
+ 			       struct rq_map_data *, struct sg_iovec *, int,
+ 			       unsigned int, gfp_t);
++extern int blk_rq_map_kern_sg(struct request *rq, struct scatterlist *sgl,
++			      int nents, gfp_t gfp);
++extern void blk_rq_unmap_kern_sg(struct request *rq, int err);
+ extern int blk_execute_rq(struct request_queue *, struct gendisk *,
+ 			  struct request *, int);
+ extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
+
+=== modified file 'include/linux/scatterlist.h'
+--- old/include/linux/scatterlist.h	2013-11-30 00:34:22 +0000
++++ new/include/linux/scatterlist.h	2013-11-30 00:39:53 +0000
+@@ -8,6 +8,7 @@
+ #include <asm/types.h>
+ #include <asm/scatterlist.h>
+ #include <asm/io.h>
++#include <asm/kmap_types.h>
+ 
+ struct sg_table {
+ 	struct scatterlist *sgl;	/* the list */
+@@ -249,6 +250,9 @@ size_t sg_pcopy_from_buffer(struct scatt
+ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+ 			  void *buf, size_t buflen, off_t skip);
+ 
++int sg_copy(struct scatterlist *dst_sg, struct scatterlist *src_sg,
++	    int nents_to_copy, size_t copy_len);
++
+ /*
+  * Maximum number of entries that will be allocated in one piece, if
+  * a list larger than this is required then chaining will be utilized.
+
+=== modified file 'lib/scatterlist.c'
+--- old/lib/scatterlist.c	2013-11-30 00:34:22 +0000
++++ new/lib/scatterlist.c	2013-11-30 00:39:53 +0000
+@@ -717,3 +717,127 @@ size_t sg_pcopy_to_buffer(struct scatter
+ 	return sg_copy_buffer(sgl, nents, buf, buflen, skip, true);
+ }
+ EXPORT_SYMBOL(sg_pcopy_to_buffer);
++
++
++/*
++ * Can switch to the next dst_sg element, so, to copy to strictly only
++ * one dst_sg element, it must be either last in the chain, or
++ * copy_len == dst_sg->length.
++ */
++static int sg_copy_elem(struct scatterlist **pdst_sg, size_t *pdst_len,
++			size_t *pdst_offs, struct scatterlist *src_sg,
++			size_t copy_len)
++{
++	int res = 0;
++	struct scatterlist *dst_sg;
++	size_t src_len, dst_len, src_offs, dst_offs;
++	struct page *src_page, *dst_page;
++
++	dst_sg = *pdst_sg;
++	dst_len = *pdst_len;
++	dst_offs = *pdst_offs;
++	dst_page = sg_page(dst_sg);
++
++	src_page = sg_page(src_sg);
++	src_len = src_sg->length;
++	src_offs = src_sg->offset;
++
++	do {
++		void *saddr, *daddr;
++		size_t n;
++
++		saddr = kmap_atomic(src_page + (src_offs >> PAGE_SHIFT)) +
++				    (src_offs & ~PAGE_MASK);
++		daddr = kmap_atomic(dst_page + (dst_offs >> PAGE_SHIFT)) +
++				    (dst_offs & ~PAGE_MASK);
++
++		if (((src_offs & ~PAGE_MASK) == 0) &&
++		    ((dst_offs & ~PAGE_MASK) == 0) &&
++		    (src_len >= PAGE_SIZE) && (dst_len >= PAGE_SIZE) &&
++		    (copy_len >= PAGE_SIZE)) {
++			copy_page(daddr, saddr);
++			n = PAGE_SIZE;
++		} else {
++			n = min_t(size_t, PAGE_SIZE - (dst_offs & ~PAGE_MASK),
++					  PAGE_SIZE - (src_offs & ~PAGE_MASK));
++			n = min(n, src_len);
++			n = min(n, dst_len);
++			n = min_t(size_t, n, copy_len);
++			memcpy(daddr, saddr, n);
++		}
++		dst_offs += n;
++		src_offs += n;
++
++		kunmap_atomic(saddr);
++		kunmap_atomic(daddr);
++
++		res += n;
++		copy_len -= n;
++		if (copy_len == 0)
++			goto out;
++
++		src_len -= n;
++		dst_len -= n;
++		if (dst_len == 0) {
++			dst_sg = sg_next(dst_sg);
++			if (dst_sg == NULL)
++				goto out;
++			dst_page = sg_page(dst_sg);
++			dst_len = dst_sg->length;
++			dst_offs = dst_sg->offset;
++		}
++	} while (src_len > 0);
++
++out:
++	*pdst_sg = dst_sg;
++	*pdst_len = dst_len;
++	*pdst_offs = dst_offs;
++	return res;
++}
++
++/**
++ * sg_copy - copy one SG vector to another
++ * @dst_sg:	destination SG
++ * @src_sg:	source SG
++ * @nents_to_copy: maximum number of entries to copy
++ * @copy_len:	maximum amount of data to copy. If 0, then copy all.
++ *
++ * Description:
++ *    Data from the source SG vector will be copied to the destination SG
++ *    vector. End of the vectors will be determined by sg_next() returning
++ *    NULL. Returns number of bytes copied.
++ */
++int sg_copy(struct scatterlist *dst_sg, struct scatterlist *src_sg,
++	    int nents_to_copy, size_t copy_len)
++{
++	int res = 0;
++	size_t dst_len, dst_offs;
++
++	if (copy_len == 0)
++		copy_len = 0x7FFFFFFF; /* copy all */
++
++	if (nents_to_copy == 0)
++		nents_to_copy = 0x7FFFFFFF; /* copy all */
++
++	dst_len = dst_sg->length;
++	dst_offs = dst_sg->offset;
++
++	do {
++		int copied = sg_copy_elem(&dst_sg, &dst_len, &dst_offs,
++				src_sg, copy_len);
++		copy_len -= copied;
++		res += copied;
++		if ((copy_len == 0) || (dst_sg == NULL))
++			goto out;
++
++		nents_to_copy--;
++		if (nents_to_copy == 0)
++			goto out;
++
++		src_sg = sg_next(src_sg);
++	} while (src_sg != NULL);
++
++out:
++	return res;
++}
++EXPORT_SYMBOL(sg_copy);
+

scst/src/scst_mem.c

@@ -218,7 +218,7 @@ static bool sgv_purge_from_cache(struct sgv_pool_obj *obj, int min_interval,
 
 /* No locks */
 static int sgv_shrink_pool(struct sgv_pool *pool, int nr, int min_interval,
-	unsigned long cur_time)
+	unsigned long cur_time, int *out_freed)
 {
 	int freed = 0;
 
@@ -266,12 +266,14 @@ static int sgv_shrink_pool(struct sgv_pool *pool, int nr, int min_interval,
 	spin_unlock_bh(&pool->sgv_pool_lock);
 
 out:
+	*out_freed += freed;
+
 	TRACE_EXIT_RES(nr);
 	return nr;
 }
 
 /* No locks */
-static int __sgv_shrink(int nr, int min_interval)
+static int __sgv_shrink(int nr, int min_interval, int *out_freed)
 {
 	struct sgv_pool *pool;
 	unsigned long cur_time = jiffies;
@@ -320,7 +322,7 @@ static int __sgv_shrink(int nr, int min_interval)
 
 		spin_unlock_bh(&sgv_pools_lock);
 
-		nr = sgv_shrink_pool(pool, nr, min_interval, cur_time);
+		nr = sgv_shrink_pool(pool, nr, min_interval, cur_time, out_freed);
 
 		sgv_pool_put(pool);
 	}
@@ -339,6 +341,45 @@ out_unlock_put:
 	goto out;
 }
 
+unsigned long sgv_can_be_shrinked(struct shrinker *shrinker,
+	struct shrink_control *sc)
+{
+	unsigned long res;
+	struct sgv_pool *pool;
+	int inactive_pages = 0;
+
+	TRACE_ENTRY();
+
+	spin_lock_bh(&sgv_pools_lock);
+	list_for_each_entry(pool, &sgv_active_pools_list,
+			sgv_active_pools_list_entry) {
+		if (pool->purge_interval > 0)
+			inactive_pages += pool->inactive_cached_pages;
+	}
+	spin_unlock_bh(&sgv_pools_lock);
+
+	res = max((int)0, inactive_pages - sgv_lo_wmk);
+	TRACE_MEM("Can free %ld (total %d)", res, atomic_read(&sgv_pages_total));
+
+	TRACE_EXIT_RES(res);
+	return res;
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 12, 0)
+unsigned long sgv_scan_shrink(struct shrinker *shrinker,
+	struct shrink_control *sc)
+{
+	int freed = 0;
+
+	TRACE_ENTRY();
+
+	__sgv_shrink(sc->nr_to_scan, SGV_MIN_SHRINK_INTERVAL, &freed);
+	TRACE_MEM("Freed %d", freed);
+
+	TRACE_EXIT_RES(freed);
+	return freed;
+}
+#else /* if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 12, 0) */
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 35) && (!defined(RHEL_MAJOR) || RHEL_MAJOR -0 < 6)
 static int sgv_shrink(int nr, gfp_t gfpm)
 #elif LINUX_VERSION_CODE < KERNEL_VERSION(3, 0, 0)
@@ -350,32 +391,20 @@ static int sgv_shrink(struct shrinker *shrinker, struct shrink_control *sc)
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 0, 0)
 	int nr = sc->nr_to_scan;
 #endif
+	int freed = 0;
 
 	TRACE_ENTRY();
 
 	if (nr > 0) {
-		nr = __sgv_shrink(nr, SGV_MIN_SHRINK_INTERVAL);
+		nr = __sgv_shrink(nr, SGV_MIN_SHRINK_INTERVAL, &freed);
 		TRACE_MEM("Left %d", nr);
-	} else {
-		struct sgv_pool *pool;
-		int inactive_pages = 0;
-
-		spin_lock_bh(&sgv_pools_lock);
-		list_for_each_entry(pool, &sgv_active_pools_list,
-				sgv_active_pools_list_entry) {
-			if (pool->purge_interval > 0)
-				inactive_pages += pool->inactive_cached_pages;
-		}
-		spin_unlock_bh(&sgv_pools_lock);
-
-		nr = max((int)0, inactive_pages - sgv_lo_wmk);
-		TRACE_MEM("Can free %d (total %d)", nr,
-			atomic_read(&sgv_pages_total));
-	}
+	} else
+		nr = sgv_can_be_shrinked(shrinker, sc);
 
 	TRACE_EXIT_RES(nr);
 	return nr;
 }
+#endif /* if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 12, 0) */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 20)
 static void sgv_purge_work_fn(void *p)
@@ -823,10 +852,12 @@ static int sgv_hiwmk_check(int pages_to_alloc)
 	pages += atomic_read(&sgv_pages_total);
 
 	if (unlikely(pages > sgv_hi_wmk)) {
+		int freed = 0;
+
 		pages -= sgv_hi_wmk;
 		atomic_inc(&sgv_releases_on_hiwmk);
 
-		pages = __sgv_shrink(pages, 0);
+		pages = __sgv_shrink(pages, 0, &freed);
 		if (pages > 0) {
 			TRACE(TRACE_OUT_OF_MEM, "Requested amount of "
 			    "memory (%d pages) for being executed "
@@ -1752,8 +1783,13 @@ int scst_sgv_pools_init(unsigned long mem_hwmark, unsigned long mem_lwmark)
 
 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 23))
 	sgv_shrinker = set_shrinker(DEFAULT_SEEKS, sgv_shrink);
+#else
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 12, 0)
+	sgv_shrinker.count_objects = sgv_can_be_shrinked;
+	sgv_shrinker.scan_objects = sgv_scan_shrink;
 #else
 	sgv_shrinker.shrink = sgv_shrink;
+#endif
 	sgv_shrinker.seeks = DEFAULT_SEEKS;
 	register_shrinker(&sgv_shrinker);
 #endif