Update for 3.5 kernel (merge r4458 from trunk)

git-svn-id: http://svn.code.sf.net/p/scst/svn/branches/2.2.x@4571 d57e44dd-8a1f-0410-8b47-8ef2f437770f
2026-05-18 11:11:27 +00:00 · 2012-11-03 13:27:32 +00:00
parent 2d2df09c5a
commit 2ae9bb3655
3 changed files with 874 additions and 4 deletions
--- a/iscsi-scst/kernel/patches/put_page_callback-3.5.patch
+++ b/iscsi-scst/kernel/patches/put_page_callback-3.5.patch
@@ -0,0 +1,328 @@
+=== modified file 'include/linux/mm_types.h'
+--- old/include/linux/mm_types.h	2012-08-08 02:57:29 +0000
+++ new/include/linux/mm_types.h	2012-08-08 22:59:04 +0000
+@@ -160,6 +160,17 @@ struct page {
+ 	 */
+ 	void *shadow;
+ #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	2012-08-08 02:57:29 +0000
+++ new/include/linux/net.h	2012-08-08 22:59:04 +0000
+@@ -61,6 +61,7 @@ typedef enum {
+ #include <linux/fcntl.h>	/* For O_CLOEXEC and O_NONBLOCK */
+ #include <linux/kmemcheck.h>
+ #include <linux/rcupdate.h>
+#include <linux/mm.h>
+ 
+ struct poll_table_struct;
+ struct pipe_inode_info;
+@@ -303,6 +304,45 @@ 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	2012-08-08 02:57:29 +0000
+++ new/include/linux/skbuff.h	2012-08-08 22:59:04 +0000
+@@ -1756,7 +1756,7 @@ 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));
+ }
+ 
+ /**
+@@ -1779,7 +1779,7 @@ 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	2012-08-08 02:57:29 +0000
+++ new/net/Kconfig	2012-08-08 22:59:04 +0000
+@@ -72,6 +72,18 @@ 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/core/skbuff.c'
+--- old/net/core/skbuff.c	2012-08-08 02:57:29 +0000
+++ new/net/core/skbuff.c	2012-08-08 22:59:04 +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,
+@@ -321,12 +321,12 @@ refill:
+ 	}
+ 	if (likely(nc->page)) {
+ 		if (nc->offset + fragsz > PAGE_SIZE) {
+-			put_page(nc->page);
+			net_put_page(nc->page);
+ 			goto refill;
+ 		}
+ 		data = page_address(nc->page) + nc->offset;
+ 		nc->offset += fragsz;
+-		get_page(nc->page);
+		net_get_page(nc->page);
+ 	}
+ 	local_irq_restore(flags);
+ 	return data;
+@@ -359,7 +359,7 @@ 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, 0, NUMA_NO_NODE);
+@@ -411,7 +411,7 @@ 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);
+ }
+@@ -742,7 +742,7 @@ int skb_copy_ubufs(struct sk_buff *skb,
+ 		if (!page) {
+ 			while (head) {
+ 				struct page *next = (struct page *)head->private;
+-				put_page(head);
+				net_put_page(head);
+ 				head = next;
+ 			}
+ 			return -ENOMEM;
+@@ -1568,7 +1568,7 @@ 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,
+@@ -1595,7 +1595,7 @@ new_page:
+ 		off = sk->sk_sndmsg_off;
+ 		mlen = PAGE_SIZE - off;
+ 		if (mlen < 64 && mlen < *len) {
+-			put_page(p);
+			net_put_page(p);
+ 			goto new_page;
+ 		}
+ 
+@@ -1640,7 +1640,7 @@ 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;
+
+=== modified file 'net/ipv4/Makefile'
+--- old/net/ipv4/Makefile	2012-08-08 02:57:29 +0000
+++ new/net/ipv4/Makefile	2012-08-08 22:59:04 +0000
+@@ -50,6 +50,7 @@ obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.
+ obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
+ obj-$(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) += tcp_memcontrol.o
+ obj-$(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	2012-08-08 02:57:29 +0000
+++ new/net/ipv4/ip_output.c	2012-08-08 22:59:04 +0000
+@@ -1245,7 +1245,7 @@ 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	2012-08-08 02:57:29 +0000
+++ new/net/ipv4/tcp.c	2012-08-08 22:59:04 +0000
+@@ -882,7 +882,7 @@ 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);
+ 		}
+ 
+@@ -1105,7 +1105,7 @@ new_segment:
+ 					goto new_segment;
+ 				} else if (page) {
+ 					if (off == PAGE_SIZE) {
+-						put_page(page);
+						net_put_page(page);
+ 						sk->sk_sndmsg_page = page = NULL;
+ 						off = 0;
+ 					}
+@@ -1145,9 +1145,9 @@ new_segment:
+ 				} else {
+ 					skb_fill_page_desc(skb, i, page, off, copy);
+ 					if (sk->sk_sndmsg_page) {
+-						get_page(page);
+						net_get_page(page);
+ 					} else if (off + copy < PAGE_SIZE) {
+-						get_page(page);
+						net_get_page(page);
+ 						sk->sk_sndmsg_page = page;
+ 					}
+ 				}
+
+=== 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	2012-08-08 22:59:04 +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);
+
--- a/scst/kernel/scst_exec_req_fifo-3.5.patch
+++ b/scst/kernel/scst_exec_req_fifo-3.5.patch
@@ -0,0 +1,527 @@
+=== modified file 'block/blk-map.c'
+--- old/block/blk-map.c	2012-08-08 02:57:29 +0000
+++ new/block/blk-map.c	2012-08-08 03:02:56 +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	2012-08-08 02:57:29 +0000
+++ new/include/linux/blkdev.h	2012-08-08 03:02:56 +0000
+@@ -627,6 +627,8 @@ 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);
+@@ -746,6 +748,9 @@ 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	2012-08-08 02:57:29 +0000
+++ new/include/linux/scatterlist.h	2012-08-08 03:02:56 +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 */
+@@ -220,6 +221,9 @@ size_t sg_copy_from_buffer(struct scatte
+ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+ 			 void *buf, size_t buflen);
+ 
+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	2012-08-08 02:57:29 +0000
+++ new/lib/scatterlist.c	2012-08-08 03:02:56 +0000
+@@ -517,3 +517,126 @@ size_t sg_copy_to_buffer(struct scatterl
+ 	return sg_copy_buffer(sgl, nents, buf, buflen, 1);
+ }
+ EXPORT_SYMBOL(sg_copy_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);
+
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -3005,8 +3005,10 @@ static int scst_check_auto_sense(struct scst_cmd *cmd)
 			scst_set_busy(cmd);
 		} else {
 			TRACE(TRACE_SCSI|TRACE_MINOR_AND_MGMT_DBG, "Host "
-				"status %x received, returning HARDWARE ERROR "
-				"instead (cmd %p)", cmd->host_status, cmd);
+				"status 0x%x received, returning HARDWARE ERROR "
+				"instead (cmd %p, op 0x%x, target %s, device "
+				"%s)", cmd->host_status, cmd, cmd->cdb[0],
+				cmd->tgt->tgt_name, cmd->dev->virt_name);
 			scst_set_cmd_error(cmd,
 				SCST_LOAD_SENSE(scst_sense_hardw_error));
 		}
@@ -4114,11 +4116,24 @@ static void scst_ioctx_get(struct scst_cmd_threads *p_cmd_threads)
 			 */
 			put_io_context(p_cmd_threads->io_context);
 		} else {
-			current->io_context =
-				ioc_task_link(p_cmd_threads->io_context);
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0) && (LINUX_VERSION_CODE <= KERNEL_VERSION(3, 6, 0)))
+#warning IO context sharing functionality disabled on 3.5 kernels due to bug in them. \
+See "http://lkml.org/lkml/2012/7/17/515" for more details.
+			static int q;
+			if (q == 0) {
+				q++;
+				PRINT_WARNING("%s", "IO context sharing functionality "
+					"disabled on 3.5 kernels due to bug in "
+					"them. See http://lkml.org/lkml/2012/7/17/515 "
+					"for more details.");
+			}
+#else
+			ioc_task_link(p_cmd_threads->io_context);
+			current->io_context = p_cmd_threads->io_context;
 			TRACE_MGMT_DBG("Linked IO context %p "
 				"(p_cmd_threads %p)", p_cmd_threads->io_context,
 				p_cmd_threads);
+#endif
 		}
 		p_cmd_threads->io_context_refcnt++;
 	}