scst/www/sgv_big_order_alloc-sfw5-rc3.diff

Index: scst/include/scst_sgv.h
===================================================================
--- scst/include/scst_sgv.h	(revision 3134)
+++ scst/include/scst_sgv.h	(working copy)
@@ -82,12 +82,14 @@ void sgv_pool_put(struct sgv_pool *pool)
 void sgv_pool_flush(struct sgv_pool *pool);
 
 void sgv_pool_set_allocator(struct sgv_pool *pool,
-	struct page *(*alloc_pages_fn)(struct scatterlist *, gfp_t, void *),
-	void (*free_pages_fn)(struct scatterlist *, int, void *));
+	struct page *(*alloc_pages_fn)(struct scatterlist *,
+				       gfp_t, int, void *),
+	void (*free_pages_fn)(struct scatterlist *, int, int, void *));
 
 struct scatterlist *sgv_pool_alloc(struct sgv_pool *pool, unsigned int size,
 	gfp_t gfp_mask, int flags, int *count,
-	struct sgv_pool_obj **sgv, struct scst_mem_lim *mem_lim, void *priv);
+	struct sgv_pool_obj **sgv, struct scst_mem_lim *mem_lim, void *priv,
+	int max_sg_count);
 void sgv_pool_free(struct sgv_pool_obj *sgv, struct scst_mem_lim *mem_lim);
 
 void *sgv_get_priv(struct sgv_pool_obj *sgv);
Index: scst/src/scst_mem.h
===================================================================
--- scst/src/scst_mem.h	(revision 3134)
+++ scst/src/scst_mem.h	(working copy)
@@ -37,6 +37,8 @@ struct sgv_pool_obj {
 	int cache_num;
 	int pages;
 
+	int alloc_order;
+
 	/* jiffies, protected by sgv_pool_lock */
 	unsigned long time_stamp;
 
@@ -66,9 +68,9 @@ struct sgv_pool_cache_acc {
  */
 struct sgv_pool_alloc_fns {
 	struct page *(*alloc_pages_fn)(struct scatterlist *sg, gfp_t gfp_mask,
-		void *priv);
+		int alloc_order, void *priv);
 	void (*free_pages_fn)(struct scatterlist *sg, int sg_count,
-		void *priv);
+		int alloc_order, void *priv);
 };
 
 /*
Index: scst/src/scst_lib.c
===================================================================
--- scst/src/scst_lib.c	(revision 3134)
+++ scst/src/scst_lib.c	(working copy)
@@ -4454,7 +4454,6 @@ int scst_alloc_space(struct scst_cmd *cm
 	int atomic = scst_cmd_atomic(cmd);
 	int flags;
 	struct scst_tgt_dev *tgt_dev = cmd->tgt_dev;
-	static int ll;
 
 	TRACE_ENTRY();
 
@@ -4465,40 +4464,23 @@ int scst_alloc_space(struct scst_cmd *cm
 		flags |= SGV_POOL_ALLOC_NO_CACHED;
 
 	cmd->sg = sgv_pool_alloc(tgt_dev->pool, cmd->bufflen, gfp_mask, flags,
-			&cmd->sg_cnt, &cmd->sgv, &cmd->dev->dev_mem_lim, NULL);
+			&cmd->sg_cnt, &cmd->sgv, &cmd->dev->dev_mem_lim, NULL,
+			tgt_dev->max_sg_cnt);
 	if (cmd->sg == NULL)
 		goto out;
 
-	if (unlikely(cmd->sg_cnt > tgt_dev->max_sg_cnt)) {
-		if ((ll < 10) || TRACING_MINOR()) {
-			PRINT_INFO("Unable to complete command due to "
-				"SG IO count limitation (requested %d, "
-				"available %d, tgt lim %d)", cmd->sg_cnt,
-				tgt_dev->max_sg_cnt, cmd->tgt->sg_tablesize);
-			ll++;
-		}
-		goto out_sg_free;
-	}
+	EXTRACHECKS_BUG_ON(cmd->sg_cnt > tgt_dev->max_sg_cnt);
 
 	if (cmd->data_direction != SCST_DATA_BIDI)
 		goto success;
 
 	cmd->out_sg = sgv_pool_alloc(tgt_dev->pool, cmd->out_bufflen, gfp_mask,
 			 flags, &cmd->out_sg_cnt, &cmd->out_sgv,
-			 &cmd->dev->dev_mem_lim, NULL);
+			 &cmd->dev->dev_mem_lim, NULL, tgt_dev->max_sg_cnt);
 	if (cmd->out_sg == NULL)
 		goto out_sg_free;
 
-	if (unlikely(cmd->out_sg_cnt > tgt_dev->max_sg_cnt)) {
-		if ((ll < 10) || TRACING_MINOR()) {
-			PRINT_INFO("Unable to complete command due to "
-				"SG IO count limitation (OUT buffer, requested "
-				"%d, available %d, tgt lim %d)", cmd->out_sg_cnt,
-				tgt_dev->max_sg_cnt, cmd->tgt->sg_tablesize);
-			ll++;
-		}
-		goto out_out_sg_free;
-	}
+	EXTRACHECKS_BUG_ON(cmd->out_sg_cnt > tgt_dev->max_sg_cnt);
 
 success:
 	res = 0;
@@ -4507,12 +4489,6 @@ out:
 	TRACE_EXIT();
 	return res;
 
-out_out_sg_free:
-	sgv_pool_free(cmd->out_sgv, &cmd->dev->dev_mem_lim);
-	cmd->out_sgv = NULL;
-	cmd->out_sg = NULL;
-	cmd->out_sg_cnt = 0;
-
 out_sg_free:
 	sgv_pool_free(cmd->sgv, &cmd->dev->dev_mem_lim);
 	cmd->sgv = NULL;
Index: scst/src/scst_mem.c
===================================================================
--- scst/src/scst_mem.c	(revision 3134)
+++ scst/src/scst_mem.c	(working copy)
@@ -110,8 +110,8 @@ static void sgv_dtor_and_free(struct sgv
 	TRACE_MEM("Destroying sgv obj %p", obj);
 
 	if (obj->sg_count != 0) {
-		pool->alloc_fns.free_pages_fn(obj->sg_entries,
-			obj->sg_count, obj->allocator_priv);
+		pool->alloc_fns.free_pages_fn(obj->sg_entries, obj->sg_count,
+			obj->alloc_order, obj->allocator_priv);
 	}
 	if (obj->sg_entries != obj->sg_entries_data) {
 		if (obj->trans_tbl !=
@@ -522,11 +522,13 @@ out:
 }
 
 static void sgv_free_sys_sg_entries(struct scatterlist *sg, int sg_count,
-	void *priv)
+	int alloc_order, void *priv)
 {
 	int i;
+	const int num_pages = 1 << alloc_order;
 
-	TRACE_MEM("sg=%p, sg_count=%d", sg, sg_count);
+	TRACE_MEM("sg=%p, sg_count=%d, alloc_order=%d",
+		  sg, sg_count, alloc_order);
 
 	for (i = 0; i < sg_count; i++) {
 		struct page *p = sg_page(&sg[i]);
@@ -538,36 +540,23 @@ static void sgv_free_sys_sg_entries(stru
 			(unsigned long)p, len, pages);
 
 		while (pages > 0) {
-			int order = 0;
-
-/*
- * __free_pages() doesn't like freeing pages with not that order with
- * which they were allocated, so disable this small optimization.
- */
-#if 0
-			if (len > 0) {
-				while (((1 << order) << PAGE_SHIFT) < len)
-					order++;
-				len = 0;
-			}
-#endif
 			TRACE_MEM("free_pages(): order %d, page %lx",
-				order, (unsigned long)p);
+				  alloc_order, (unsigned long)p);
 
-			__free_pages(p, order);
+			__free_pages(p, alloc_order);
 
-			pages -= 1 << order;
-			p += 1 << order;
+			pages -= num_pages;
+			p += num_pages;
 		}
 	}
 }
 
-static struct page *sgv_alloc_sys_pages(struct scatterlist *sg,
-	gfp_t gfp_mask, void *priv)
+static struct page *sgv_alloc_sys_pages(struct scatterlist *sg, gfp_t gfp_mask,
+	int alloc_order, void *priv)
 {
-	struct page *page = alloc_pages(gfp_mask, 0);
+	struct page *page = alloc_pages(gfp_mask, alloc_order);
 
-	sg_set_page(sg, page, PAGE_SIZE, 0);
+	sg_set_page(sg, page, PAGE_SIZE << alloc_order, 0);
 	TRACE_MEM("page=%p, sg=%p, priv=%p", page, sg, priv);
 	if (page == NULL) {
 		TRACE(TRACE_OUT_OF_MEM, "%s", "Allocation of "
@@ -579,7 +568,7 @@ static struct page *sgv_alloc_sys_pages(
 static int sgv_alloc_sg_entries(struct scatterlist *sg, int pages,
 	gfp_t gfp_mask, enum sgv_clustering_types clustering_type,
 	struct trans_tbl_ent *trans_tbl,
-	const struct sgv_pool_alloc_fns *alloc_fns, void *priv)
+	const struct sgv_pool_alloc_fns *alloc_fns, int alloc_order, void *priv)
 {
 	int sg_count = 0;
 	int pg, i, j;
@@ -594,7 +583,7 @@ static int sgv_alloc_sg_entries(struct s
 	gfp_mask |= __GFP_ZERO;
 #endif
 
-	for (pg = 0; pg < pages; pg++) {
+	for (pg = 0; pg < pages; pg += 1 << alloc_order) {
 		void *rc;
 #ifdef CONFIG_SCST_DEBUG_OOM
 		if (((gfp_mask & __GFP_NOFAIL) != __GFP_NOFAIL) &&
@@ -603,7 +592,7 @@ static int sgv_alloc_sg_entries(struct s
 		else
 #endif
 			rc = alloc_fns->alloc_pages_fn(&sg[sg_count], gfp_mask,
-				priv);
+				alloc_order, priv);
 		if (rc == NULL)
 			goto out_no_mem;
 
@@ -623,8 +612,8 @@ static int sgv_alloc_sg_entries(struct s
 		if (merged == -1)
 			sg_count++;
 
-		TRACE_MEM("pg=%d, merged=%d, sg_count=%d", pg, merged,
-			sg_count);
+		TRACE_MEM("pg=%d, merged=%d, sg_count=%d",
+			pg, merged, sg_count);
 	}
 
 	if ((clustering_type != sgv_no_clustering) && (trans_tbl != NULL)) {
@@ -645,7 +634,7 @@ out:
 	return sg_count;
 
 out_no_mem:
-	alloc_fns->free_pages_fn(sg, sg_count, priv);
+	alloc_fns->free_pages_fn(sg, sg_count, alloc_order, priv);
 	sg_count = 0;
 	goto out;
 }
@@ -704,32 +693,16 @@ out_free:
 	goto out;
 }
 
-static struct sgv_pool_obj *sgv_get_obj(struct sgv_pool *pool, int cache_num,
-	int pages, gfp_t gfp_mask, bool get_new)
+static struct sgv_pool_obj *sgv_create_obj(struct sgv_pool *pool,
+	int cache_num,
+	int pages, gfp_t gfp_mask,
+	int locked)
 {
 	struct sgv_pool_obj *obj;
 
-	spin_lock_bh(&pool->sgv_pool_lock);
-
-	if (unlikely(get_new)) {
-		/* Used only for buffers preallocation */
-		goto get_new;
-	}
-
-	if (likely(!list_empty(&pool->recycling_lists[cache_num]))) {
-		obj = list_entry(pool->recycling_lists[cache_num].next,
-			 struct sgv_pool_obj, recycling_list_entry);
-
-		list_del(&obj->sorted_recycling_list_entry);
-		list_del(&obj->recycling_list_entry);
-
-		pool->inactive_cached_pages -= pages;
-
-		spin_unlock_bh(&pool->sgv_pool_lock);
-		goto out;
-	}
+	if (!locked)
+		spin_lock_bh(&pool->sgv_pool_lock);
 
-get_new:
 	if (pool->cached_entries == 0) {
 		TRACE_MEM("Adding pool %p to the active list", pool);
 		spin_lock_bh(&sgv_pools_lock);
@@ -759,6 +732,57 @@ get_new:
 		spin_unlock_bh(&pool->sgv_pool_lock);
 	}
 
+	return obj;
+}
+
+/* FZ Notes: cache_num == order, and we should have pages = 1 << cache_num. */
+static struct sgv_pool_obj *sgv_get_obj(struct sgv_pool *pool, int cache_num,
+	int pages, gfp_t gfp_mask,
+	int max_sg_count, bool get_new)
+{
+	struct sgv_pool_obj *obj;
+
+	spin_lock_bh(&pool->sgv_pool_lock);
+
+	if (unlikely(get_new)) {
+		/* Used only for buffers preallocation */
+		/* TODO: caller of that should now call
+		 * sgv_create_obj, and this will go away. */
+		goto get_new;
+	}
+
+	if (likely(!list_empty(&pool->recycling_lists[cache_num]))) {
+		list_for_each_entry(obj, &pool->recycling_lists[cache_num],
+				    recycling_list_entry) {
+
+			TRACE_MEM("obj %p, sg_count %d (max %d)", obj,
+				  obj->sg_count, max_sg_count);
+
+			if (unlikely(obj->sg_count > max_sg_count))
+				continue;
+
+			obj = list_entry(pool->recycling_lists[cache_num].next,
+					 struct sgv_pool_obj,
+					 recycling_list_entry);
+
+			list_del(&obj->sorted_recycling_list_entry);
+			list_del(&obj->recycling_list_entry);
+
+			pool->inactive_cached_pages -= pages;
+
+			spin_unlock_bh(&pool->sgv_pool_lock);
+
+			/* FZ: note entirely sure of that check. Need
+			 * to investigate. */
+			/*EXTRACHECKS_BUG_ON(obj->alloc_order <= cache_num);*/
+
+			goto out;
+		}
+	}
+
+get_new:
+	obj = sgv_create_obj(pool, cache_num, pages, gfp_mask, true);
+
 out:
 	return obj;
 }
@@ -908,14 +932,17 @@ static void sgv_uncheck_allowed_mem(stru
  */
 struct scatterlist *sgv_pool_alloc(struct sgv_pool *pool, unsigned int size,
 	gfp_t gfp_mask, int flags, int *count,
-	struct sgv_pool_obj **sgv, struct scst_mem_lim *mem_lim, void *priv)
+	struct sgv_pool_obj **sgv, struct scst_mem_lim *mem_lim, void *priv,
+	int max_sg_count)
 {
 	struct sgv_pool_obj *obj;
 	int cache_num, pages, cnt;
 	struct scatterlist *res = NULL;
 	int pages_to_alloc;
+	int alloc_order;
 	int no_cached = flags & SGV_POOL_ALLOC_NO_CACHED;
 	bool allowed_mem_checked = false, hiwmk_checked = false;
+	int tmp;
 
 	TRACE_ENTRY();
 
@@ -958,7 +985,7 @@ struct scatterlist *sgv_pool_alloc(struc
 		allowed_mem_checked = true;
 
 		obj = sgv_get_obj(pool, cache_num, pages_to_alloc, gfp_mask,
-			flags & SGV_POOL_ALLOC_GET_NEW);
+			max_sg_count, flags & SGV_POOL_ALLOC_GET_NEW);
 		if (unlikely(obj == NULL)) {
 			TRACE(TRACE_OUT_OF_MEM, "Allocation of "
 				"sgv_pool_obj failed (size %d)", size);
@@ -967,7 +994,30 @@ struct scatterlist *sgv_pool_alloc(struc
 
 		if (obj->sg_count != 0) {
 			TRACE_MEM("Cached obj %p", obj);
-			atomic_inc(&pool->cache_acc[cache_num].hit_alloc);
+
+			if (unlikely(max_sg_count < obj->sg_count)) {
+				TRACE_MEM("Too many SG entries %d (max %d)",
+					  obj->sg_count, max_sg_count);
+
+				sgv_put_obj(obj);
+
+				obj = sgv_create_obj(pool, cache_num,
+						     pages_to_alloc, gfp_mask,
+						     false);
+				if (obj &&
+				    unlikely(max_sg_count < obj->sg_count)) {
+					sgv_put_obj(obj);
+					obj = NULL;
+				}
+
+				if (obj == NULL) {
+					TRACE(TRACE_OUT_OF_MEM, "Allocation of "
+					      "sgv_pool_obj failed (size %d)",
+					      size);
+					goto out_fail;
+				}
+			} else
+				atomic_inc(&pool->cache_acc[cache_num].hit_alloc);
 			goto success;
 		}
 
@@ -1045,16 +1095,44 @@ struct scatterlist *sgv_pool_alloc(struc
 		TRACE_MEM("Big or no_cached obj %p (size %d)", obj, sz);
 	}
 
-	obj->sg_count = sgv_alloc_sg_entries(obj->sg_entries,
-		pages_to_alloc, gfp_mask, pool->clustering_type,
-		obj->trans_tbl, &pool->alloc_fns, priv);
-	if (unlikely(obj->sg_count <= 0)) {
-		obj->sg_count = 0;
-		if ((flags & SGV_POOL_RETURN_OBJ_ON_ALLOC_FAIL) &&
-		    (cache_num >= 0))
-			goto out_return1;
-		else
-			goto out_fail_free_sg_entries;
+	/* Allocate the scatter gather entries. Since the memory we
+	 * request may fit in too many entries, we try to start with
+	 * an order big enough. That will save some useless
+	 * allocations. */
+	alloc_order = 0;
+	tmp = pages_to_alloc;
+	while (tmp > max_sg_count) {
+		tmp >>= 1;
+		alloc_order++;
+	}
+
+	while (1) {
+		obj->sg_count = sgv_alloc_sg_entries(obj->sg_entries,
+						     pages_to_alloc,
+						     gfp_mask,
+						     pool->clustering_type,
+						     obj->trans_tbl,
+						     &pool->alloc_fns,
+						     alloc_order, priv);
+		if (unlikely(obj->sg_count <= 0)) {
+			obj->sg_count = 0;
+			if ((flags & SGV_POOL_RETURN_OBJ_ON_ALLOC_FAIL) &&
+			    (cache_num >= 0))
+				goto out_return1;
+			else
+				goto out_fail_free_sg_entries;
+		}
+
+		obj->alloc_order = alloc_order;
+
+		if (likely(obj->sg_count <= max_sg_count))
+			break;
+
+		obj->owner_pool->alloc_fns.free_pages_fn(obj->sg_entries,
+							 obj->sg_count,
+							 obj->alloc_order,
+							 obj->allocator_priv);
+		alloc_order++;
 	}
 
 	if (cache_num >= 0) {
@@ -1230,7 +1308,7 @@ void sgv_pool_free(struct sgv_pool_obj *
 		sgv_put_obj(obj);
 	} else {
 		obj->owner_pool->alloc_fns.free_pages_fn(obj->sg_entries,
-			obj->sg_count, obj->allocator_priv);
+			obj->sg_count, obj->alloc_order, obj->allocator_priv);
 		kfree(obj);
 		sgv_hiwmk_uncheck(pages);
 	}
@@ -1289,7 +1367,7 @@ struct scatterlist *scst_alloc(int size,
 	 * So, let's always don't use clustering.
 	 */
 	cnt = sgv_alloc_sg_entries(res, pages, gfp_mask, sgv_no_clustering,
-			NULL, &sys_alloc_fns, NULL);
+			NULL, &sys_alloc_fns, 0, NULL);
 	if (cnt <= 0)
 		goto out_free;
 
@@ -1326,7 +1404,7 @@ void scst_free(struct scatterlist *sg, i
 
 	sgv_hiwmk_uncheck(count);
 
-	sgv_free_sys_sg_entries(sg, count, NULL);
+	sgv_free_sys_sg_entries(sg, count, 0, NULL);
 	kfree(sg);
 	return;
 }
@@ -1580,8 +1658,9 @@ static void sgv_pool_destroy(struct sgv_
  *    See the SGV pool documentation for more details.
  */
 void sgv_pool_set_allocator(struct sgv_pool *pool,
-	struct page *(*alloc_pages_fn)(struct scatterlist *, gfp_t, void *),
-	void (*free_pages_fn)(struct scatterlist *, int, void *))
+	struct page *(*alloc_pages_fn)(struct scatterlist *, gfp_t,
+				       int, void *),
+	void (*free_pages_fn)(struct scatterlist *, int, int, void *))
 {
 	pool->alloc_fns.alloc_pages_fn = alloc_pages_fn;
 	pool->alloc_fns.free_pages_fn = free_pages_fn;
Index: scst/src/dev_handlers/scst_user.c
===================================================================
--- scst/src/dev_handlers/scst_user.c	(revision 3134)
+++ scst/src/dev_handlers/scst_user.c	(working copy)
@@ -163,9 +163,9 @@ static int dev_user_disk_done(struct scs
 static int dev_user_tape_done(struct scst_cmd *cmd);
 
 static struct page *dev_user_alloc_pages(struct scatterlist *sg,
-	gfp_t gfp_mask, void *priv);
+	gfp_t gfp_mask, int alloc_order, void *priv);
 static void dev_user_free_sg_entries(struct scatterlist *sg, int sg_count,
-				     void *priv);
+	int alloc_order, void *priv);
 
 static void dev_user_add_to_ready(struct scst_user_cmd *ucmd);
 
@@ -392,7 +392,7 @@ static void dev_user_free_ucmd(struct sc
 }
 
 static struct page *dev_user_alloc_pages(struct scatterlist *sg,
-	gfp_t gfp_mask, void *priv)
+	gfp_t gfp_mask, int alloc_order, void *priv)
 {
 	struct scst_user_cmd *ucmd = (struct scst_user_cmd *)priv;
 	int offset = 0;
@@ -401,8 +401,11 @@ static struct page *dev_user_alloc_pages
 
 	/* *sg supposed to be zeroed */
 
-	TRACE_MEM("ucmd %p, ubuff %lx, ucmd->cur_data_page %d", ucmd,
-		ucmd->ubuff, ucmd->cur_data_page);
+	TRACE_MEM("ucmd %p, ubuff %lx, ucmd->cur_data_page %d, alloc_order %d",
+		ucmd, ucmd->ubuff, ucmd->cur_data_page, alloc_order);
+
+	if (unlikely(alloc_order != 0))
+		goto out;
 
 	if (ucmd->cur_data_page == 0) {
 		TRACE_MEM("ucmd->first_page_offset %d",
@@ -495,7 +498,7 @@ static void __dev_user_free_sg_entries(s
 }
 
 static void dev_user_free_sg_entries(struct scatterlist *sg, int sg_count,
-	void *priv)
+	int alloc_order, void *priv)
 {
 	struct scst_user_cmd *ucmd = (struct scst_user_cmd *)priv;
 
@@ -582,7 +585,8 @@ static int dev_user_alloc_sg(struct scst
 	ucmd->buff_cached = cached_buff;
 
 	cmd->sg = sgv_pool_alloc(pool, bufflen, gfp_mask, flags, &cmd->sg_cnt,
-			&ucmd->sgv, &dev->udev_mem_lim, ucmd);
+			&ucmd->sgv, &dev->udev_mem_lim, ucmd,
+			cmd->tgt_dev->max_sg_cnt);
 	if (cmd->sg != NULL) {
 		struct scst_user_cmd *buf_ucmd =
 			(struct scst_user_cmd *)sgv_get_priv(ucmd->sgv);
@@ -614,20 +618,7 @@ static int dev_user_alloc_sg(struct scst
 				cmd, cmd->out_sg, cmd->out_sg_cnt, cmd->sg_cnt);
 		}
 
-		if (unlikely(cmd->sg_cnt > cmd->tgt_dev->max_sg_cnt)) {
-			static int ll;
-			if ((ll < 10) || TRACING_MINOR()) {
-				PRINT_INFO("Unable to complete command due to "
-					"SG IO count limitation (requested %d, "
-					"available %d, tgt lim %d)",
-					cmd->sg_cnt, cmd->tgt_dev->max_sg_cnt,
-					cmd->tgt->sg_tablesize);
-				ll++;
-			}
-			cmd->sg = NULL;
-			/* sgv will be freed in dev_user_free_sgv() */
-			res = -1;
-		}
+		EXTRACHECKS_BUG_ON(cmd->sg_cnt > cmd->tgt_dev->max_sg_cnt);
 	} else {
 		TRACE_MEM("Buf not alloced (ucmd %p, h %d, buff_cached, %d, "
 			"sg_cnt %d, ubuff %lx, sgv %p", ucmd, ucmd->h,
@@ -3137,6 +3128,14 @@ static int dev_user_prealloc_buffer(stru
 
 	TRACE_ENTRY();
 
+	{
+		/* The SGV patch cannot support that feature because
+		 * we don't know either the target or the number of SG
+		 * buffer of the target. */
+		res = -EINVAL;
+		goto out;
+	}
+
 	mutex_lock(&dev_priv_mutex);
 	dev = (struct scst_user_dev *)file->private_data;
 	res = dev_user_check_reg(dev);
@@ -3188,7 +3187,7 @@ static int dev_user_prealloc_buffer(stru
 		pool = dev->pool;
 
 	sg = sgv_pool_alloc(pool, bufflen, GFP_KERNEL, SGV_POOL_ALLOC_GET_NEW,
-			 &sg_cnt, &ucmd->sgv, &dev->udev_mem_lim, ucmd);
+			 &sg_cnt, &ucmd->sgv, &dev->udev_mem_lim, ucmd, 0);
 	if (sg != NULL) {
 		struct scst_user_cmd *buf_ucmd =
 			(struct scst_user_cmd *)sgv_get_priv(ucmd->sgv);