target: enhance and export target_alloc_sgl/target_free_sgl

The SRP target driver will need to allocate and chain it's own SGLs soon.
For this export target_alloc_sgl, and add a new argument to it so that it
can allocate an additional chain entry that doesn't point to a page.  Also
export transport_free_sgl after renaming it to target_free_sgl to free
these SGLs again.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

2 files changed, 4 insertions, 1 deletions

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 28ee5c2e6bcd..d8ab5101fad5 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -85,7 +85,6 @@ extern struct configfs_attribute *passthrough_attrib_attrs[];
 void    *transport_kmap_data_sg(struct se_cmd *);
 void    transport_kunmap_data_sg(struct se_cmd *);
 /* core helpers also used by xcopy during internal command setup */
-int     target_alloc_sgl(struct scatterlist **, unsigned int *, u32, bool);
 sense_reason_t  transport_generic_map_mem_to_cmd(struct se_cmd *,
                 struct scatterlist *, u32, struct scatterlist *, u32);
 
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 8ff6d40a294f..78d88f03b296 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -185,6 +185,10 @@ int	core_tpg_set_initiator_node_tag(struct se_portal_group *,
 int     core_tpg_register(struct se_wwn *, struct se_portal_group *, int);
 int     core_tpg_deregister(struct se_portal_group *);
 
+int     target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
+                u32 length, bool zero_page, bool chainable);
+void    target_free_sgl(struct scatterlist *sgl, int nents);
+
 /*
  * The LIO target core uses DMA_TO_DEVICE to mean that data is going
  * to the target (eg handling a WRITE) and DMA_FROM_DEVICE to mean