target: Add target_submit_cmd_map_sgls for SGL fabric memory passthrough

This patch adds a new target_submit_cmd_map_sgls() to pass pre-allocated
SGL memory using transport_generic_map_mem_to_cmd() logic into the generic
target submit I/O codepath.

It also adds a target_submit_cmd() wrapper around target_submit_cmd_map_sgls()
for existing fabric code that already assumes internal target-core SGL memory
allocation.

(v2: Rename to target_submit_cmd_map_sgls + drop TARGET_SCF_MAP_MEM flag
     in favor of non zero sgl_count check)

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 85a5d7a99543..81ddb4ae6c3f 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -100,6 +100,9 @@ void	transport_init_se_cmd(struct se_cmd *, struct target_core_fabric_ops *,
                 struct se_session *, u32, int, int, unsigned char *);
 int     transport_lookup_cmd_lun(struct se_cmd *, u32);
 int     target_setup_cmd_from_cdb(struct se_cmd *, unsigned char *);
+int     target_submit_cmd_map_sgls(struct se_cmd *, struct se_session *,
+                unsigned char *, unsigned char *, u32, u32, int, int, int,
+                struct scatterlist *, u32, struct scatterlist *, u32);
 int     target_submit_cmd(struct se_cmd *, struct se_session *, unsigned char *,
                 unsigned char *, u32, u32, int, int, int);
 int     target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,