target: pass sense_reason as a return value

Pass the sense reason as an explicit return value from the I/O submission
path instead of storing it in struct se_cmd and using negative return
values.  This cleans up a lot of the code pathes, and with the sparse
annotations for the new sense_reason_t type allows for much better
error checking.

(nab: Convert spc_emulate_modesense + spc_emulate_modeselect to use
      sense_reason_t with Roland's MODE SELECT changes)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 92b1307a9931..126529cd5325 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -275,7 +275,8 @@ static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 	return NULL;
 }
 
-static int rd_execute_rw(struct se_cmd *cmd)
+static sense_reason_t
+rd_execute_rw(struct se_cmd *cmd)
 {
 	struct scatterlist *sgl = cmd->t_data_sg;
 	u32 sgl_nents = cmd->t_data_nents;
@@ -298,7 +299,7 @@ static int rd_execute_rw(struct se_cmd *cmd)
 
 	table = rd_get_sg_table(dev, rd_page);
 	if (!table)
-		return -EINVAL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 
 	rd_sg = &table->sg_table[rd_page - table->page_start_offset];
 
@@ -348,7 +349,7 @@ static int rd_execute_rw(struct se_cmd *cmd)
 		table = rd_get_sg_table(dev, rd_page);
 		if (!table) {
 			sg_miter_stop(&m);
-			return -EINVAL;
+			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 		}
 
 		/* since we increment, the first sg entry is correct */
@@ -431,7 +432,8 @@ static struct sbc_ops rd_sbc_ops = {
 	.execute_rw		= rd_execute_rw,
 };
 
-static int rd_parse_cdb(struct se_cmd *cmd)
+static sense_reason_t
+rd_parse_cdb(struct se_cmd *cmd)
 {
 	return sbc_parse_cdb(cmd, &rd_sbc_ops);
 }