target: split overflow and underflow checks into a helper

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

1 files changed, 53 insertions, 37 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a181951a7aca..23657a027666 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1345,6 +1345,55 @@ static inline void transport_generic_prepare_cdb(
 
 static int transport_generic_cmd_sequencer(struct se_cmd *, unsigned char *);
 
+static int target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
+{
+        struct se_device *dev = cmd->se_dev;
+
+        if (cmd->unknown_data_length) {
+                cmd->data_length = size;
+        } else if (size != cmd->data_length) {
+                pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
+                        " %u does not match SCSI CDB Length: %u for SAM Opcode:"
+                        " 0x%02x\n", cmd->se_tfo->get_fabric_name(),
+                                cmd->data_length, size, cmd->t_task_cdb[0]);
+
+                cmd->cmd_spdtl = size;
+
+                if (cmd->data_direction == DMA_TO_DEVICE) {
+                        pr_err("Rejecting underflow/overflow"
+                                        " WRITE data\n");
+                        goto out_invalid_cdb_field;
+                }
+                /*
+                 * Reject READ_* or WRITE_* with overflow/underflow for
+                 * type SCF_SCSI_DATA_CDB.
+                 */
+                if (dev->se_sub_dev->se_dev_attrib.block_size != 512)  {
+                        pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
+                                " CDB on non 512-byte sector setup subsystem"
+                                " plugin: %s\n", dev->transport->name);
+                        /* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
+                        goto out_invalid_cdb_field;
+                }
+
+                if (size > cmd->data_length) {
+                        cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
+                        cmd->residual_count = (size - cmd->data_length);
+                } else {
+                        cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
+                        cmd->residual_count = (cmd->data_length - size);
+                }
+                cmd->data_length = size;
+        }
+
+        return 0;
+
+out_invalid_cdb_field:
+        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+        cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+        return -EINVAL;
+}
+
 /*
  * Used by fabric modules containing a local struct se_cmd within their
  * fabric dependent per I/O descriptor.
@@ -2431,6 +2480,7 @@ static int transport_generic_cmd_sequencer(
         int sector_ret = 0, passthrough;
         u32 sectors = 0, size = 0;
         u16 service_action;
+        int ret;
 
         /*
          * If we operate in passthrough mode we skip most CDB emulation and
@@ -2929,43 +2979,9 @@ static int transport_generic_cmd_sequencer(
                 goto out_unsupported_cdb;
         }
 
-        if (cmd->unknown_data_length)
-                cmd->data_length = size;
-
-        if (size != cmd->data_length) {
-                pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
-                        " %u does not match SCSI CDB Length: %u for SAM Opcode:"
-                        " 0x%02x\n", cmd->se_tfo->get_fabric_name(),
-                                cmd->data_length, size, cdb[0]);
-
-                cmd->cmd_spdtl = size;
-
-                if (cmd->data_direction == DMA_TO_DEVICE) {
-                        pr_err("Rejecting underflow/overflow"
-                                        " WRITE data\n");
-                        goto out_invalid_cdb_field;
-                }
-                /*
-                 * Reject READ_* or WRITE_* with overflow/underflow for
-                 * type SCF_SCSI_DATA_CDB.
-                 */
-                if (dev->se_sub_dev->se_dev_attrib.block_size != 512)  {
-                        pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
-                                " CDB on non 512-byte sector setup subsystem"
-                                " plugin: %s\n", dev->transport->name);
-                        /* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
-                        goto out_invalid_cdb_field;
-                }
-
-                if (size > cmd->data_length) {
-                        cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
-                        cmd->residual_count = (size - cmd->data_length);
-                } else {
-                        cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
-                        cmd->residual_count = (cmd->data_length - size);
-                }
-                cmd->data_length = size;
-        }
+        ret = target_cmd_size_check(cmd, size);
+        if (ret)
+                return ret;
 
         if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
                 if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {