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>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a181951..23657a0 100644 (file)
--- 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) {