scsi: target: core: Add cmd length set before cmd complete

TCM doesn't properly handle underflow case for service actions. One way to
prevent it is to always complete command with
target_complete_cmd_with_length(), however it requires access to data_sg,
which is not always available.

This change introduces target_set_cmd_data_length() function which allows
to set command data length before completing it.

Link: https://lore.kernel.org/r/20210209072202.41154-2-a.miloserdov@yadro.com
Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Aleksandr Miloserdov <a.miloserdov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Aleksandr Miloserdov 2021-02-09 10:22:01 +03:00 committed by Martin K. Petersen
parent d39bfd0686
commit 1c73e0c5e5
2 changed files with 12 additions and 4 deletions

View File

@ -879,11 +879,9 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
}
EXPORT_SYMBOL(target_complete_cmd);
void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
void target_set_cmd_data_length(struct se_cmd *cmd, int length)
{
if ((scsi_status == SAM_STAT_GOOD ||
cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
length < cmd->data_length) {
if (length < cmd->data_length) {
if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
cmd->residual_count += cmd->data_length - length;
} else {
@ -893,6 +891,15 @@ void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int len
cmd->data_length = length;
}
}
EXPORT_SYMBOL(target_set_cmd_data_length);
void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
{
if (scsi_status == SAM_STAT_GOOD ||
cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) {
target_set_cmd_data_length(cmd, length);
}
target_complete_cmd(cmd, scsi_status);
}

View File

@ -72,6 +72,7 @@ int transport_backend_register(const struct target_backend_ops *);
void target_backend_unregister(const struct target_backend_ops *);
void target_complete_cmd(struct se_cmd *, u8);
void target_set_cmd_data_length(struct se_cmd *, int);
void target_complete_cmd_with_length(struct se_cmd *, u8, int);
void transport_copy_sense_to_cmd(struct se_cmd *, unsigned char *);