From: Aleksandr Miloserdov <a.miloserdov@xxxxxxxxx> [ Upstream commit 1c73e0c5e54d5f7d77f422a10b03ebe61eaed5ad ] 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@xxxxxxxxx Reviewed-by: Roman Bolshakov <r.bolshakov@xxxxxxxxx> Reviewed-by: Bodo Stroesser <bostroesser@xxxxxxxxx> Signed-off-by: Aleksandr Miloserdov <a.miloserdov@xxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/target/target_core_transport.c | 15 +++++++++++---- include/target/target_core_backend.h | 1 + 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index f1b730b77a31..bdada97cd4fe 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -841,11 +841,9 @@ 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 { @@ -855,6 +853,15 @@ 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); } diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h index 51b6f50eabee..0deeff9b4496 100644 --- a/include/target/target_core_backend.h +++ b/include/target/target_core_backend.h @@ -69,6 +69,7 @@ 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 *); -- 2.30.1
