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Commit 7abc17dc authored by Aleksandr Miloserdov's avatar Aleksandr Miloserdov Committed by Greg Kroah-Hartman
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scsi: target: core: Add cmd length set before cmd complete 

[ 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@yadro.com


Reviewed-by: default avatarRoman Bolshakov <r.bolshakov@yadro.com>
Reviewed-by: default avatarBodo Stroesser <bostroesser@gmail.com>
Signed-off-by: default avatarAleksandr Miloserdov <a.miloserdov@yadro.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 1e1749c5

drivers/target/target_core_transport.c

+11 −4
Original line number Diff line number Diff line
@@ -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);

}

include/target/target_core_backend.h

+1 −0
Original line number Diff line number Diff line
@@ -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 *);