Controllers that support DMA of protection information must be told
explicitly how to handle the I/O. The controller has no knowledge of
the protection capabilities of the target device so this information
must be passed in the scsi_cmnd.
The protection operation tells the HBA whether to generate, strip or
verify protection information.
When a scsi_cmnd is reused for error handling, the protection
operation must be cleared and saved while error handling is in
progress.
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
---
3 files changed, 32 insertions(+)
drivers/scsi/scsi_error.c | 3 +++
include/scsi/scsi_cmnd.h | 28 ++++++++++++++++++++++++++++
include/scsi/scsi_eh.h | 1 +
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -653,7 +653,9 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd
ses->sdb = scmd->sdb;
ses->next_rq = scmd->request->next_rq;
ses->result = scmd->result;
+ ses->prot_op = scmd->prot_op;
+ scmd->prot_op = SCSI_PROT_NORMAL;
scmd->cmnd = ses->eh_cmnd;
memset(scmd->cmnd, 0, BLK_MAX_CDB);
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
@@ -711,6 +713,7 @@ void scsi_eh_restore_cmnd(struct scsi_cm
scmd->sdb = ses->sdb;
scmd->request->next_rq = ses->next_rq;
scmd->result = ses->result;
+ scmd->prot_op = ses->prot_op;
}
EXPORT_SYMBOL(scsi_eh_restore_cmnd);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -77,6 +77,8 @@ struct scsi_cmnd {
int retries;
int allowed;
int timeout_per_command;
+
+ unsigned char prot_op;
unsigned short cmd_len;
enum dma_data_direction sc_data_direction;
@@ -211,6 +213,32 @@ static inline int scsi_sg_copy_to_buffer
buf, buflen);
}
+/*
+ * The operations below are hints that tell the controller driver how
+ * to handle I/Os with DIF or similar types of protection information.
+ */
+
+enum scsi_prot_operations {
+ /* Normal I/O */
+ SCSI_PROT_NORMAL = 0,
+
+ /* OS-HBA: Protected, HBA-Target: Unprotected */
+ SCSI_PROT_READ_INSERT,
+ SCSI_PROT_WRITE_STRIP,
+
+ /* OS-HBA: Unprotected, HBA-Target: Protected */
+ SCSI_PROT_READ_STRIP,
+ SCSI_PROT_WRITE_INSERT,
+
+ /* OS-HBA: Protected, HBA-Target: Protected */
+ SCSI_PROT_READ_PASS,
+ SCSI_PROT_WRITE_PASS,
+
+ /* OS-HBA: Protected, HBA-Target: Protected, checksum conversion */
+ SCSI_PROT_READ_CONVERT,
+ SCSI_PROT_WRITE_CONVERT,
+};
+
static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd)
{
return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0;
diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -75,6 +75,7 @@ struct scsi_eh_save {
int result;
enum dma_data_direction data_direction;
unsigned char cmd_len;
+ unsigned char prot_op;
unsigned char *cmnd;
struct scsi_data_buffer sdb;
struct request *next_rq;
--
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