Add a max_cmd_len field to the scsi_device struct
to allow for per device limits of allowable command
lengths. This patch was submitted earlier and resulted
in a bit of discussion regarding whether or not
CDB length is a limitation of the host or the device.
For ATA, both the host and the device can limit the
CDB length. Currently libata reads the IDENTIFY
PACKET DEVICE data for an ATAPI device and sets
the max_cmd_len in the scsi host for the maximum
supported CDB length of all ATA/ATAPI devices attached
to the same scsi host. This patch allows libata to
set the max CDB length on a per device basis and
allows the SAS/SATA HBA to set its own max command
length in the scsi host template.
Signed-off-by: Brian King <brking@xxxxxxxxxx>
---
libata-dev-bjking1/drivers/scsi/scsi.c | 3 ++-
libata-dev-bjking1/drivers/scsi/scsi_scan.c | 1 +
libata-dev-bjking1/include/scsi/scsi_device.h | 1 +
3 files changed, 4 insertions(+), 1 deletion(-)
diff -puN include/scsi/scsi_device.h~scsi_device_cdb_len include/scsi/scsi_device.h
--- libata-dev/include/scsi/scsi_device.h~scsi_device_cdb_len 2006-04-17 17:17:50.000000000 -0500
+++ libata-dev-bjking1/include/scsi/scsi_device.h 2006-04-17 17:17:50.000000000 -0500
@@ -72,6 +72,7 @@ struct scsi_device {
unsigned int manufacturer; /* Manufacturer of device, for using
* vendor-specific cmd's */
unsigned sector_size; /* size in bytes */
+ unsigned char max_cmd_len;
void *hostdata; /* available to low-level driver */
char type;
diff -puN drivers/scsi/scsi_scan.c~scsi_device_cdb_len drivers/scsi/scsi_scan.c
--- libata-dev/drivers/scsi/scsi_scan.c~scsi_device_cdb_len 2006-04-17 17:17:50.000000000 -0500
+++ libata-dev-bjking1/drivers/scsi/scsi_scan.c 2006-04-17 17:17:50.000000000 -0500
@@ -218,6 +218,7 @@ static struct scsi_device *scsi_alloc_sd
sdev->lun = lun;
sdev->channel = starget->channel;
sdev->sdev_state = SDEV_CREATED;
+ sdev->max_cmd_len = MAX_COMMAND_SIZE;
INIT_LIST_HEAD(&sdev->siblings);
INIT_LIST_HEAD(&sdev->same_target_siblings);
INIT_LIST_HEAD(&sdev->cmd_list);
diff -puN drivers/scsi/scsi.c~scsi_device_cdb_len drivers/scsi/scsi.c
--- libata-dev/drivers/scsi/scsi.c~scsi_device_cdb_len 2006-04-17 17:17:50.000000000 -0500
+++ libata-dev-bjking1/drivers/scsi/scsi.c 2006-04-17 17:17:50.000000000 -0500
@@ -610,7 +610,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *
* Before we queue this command, check if the command
* length exceeds what the host adapter can handle.
*/
- if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
+ if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len ||
+ CDB_SIZE(cmd) > cmd->device->max_cmd_len) {
SCSI_LOG_MLQUEUE(3,
printk("queuecommand : command too long.\n"));
cmd->result = (DID_ABORT << 16);
_
-
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