[PATCH 1/1] cciss: fix error reporting for SG_IO

From: Mike Miller (OS Dev)
Date: Tue Aug 14 2007 - 16:09:03 EST

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Patch 1/1
Steve has been trying to send this out but it doesn't seem to be getting
anywhere. Please review this patch for accuracy. There's a couple of things
not clear to us.

Thanks,
mikem

--------------------------------------------------------------------------------
We found a problem with the way cciss was filling out rq->errors.
Previously, it just put a 1 or a 0 in there and used the negation
of this as the uptodate parameter to one of the functions in the
block layer, being a block device.

For the SG_IO support, this is not sufficient, and we noticed
that for example, sg_turs from sg3_utils does not correctly
detect problems due to cciss filling out rq->errors incorrectly.

So, below is my attempt at fixing this, but I'm not completely
sure I did it all right. It is better than before, in that
now sg_turs seems to detect when things go wrong (e.g.:
when a disk is inaccessible due to cables being yanked, it
notices.)

There is some stuff in scsi.h:

> /*
> * Use these to separate status msg and our bytes
> *
> * These are set by:
> *
> * status byte = set from target device
> * msg_byte = return status from host adapter itself.
> * host_byte = set by low-level driver to indicate status.
> * driver_byte = set by mid-level.
> */
> #define status_byte(result) (((result) >> 1) & 0x7f)
> #define msg_byte(result) (((result) >> 8) & 0xff)
> #define host_byte(result) (((result) >> 16) & 0xff)
> #define driver_byte(result) (((result) >> 24) & 0xff)

I'm unsure about the msg_byte (sg_turs appears not to
look at it.) I used a device specific code (cciss
notion of CommandStatus) here. Not sure if that's correct,
but not sure what else I would use. Any clarification on
that would be helpful. And of course, let me know if you
notice anything else I might have screwed up.

-- steve

Signed-off-by: Stephen M. Cameron <steve.cameron@xxxxxx>

---

drivers/block/cciss.c | 81 ++++++++++++++++++++++++++++++++++++++------------
1 files changed, 63 insertions(+), 18 deletions(-)

diff -puN drivers/block/cciss.c~sg_io_fix_error_reporting drivers/block/cciss.c
--- linux-2.6.23-rc2/drivers/block/cciss.c~sg_io_fix_error_reporting 2007-08-13 09:44:58.000000000 -0500
+++ linux-2.6.23-rc2-scameron/drivers/block/cciss.c 2007-08-13 09:44:58.000000000 -0500
@@ -2366,30 +2366,57 @@ static inline void resend_cciss_cmd(ctlr
start_io(h);
}

+/* inverse of macros in scsi.h */
+
+#define shift_status_byte(x) ((x) & 0xff)
+#define shift_msg_byte(x) (((x) & 0xff) << 8)
+#define shift_host_byte(x) (((x) & 0xff) << 16)
+#define shift_driver_byte(x) (((x) & 0xff) << 24)
+
+#define make_status_bytes(s, m, h, d) \
+ shift_status_byte((s)) |\
+ shift_msg_byte((m)) |\
+ shift_host_byte((h)) |\
+ shift_driver_byte((d))
+
static inline int evaluate_target_status(CommandList_struct *cmd)
{
unsigned char sense_key;
- int error_count = 1;
+ unsigned char status_byte, msg_byte, host_byte, driver_byte;
+ int error_value;
+
+ /* If we get in here, it means we got "target status", that is, scsi status */
+ status_byte = cmd->err_info->ScsiStatus;
+ driver_byte = DRIVER_OK;
+ msg_byte = cmd->err_info->CommandStatus; /* correct? seems too device specific */
+
+ if (blk_pc_request(cmd->rq))
+ host_byte = DID_PASSTHROUGH;
+ else
+ host_byte = DID_OK;
+
+ error_value = make_status_bytes(status_byte, msg_byte,
+ host_byte, driver_byte);

- if (cmd->err_info->ScsiStatus != 0x02) { /* not check condition? */
+ if (cmd->err_info->ScsiStatus != SAM_STAT_CHECK_CONDITION) {
if (!blk_pc_request(cmd->rq))
printk(KERN_WARNING "cciss: cmd %p "
"has SCSI Status 0x%x\n",
cmd, cmd->err_info->ScsiStatus);
- return error_count;
+ return error_value;
}

/* check the sense key */
sense_key = 0xf & cmd->err_info->SenseInfo[2];
/* no status or recovered error */
- if ((sense_key == 0x0) || (sense_key == 0x1))
- error_count = 0;
+ if (((sense_key == 0x0) || (sense_key == 0x1)) && !blk_pc_request(cmd->rq))
+ error_value = 0;

if (!blk_pc_request(cmd->rq)) { /* Not SG_IO or similar? */
- if (error_count != 0)
+ if (error_value != 0)
printk(KERN_WARNING "cciss: cmd %p has CHECK CONDITION"
" sense key = 0x%x\n", cmd, sense_key);
- return error_count;
+ return error_value;
}

/* SG_IO or similar, copy sense data back */
@@ -2401,7 +2428,7 @@ static inline int evaluate_target_status
} else
cmd->rq->sense_len = 0;

- return error_count;
+ return error_value;
}

/* checks the status of the job and calls complete buffers to mark all
@@ -2417,7 +2444,7 @@ static inline void complete_command(ctlr
rq->errors = 0;

if (timeout)
- rq->errors = 1;
+ rq->errors = make_status_bytes(0, 0, 0, DRIVER_TIMEOUT);

if (cmd->err_info->CommandStatus == 0) /* no error has occurred */
goto after_error_processing;
@@ -2443,32 +2470,44 @@ static inline void complete_command(ctlr
case CMD_INVALID:
printk(KERN_WARNING "cciss: cmd %p is "
"reported invalid\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
case CMD_PROTOCOL_ERR:
printk(KERN_WARNING "cciss: cmd %p has "
"protocol error \n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
case CMD_HARDWARE_ERR:
printk(KERN_WARNING "cciss: cmd %p had "
" hardware error\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
case CMD_CONNECTION_LOST:
printk(KERN_WARNING "cciss: cmd %p had "
"connection lost\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
case CMD_ABORTED:
printk(KERN_WARNING "cciss: cmd %p was "
"aborted\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ABORT);
break;
case CMD_ABORT_FAILED:
printk(KERN_WARNING "cciss: cmd %p reports "
"abort failed\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
case CMD_UNSOLICITED_ABORT:
printk(KERN_WARNING "cciss%d: unsolicited "
@@ -2482,17 +2521,23 @@ static inline void complete_command(ctlr
printk(KERN_WARNING
"cciss%d: %p retried too "
"many times\n", h->ctlr, cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ABORT);
break;
case CMD_TIMEOUT:
printk(KERN_WARNING "cciss: cmd %p timedout\n", cmd);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
break;
default:
printk(KERN_WARNING "cciss: cmd %p returned "
"unknown status %x\n", cmd,
cmd->err_info->CommandStatus);
- rq->errors = 1;
+ rq->errors = make_status_bytes(SAM_STAT_GOOD,
+ cmd->err_info->CommandStatus, DRIVER_OK,
+ blk_pc_request(cmd->rq) ? DID_PASSTHROUGH : DID_ERROR);
}

after_error_processing:
_

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Next message: Andrew Morton: "Re: [PATCH 5/20] Introduce struct upid"
Previous message: Linas Vepstas: "Re: [PATCH] [459/2many] MAINTAINERS - SPIDERNET NETWORK DRIVER for CELL"
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