On 01/18/2013 05:46 PM, James Bottomley wrote:
On Fri, 2013-01-18 at 11:27 -0500, Ewan D. Milne wrote:
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -241,6 +241,9 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
if (! scsi_command_normalize_sense(scmd, &sshdr))
return FAILED; /* no valid sense data */
+ if (sshdr.overflow)
+ scmd_printk(KERN_WARNING, scmd, "Sense data overflow");
+
if (scsi_sense_is_deferred(&sshdr))
return NEEDS_RETRY;
@@ -2059,14 +2062,18 @@ int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
sshdr->asc = sense_buffer[2];
if (sb_len > 3)
sshdr->ascq = sense_buffer[3];
+ if (sb_len > 4)
+ sshdr->overflow = ((sense_buffer[4] & 0x80) != 0);
if (sb_len > 7)
sshdr->additional_length = sense_buffer[7];
} else {
/*
* fixed format
*/
- if (sb_len > 2)
+ if (sb_len > 2) {
+ sshdr->overflow = ((sense_buffer[2] & 0x10) != 0);
sshdr->sense_key = (sense_buffer[2] & 0xf);
+ }
if (sb_len > 7) {
sb_len = (sb_len < (sense_buffer[7] + 8)) ?
sb_len : (sense_buffer[7] + 8);
This isn't the right way to do it: The overflow bit is a recent
introduction in SPC-4. The correct way to tell if we have an overflow
or not is to look at the additional sense length and compare it to the
allocation length; this will work for everything.
I'm not even convinced that overflow is important: for a lot of the
sense probes, we deliberately induce overflows by giving the request
sense command a short buffer. Printing a warning in scsi_check_sense
will get very noisy very fast.
And indeed I would rather prefer to have it the other way round;
we're using a fixed sense_buffer within the SCSI stack, which might
not be large enough to hold all sense data.
So I would prefer to have an indicator on whether _the internal_
sense buffer overflowed; this would even give us some valid use-case
now.
Plus we can add the sense buffer overflow bit to that if required.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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