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[SCSI] sd: Try READ CAPACITY 16 first for SBC-2 devices

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New features are being added to the READ CAPACITY 16 results, so we
want to issue it in preference to READ CAPACITY 10.  Unfortunately, some
devices misbehave when they see a READ CAPACITY 16, so we restrict this
command to devices which claim conformance to SPC-3 (aka SBC-2), or claim
they have features which are only reported in the READ CAPACITY 16 data.

The READ CAPACITY 16 command is optional, even for SBC-2 devices, so
we fall back to READ CAPACITY 10 if READ CAPACITY 16 fails.

[jejb: don't error if device supports SBC-2 but doesn't support RC16]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Matthew Wilcox 2009-03-12 14:20:30 -04:00 committed by James Bottomley
parent 0da205e01b
commit 2b301307f6
1 changed files with 24 additions and 3 deletions
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27
drivers/scsi/sd.c
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@ -1329,8 +1329,17 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
if (media_not_present(sdkp, &sshdr))
return -ENODEV;
if (the_result)
if (the_result) {
sense_valid = scsi_sense_valid(&sshdr);
if (sense_valid &&
sshdr.sense_key == ILLEGAL_REQUEST &&
(sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
sshdr.ascq == 0x00)
/* Invalid Command Operation Code or
* Invalid Field in CDB, just retry
* silently with RC10 */
return -EINVAL;
}
retries--;
} while (the_result && retries);
@ -1414,6 +1423,15 @@ static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
return sector_size;
}
static int sd_try_rc16_first(struct scsi_device *sdp)
{
if (sdp->scsi_level > SCSI_SPC_2)
return 1;
if (scsi_device_protection(sdp))
return 1;
return 0;
}
/*
* read disk capacity
*/
@ -1423,11 +1441,14 @@ sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
int sector_size;
struct scsi_device *sdp = sdkp->device;
/* Force READ CAPACITY(16) when PROTECT=1 */
if (scsi_device_protection(sdp)) {
if (sd_try_rc16_first(sdp)) {
sector_size = read_capacity_16(sdkp, sdp, buffer);
if (sector_size == -EOVERFLOW)
goto got_data;
if (sector_size == -ENODEV)
return;
if (sector_size < 0)
sector_size = read_capacity_10(sdkp, sdp, buffer);
if (sector_size < 0)
return;
} else {