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[SCSI] sd: Update WRITE SAME heuristics

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SATA drives located behind a SAS controller would incorrectly receive
WRITE SAME commands. Tweak the heuristics so that:

 - If REPORT SUPPORTED OPERATION CODES is provided we will use that to
   choose between WRITE SAME(16), WRITE SAME(10) and disabled. This also
   fixes an issue with the old code which would issue WRITE SAME(10)
   despite the command not being whitelisted in REPORT SUPPORTED
   OPERATION CODES.

 - If REPORT SUPPORTED OPERATION CODES is not provided we will fall back
   to WRITE SAME(10) unless the device has an ATA Information VPD page.
   The assumption is that a SATL which is smart enough to implement
   WRITE SAME would also provide REPORT SUPPORTED OPERATION CODES.

To facilitate the new heuristics scsi_report_opcode() has been modified
to so we can distinguish between "operation not supported" and "RSOC not
supported".

Reported-by: H. Peter Anvin <hpa@zytor.com>
Tested-by: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Martin K. Petersen
2013-06-06 22:15:55 -04:00
committed by James Bottomley
parent 5d65f91896
commit 66c28f9712
3 changed files with 37 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/scsi/scsi.c
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@@ -1070,8 +1070,8 @@ EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
* @opcode: opcode for command to look up
*
* Uses the REPORT SUPPORTED OPERATION CODES to look up the given
* opcode. Returns 0 if RSOC fails or if the command opcode is
* unsupported. Returns 1 if the device claims to support the command.
* opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
* unsupported and 1 if the device claims to support the command.
*/
int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
unsigned int len, unsigned char opcode)
@@ -1081,7 +1081,7 @@ int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
int result;
if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
return 0;
return -EINVAL;
memset(cmd, 0, 16);
cmd[0] = MAINTENANCE_IN;
@@ -1097,7 +1097,7 @@ int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
if (result && scsi_sense_valid(&sshdr) &&
sshdr.sense_key == ILLEGAL_REQUEST &&
(sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
return 0;
return -EINVAL;
if ((buffer[1] & 3) == 3) /* Command supported */
return 1;