* [PATCH] Try #2: Use SCSI read/write(16) with >2TB drives
[not found] <50A2F12F.9060209 () redhat ! com>
@ 2012-11-14 5:55 ` Jason J. Herne
2012-11-14 19:02 ` Sebastian Andrzej Siewior
0 siblings, 1 reply; 3+ messages in thread
From: Jason J. Herne @ 2012-11-14 5:55 UTC (permalink / raw)
To: linux-scsi; +Cc: linux-usb, pbonzini, JBottomley, stern, Jason J. Herne
From: "Jason J. Herne" <hernejj@gmail.com>
Force large capacity (> 2TB) drives to use READ/WRITE(16) instead of
READ/WRITE(10). Some(most/all?) USB enclosures do not like READ(10) commands
when a large capacity drive is installed.
Signed-off-by: Jason J. Herne <hernejj@gmail.com>
---
drivers/scsi/sd.c | 5 ++++-
include/scsi/scsi_device.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 12f6fdf..9611d6b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -887,7 +887,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
- } else if (block > 0xffffffff) {
+ } else if (sdp->use_16_for_rw) {
SCpnt->cmnd[0] += READ_16 - READ_6;
SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);
SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
@@ -2054,6 +2054,9 @@ got_data:
}
}
+ /* Use read/write(16) for > 2TB disks */
+ sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);
+
/* Rescale capacity to 512-byte units */
if (sector_size == 4096)
sdkp->capacity <<= 3;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 88fae8d..19ab8f1 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -135,6 +135,7 @@ struct scsi_device {
* because we did a bus reset. */
unsigned use_10_for_rw:1; /* first try 10-byte read / write */
unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
+ unsigned use_16_for_rw:1; /* Use read/write(16) over read/write(10) */
unsigned skip_ms_page_8:1; /* do not use MODE SENSE page 0x08 */
unsigned skip_ms_page_3f:1; /* do not use MODE SENSE page 0x3f */
unsigned skip_vpd_pages:1; /* do not read VPD pages */
--
1.7.9.5
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Try #2: Use SCSI read/write(16) with >2TB drives
2012-11-14 5:55 ` [PATCH] Try #2: Use SCSI read/write(16) with >2TB drives Jason J. Herne
@ 2012-11-14 19:02 ` Sebastian Andrzej Siewior
2012-11-14 22:06 ` Jason J. Herne
0 siblings, 1 reply; 3+ messages in thread
From: Sebastian Andrzej Siewior @ 2012-11-14 19:02 UTC (permalink / raw)
To: Jason J. Herne; +Cc: linux-scsi, linux-usb, pbonzini, JBottomley, stern
On Wed, Nov 14, 2012 at 12:55:13AM -0500, Jason J. Herne wrote:
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -887,7 +887,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
> SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
> SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
> SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
> - } else if (block > 0xffffffff) {
> + } else if (sdp->use_16_for_rw) {
> SCpnt->cmnd[0] += READ_16 - READ_6;
> SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);
> SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
> @@ -2054,6 +2054,9 @@ got_data:
> }
> }
>
> + /* Use read/write(16) for > 2TB disks */
> + sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);
The comment is pointless if you assume the reading is able to read C. What
would help is a link either here or in patch's description to the mail thread
where it has been descovered that some >2TB devices don't recognize the small
command.
> +
> /* Rescale capacity to 512-byte units */
> if (sector_size == 4096)
> sdkp->capacity <<= 3;
Sebastian
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Try #2: Use SCSI read/write(16) with >2TB drives
2012-11-14 19:02 ` Sebastian Andrzej Siewior
@ 2012-11-14 22:06 ` Jason J. Herne
0 siblings, 0 replies; 3+ messages in thread
From: Jason J. Herne @ 2012-11-14 22:06 UTC (permalink / raw)
To: Sebastian Andrzej Siewior
Cc: linux-scsi, linux-usb, Paolo Bonzini, JBottomley, Alan Stern
On Wed, Nov 14, 2012 at 2:02 PM, Sebastian Andrzej Siewior
<sebastian@breakpoint.cc> wrote:
> On Wed, Nov 14, 2012 at 12:55:13AM -0500, Jason J. Herne wrote:
>> }
>> }
>>
>> + /* Use read/write(16) for > 2TB disks */
>> + sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);
>
> The comment is pointless if you assume the reading is able to read C. What
> would help is a link either here or in patch's description to the mail thread
> where it has been descovered that some >2TB devices don't recognize the small
> command.
I've removed the comment entirely and added a link to the original
post within the patch
description. Resending in separate e-mail.
--
- Jason J. Herne (hernejj@gmail.com)
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-11-14 22:06 UTC | newest]
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[not found] <50A2F12F.9060209 () redhat ! com>
2012-11-14 5:55 ` [PATCH] Try #2: Use SCSI read/write(16) with >2TB drives Jason J. Herne
2012-11-14 19:02 ` Sebastian Andrzej Siewior
2012-11-14 22:06 ` Jason J. Herne
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