PROBLEM: 2.6.3 hangs when writing to scsi-dvd
Joachim Feise
> [1.] One line summary of the problem:
> 2.6.3 hangs when writing to scsi-dvd
>
> [2.] Full description of the problem/report:
>
> I have a DVD drive (BTC1004) connected via an IDE-SCSI bridge to
> an Adaptec 29160 host adapter.
> With kernel 2.6.3, I experience a complete system hang whenever I try
> to record data on a DVD.
> It requires a reboot.
More info:
on the cdwrite list, somebody reported a similar problem
(http://lists.debian.org/cdwrite/2004/cdwrite-200402/msg00081.html)
His quick-n-dirty fix works for me:
--- linux-2.6.3/drivers/scsi/scsi_lib.c.orig 2004-02-17 19:57:57.000000000 -0800
+++ linux-2.6.3/drivers/scsi/scsi_lib.c 2004-02-20 13:52:46.000000000 -0800
@@ -1292,7 +1292,7 @@
* host adapters. A host driver can alter this mask in its
* slave_alloc() or slave_configure() callback if necessary.
*/
- blk_queue_dma_alignment(q, (8 - 1));
+ /* blk_queue_dma_alignment(q, (8 - 1)); */
if (!shost->use_clustering)
clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
But without knowing what this particular line does, it is impossible for me
to say if commenting out the line is the right thing to do.
-Joe
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Michael Guntsche
> More info:
> on the cdwrite list, somebody reported a similar problem
> (http://lists.debian.org/cdwrite/2004/cdwrite-200402/msg00081.html)
That was me.
Since this now really looks like a kernel related problem I post to this
list.
Looking through the code of growisofs (part of dvd+rw-tools) I noticed
that it only hangs if it calls an SG_IO ioctl with a datalen of 8 or
multiple value (16,24).
There it freezes and I see the following error
Feb 21 10:44:14 roadrunner kernel: Current sr0: sense = 70 4
Feb 21 10:44:14 roadrunner kernel: ASC=1b ASCQ= 0
Feb 21 10:44:14 roadrunner kernel: Raw sense data:0x70 0x00 0x04 0x00
0x00 0x00 0x00 0x0a 0x00 0x00 0x00 0x00 0x1b 0x00 0x00 0x00 0x00 0x00
Feb 21 10:44:23 roadrunner kernel: SCSI error : <0 0 0 0> return code =
0x8000002
If I increase the buflen by 1 if it is (8,16,24) the ioctl returns and
everything works.
Since my knowledge about the SCSI internals is pretty limited Im pretty
sure that this isn't the right fix.
As stated in my mail to the cdwrite-ml removing the dma alignment to 8 byte works too.
This happens with an external DVD-Writer connected via firewire.
Could someone take a look at it and help me please?
Thanks in advance,
Michael
Kai Makisara
from the various messages related to probably one problem to get all of us
on the same track. Jens is included because he might directly see a
solution.
On Fri, 20 Feb 2004, Joachim Feise wrote:
> Joachim Feise wrote on 2/19/2004 11:47:
>
> > [1.] One line summary of the problem:
> > 2.6.3 hangs when writing to scsi-dvd
> >
> > [2.] Full description of the problem/report:
> >
> > I have a DVD drive (BTC1004) connected via an IDE-SCSI bridge to
> > an Adaptec 29160 host adapter.
> > With kernel 2.6.3, I experience a complete system hang whenever I try
> > to record data on a DVD.
> > It requires a reboot.
>
> More info:
> on the cdwrite list, somebody reported a similar problem
> (http://lists.debian.org/cdwrite/2004/cdwrite-200402/msg00081.html)
>
> His quick-n-dirty fix works for me:
>
> --- linux-2.6.3/drivers/scsi/scsi_lib.c.orig 2004-02-17 19:57:57.000000000 -0800
> +++ linux-2.6.3/drivers/scsi/scsi_lib.c 2004-02-20 13:52:46.000000000 -0800
> @@ -1292,7 +1292,7 @@
> * host adapters. A host driver can alter this mask in its
> * slave_alloc() or slave_configure() callback if necessary.
> */
> - blk_queue_dma_alignment(q, (8 - 1));
> + /* blk_queue_dma_alignment(q, (8 - 1)); */
>
> if (!shost->use_clustering)
> clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
>
> But without knowing what this particular line does, it is impossible for me
> to say if commenting out the line is the right thing to do.
>
This line has has several duties. For me, it sets the alignment constaint
used by st for deciding whether to use direct i/o or internal buffer. For
other people more important is that it is used for similar purpose in
linux/fs/bio.c. The beginning of __bio_map_user contains the following:
/*
* transfer and buffer must be aligned to at least hardsector
* size for now, in the future we can relax this restriction
*/
if ((uaddr & queue_dma_alignment(q)) || (len & queue_dma_alignment(q)))
return NULL;
Without the call to blk_queue_alignment() in scsi_lib.c, the queue
alignment is to 512 byte boundary and the transfer size must be a multiple
of 512 bytes. With the calls, the unit is 8 bytes.
The function sg_io in linux/drivers/scsi/scsi_ioctl.c contains this:
/*
* first try to map it into a bio. reading from device will
* be a write to vm.
*/
bio = bio_map_user(q, NULL, (unsigned long) hdr->dxferp,
hdr->dxfer_len, reading);
/*
* if bio setup failed, fall back to slow approach
*/
if (!bio) {
bio_map_user() calls __bio_map_user() and so the previous conditions are
used in sg_io() to decide on bouncing.
I made a test program that uses sg_io() to send a command to a SCSI
device. I tested it with a SCSI tape device. Without any changes the
program hung. The SCSI driver was sym53c8xx_2 and it loops on the
following error:
Feb 23 13:24:17 box kernel: sym1:5:0:extraneous data discarded.
Feb 23 13:24:17 box kernel: sym1:5:0:COMMAND FAILED (87 0 1).
Feb 23 13:24:17 box kernel: SCSI error : <1 0 5 0> return code = 0x70000
The I modified the program to align the buffer to 512 byte boundary. This
did not help. The next step was to set the transfer size to 512 bytes.
This helps!! Restoring the non-512 byte alignment did not cause any
problems.
The conclusion at this phase is that _the tranfer length in bio must be a
multiple of 512 bytes_.
I hope someone sees no where the real problem is.
--
Kai
Jens Axboe
SCSI io completion path (sr/sd/st rw_intr() -> scsi_io_completion() ->
scsi_end_request()) doesn't properly handle non-sector aligned data
transfers. This patch should fix it up. Warning: untested.
===== drivers/scsi/scsi_lib.c 1.118 vs edited =====
--- 1.118/drivers/scsi/scsi_lib.c Mon Feb 2 17:14:22 2004
+++ edited/drivers/scsi/scsi_lib.c Mon Feb 23 14:21:36 2004
@@ -493,7 +493,7 @@
* at some point during this call.
*/
static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
- int sectors, int requeue)
+ int bytes, int requeue)
{
request_queue_t *q = cmd->device->request_queue;
struct request *req = cmd->request;
@@ -503,12 +503,15 @@
* If there are blocks left over at the end, set up the command
* to queue the remainder of them.
*/
- if (end_that_request_first(req, uptodate, sectors)) {
- int leftover = req->hard_nr_sectors - sectors;
+ if (end_that_request_chunk(req, uptodate, bytes)) {
+ int leftover = (req->hard_nr_sectors << 9) - bytes;
+
+ if (blk_pc_request(req))
+ leftover = req->data_len - bytes;
/* kill remainder if no retrys */
if (!uptodate && blk_noretry_request(req))
- end_that_request_first(req, 0, leftover);
+ end_that_request_chunk(req, 0, leftover);
else {
if (requeue)
/*
@@ -649,11 +652,11 @@
* b) We can just use scsi_requeue_command() here. This would
* be used if we just wanted to retry, for example.
*/
-void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
- int block_sectors)
+void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes,
+ unsigned int block_bytes)
{
int result = cmd->result;
- int this_count = cmd->bufflen >> 9;
+ int this_count = cmd->bufflen;
request_queue_t *q = cmd->device->request_queue;
struct request *req = cmd->request;
int clear_errors = 1;
@@ -705,9 +708,9 @@
* Next deal with any sectors which we were able to correctly
* handle.
*/
- if (good_sectors >= 0) {
- SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d sectors done.\n",
- req->nr_sectors, good_sectors));
+ if (good_bytes >= 0) {
+ SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n",
+ req->nr_sectors, good_bytes));
SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
if (clear_errors)
@@ -717,13 +720,13 @@
* they will have been finished off by the first command.
* If not, then we have a multi-buffer command.
*
- * If block_sectors != 0, it means we had a medium error
+ * If block_bytes != 0, it means we had a medium error
* of some sort, and that we want to mark some number of
* sectors as not uptodate. Thus we want to inhibit
* requeueing right here - we will requeue down below
* when we handle the bad sectors.
*/
- cmd = scsi_end_request(cmd, 1, good_sectors, result == 0);
+ cmd = scsi_end_request(cmd, 1, good_bytes, result == 0);
/*
* If the command completed without error, then either finish off the
@@ -808,7 +811,7 @@
(int) cmd->device->id, (int) cmd->device->lun);
print_command(cmd->data_cmnd);
print_sense("", cmd);
- cmd = scsi_end_request(cmd, 0, block_sectors, 1);
+ cmd = scsi_end_request(cmd, 0, block_bytes, 1);
return;
default:
break;
@@ -837,8 +840,10 @@
* We sometimes get this cruft in the event that a medium error
* isn't properly reported.
*/
- cmd = scsi_end_request(cmd, 0, req->current_nr_sectors, 1);
- return;
+ block_bytes = req->hard_cur_sectors << 9;
+ if (!block_bytes)
+ block_bytes = req->data_len;
+ cmd = scsi_end_request(cmd, 0, block_bytes, 1);
}
}
===== drivers/scsi/sd.c 1.140 vs edited =====
--- 1.140/drivers/scsi/sd.c Wed Feb 4 20:20:06 2004
+++ edited/drivers/scsi/sd.c Mon Feb 23 14:10:00 2004
@@ -661,8 +661,8 @@
static void sd_rw_intr(struct scsi_cmnd * SCpnt)
{
int result = SCpnt->result;
- int this_count = SCpnt->bufflen >> 9;
- int good_sectors = (result == 0 ? this_count : 0);
+ int this_count = SCpnt->bufflen;
+ int good_bytes = (result == 0 ? this_count : 0);
sector_t block_sectors = 1;
sector_t error_sector;
#ifdef CONFIG_SCSI_LOGGING
@@ -688,6 +688,8 @@
case MEDIUM_ERROR:
if (!(SCpnt->sense_buffer[0] & 0x80))
break;
+ if (!blk_fs_request(SCpnt->request))
+ break;
error_sector = (SCpnt->sense_buffer[3] << 24) |
(SCpnt->sense_buffer[4] << 16) |
(SCpnt->sense_buffer[5] << 8) |
@@ -718,9 +720,9 @@
}
error_sector &= ~(block_sectors - 1);
- good_sectors = error_sector - SCpnt->request->sector;
- if (good_sectors < 0 || good_sectors >= this_count)
- good_sectors = 0;
+ good_bytes = (error_sector - SCpnt->request->sector) << 9;
+ if (good_bytes < 0 || good_bytes >= this_count)
+ good_bytes = 0;
break;
case RECOVERED_ERROR:
@@ -732,7 +734,7 @@
print_sense("sd", SCpnt);
SCpnt->result = 0;
SCpnt->sense_buffer[0] = 0x0;
- good_sectors = this_count;
+ good_bytes = this_count;
break;
case ILLEGAL_REQUEST:
@@ -755,7 +757,7 @@
* how many actual sectors finished, and how many sectors we need
* to say have failed.
*/
- scsi_io_completion(SCpnt, good_sectors, block_sectors);
+ scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
}
static int media_not_present(struct scsi_disk *sdkp, struct scsi_request *srp)
===== drivers/scsi/sr.c 1.98 vs edited =====
--- 1.98/drivers/scsi/sr.c Mon Feb 9 21:59:10 2004
+++ edited/drivers/scsi/sr.c Mon Feb 23 14:20:57 2004
@@ -179,14 +179,14 @@
static void rw_intr(struct scsi_cmnd * SCpnt)
{
int result = SCpnt->result;
- int this_count = SCpnt->bufflen >> 9;
- int good_sectors = (result == 0 ? this_count : 0);
+ int this_count = SCpnt->bufflen;
+ int good_bytes = (result == 0 ? this_count : 0);
int block_sectors = 0;
long error_sector;
struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
#ifdef DEBUG
- printk("sr.c done: %x %p\n", result, SCpnt->request->bh->b_data);
+ printk("sr.c done: %x\n", result);
#endif
/*
@@ -203,6 +203,8 @@
case ILLEGAL_REQUEST:
if (!(SCpnt->sense_buffer[0] & 0x90))
break;
+ if (!blk_fs_request(SCpnt->request))
+ break;
error_sector = (SCpnt->sense_buffer[3] << 24) |
(SCpnt->sense_buffer[4] << 16) |
(SCpnt->sense_buffer[5] << 8) |
@@ -215,9 +217,9 @@
if (cd->device->sector_size == 2048)
error_sector <<= 2;
error_sector &= ~(block_sectors - 1);
- good_sectors = error_sector - SCpnt->request->sector;
- if (good_sectors < 0 || good_sectors >= this_count)
- good_sectors = 0;
+ good_bytes = (error_sector - SCpnt->request->sector) << 9;
+ if (good_bytes < 0 || good_bytes >= this_count)
+ good_bytes = 0;
/*
* The SCSI specification allows for the value
* returned by READ CAPACITY to be up to 75 2K
@@ -241,7 +243,7 @@
print_sense("sr", SCpnt);
SCpnt->result = 0;
SCpnt->sense_buffer[0] = 0x0;
- good_sectors = this_count;
+ good_bytes = this_count;
break;
default:
@@ -254,7 +256,7 @@
* how many actual sectors finished, and how many sectors we need
* to say have failed.
*/
- scsi_io_completion(SCpnt, good_sectors, block_sectors);
+ scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
}
static int sr_init_command(struct scsi_cmnd * SCpnt)
===== drivers/scsi/st.c 1.77 vs edited =====
--- 1.77/drivers/scsi/st.c Fri Feb 6 09:21:37 2004
+++ edited/drivers/scsi/st.c Mon Feb 23 14:23:46 2004
@@ -4011,7 +4011,7 @@
static void st_intr(struct scsi_cmnd *SCpnt)
{
- scsi_io_completion(SCpnt, (SCpnt->result ? 0: SCpnt->bufflen >> 9), 1);
+ scsi_io_completion(SCpnt, (SCpnt->result ? 0: SCpnt->bufflen), 1);
}
/*
===== include/scsi/scsi_cmnd.h 1.3 vs edited =====
--- 1.3/include/scsi/scsi_cmnd.h Sat Sep 20 11:36:20 2003
+++ edited/include/scsi/scsi_cmnd.h Mon Feb 23 14:21:27 2004
@@ -158,6 +158,6 @@
extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, int);
extern void scsi_put_command(struct scsi_cmnd *);
-extern void scsi_io_completion(struct scsi_cmnd *, int, int);
+extern void scsi_io_completion(struct scsi_cmnd *, unsigned int, unsigned int);
#endif /* _SCSI_SCSI_CMND_H */
--
Jens Axboe
mi...@it-loops.com
>> --- linux-2.6.3/drivers/scsi/scsi_lib.c.orig 2004-02-17 19:57:57.000000000 -0800
>> +++ linux-2.6.3/drivers/scsi/scsi_lib.c 2004-02-20 13:52:46.000000000 -0800
>> @@ -1292,7 +1292,7 @@
>> * host adapters. A host driver can alter this mask in its
>> * slave_alloc() or slave_configure() callback if necessary.
>> */
>> - blk_queue_dma_alignment(q, (8 - 1));
>> + /* blk_queue_dma_alignment(q, (8 - 1)); */
>>
>> if (!shost->use_clustering)
>> clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
>>
>> But without knowing what this particular line does, it is impossible for me
>> to say if commenting out the line is the right thing to do.
>>
> This line has has several duties. For me, it sets the alignment constaint
> used by st for deciding whether to use direct i/o or internal buffer. For
> other people more important is that it is used for similar purpose in
> linux/fs/bio.c. The beginning of __bio_map_user contains the following:
<snip>
Thanks for the info. Since my problem occured with an external firewire
burner I asked Ben Collins (maintainer of the sbp2 driver) about it this
weekend.
The USB2 port of the burner worked without any problems, so we took a look
at the USB mass-storage driver.
It calls blk_queue_dma_alignment(q, (512 - 1)) in slave_configure.
We decided to add a slave_configure in sbp2 too and it works now.
I know that this doesn't solve the problem for other users, but it seems to
be the fastest solution for devices connected via sbp2.
Michael
Jens Axboe
>
> > On Mon, Feb 23 2004, Kai Makisara wrote:
> > > I hope someone sees no where the real problem is.
> >
> > SCSI io completion path (sr/sd/st rw_intr() -> scsi_io_completion() ->
> > scsi_end_request()) doesn't properly handle non-sector aligned data
> > transfers. This patch should fix it up. Warning: untested.
> >
> the program only does an inquiry, I tried it with the SCSI system disk
> without problems. Unfortunately, I don't have access to a SCSI CDROM now.
Great, that's promising (code like this tends to either break at first
access, or work :-). Thanks for testing.
--
Jens Axboe
Kai Makisara
> On Mon, Feb 23 2004, Kai Makisara wrote:
...
> > I hope someone sees no where the real problem is.
>
> SCSI io completion path (sr/sd/st rw_intr() -> scsi_io_completion() ->
> scsi_end_request()) doesn't properly handle non-sector aligned data
> transfers. This patch should fix it up. Warning: untested.
>
Now it is slightly tested: it works with my SCSI tape test program. Since
the program only does an inquiry, I tried it with the SCSI system disk
without problems. Unfortunately, I don't have access to a SCSI CDROM now.
--
Kai
Frank Pieczynski
> > > > I hope someone sees no where the real problem is.
> > >
> > > SCSI io completion path (sr/sd/st rw_intr() -> scsi_io_completion() ->
> > > scsi_end_request()) doesn't properly handle non-sector aligned data
> > > transfers. This patch should fix it up. Warning: untested.
> >
> > Now it is slightly tested: it works with my SCSI tape test program. Since
> > the program only does an inquiry, I tried it with the SCSI system disk
> > without problems. Unfortunately, I don't have access to a SCSI CDROM now.
>
> access, or work :-). Thanks for testing.
Hello all,
yes, this fix works! I can open k3b now without problems.
And yes, my other SCSI devices are still working, also my SATA disks using
libata.
Thank you ver much,
Frank