Re: buggy scsi_register behaviour in 2.5.51

Re: buggy scsi_register behaviour in 2.5.51

[Douglas Gilbert]

[-- Attachment #1: Type: text/plain, Size: 6827 bytes --]

Willem,
Can't fix all those problems but I did notice that
idescsi_release() was missing a call to scsi_unregister().
With this patch the ide-scsi entry remains dangling in
sysfs (ide problem??) but the scsi host gets cleaned up
after rmmod.

The attachment is against lk 2.5.52 . The ide-scsi
driver in lk 2.5.52 needs cleaning up in several
areas. If no-one else wants to attack it then I
will.

Doug Gilbert


Willem Riede wrote:
 > I was investigating why I get
 >
 > Dec 14 14:50:55 fallguy kernel: Badness in kobject_register at lib/kobject.c:113
 > Dec 14 14:50:55 fallguy kernel: Call Trace:
 > Dec 14 14:50:55 fallguy kernel:  [<c01c7c88>] kobject_register+0x58/0x70
 > Dec 14 14:50:55 fallguy kernel:  [<c01db442>] bus_add_driver+0x82/0xd0
 > Dec 14 14:50:55 fallguy kernel:  [<c022bd00>] ide_drive_remove+0x0/0x30
 > Dec 14 14:50:55 fallguy kernel:  [<c022bdec>] ide_register_driver+0xbc/0xf0
 > Dec 14 14:50:55 fallguy kernel:  [<c0133f6a>] sys_init_module+0x1ba/0x1d0
 > Dec 14 14:50:55 fallguy kernel:  [<c010b643>] syscall_call+0x7/0xb
 >
 > when re-insmod-ing ide-scsi, and the "badness" is in sysfs create_dir,
 > appearently because the ide-scsi directory is not removed when ide-scsi
 > is unloaded so the create fails because it already exists.
 >
 > But that's not the only thing going wrong when repeatedly (un)loading.
 > See below for some really horrible effects:
 >
 > [root@fallguy linux-2.5.51]# insmod drivers/scsi/ide-scsi.ko
 > [root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
 > Attached devices:
 > Host: scsi0 Channel: 00 Id: 03 Lun: 00
 >   Vendor: OnStream Model: SC-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi0 Channel: 00 Id: 06 Lun: 00
 >   Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
 >   Type:   CD-ROM                           ANSI SCSI revision: 02
 > Host: scsi1 Channel: 00 Id: 00 Lun: 00
 >   Vendor: IBM      Model: DNES-318350W     Rev: SA30
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > Host: scsi1 Channel: 00 Id: 01 Lun: 00
 >   Vendor: IBM      Model: DGHS09U          Rev: 0350
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > Host: scsi3 Channel: 00 Id: 00 Lun: 00
 >   Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi3 Channel: 00 Id: 01 Lun: 00
 >   Vendor: OnStream Model: DI-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi3 Channel: 00 Id: 02 Lun: 00
 >   Vendor: OnStream Model: ADR Series       Rev: 5.05
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > [root@fallguy linux-2.5.51]# ls -l /sysfs/bus/ide/drivers/ide-scsi
 > total 0
 > [root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
 > drwxr-xr-x    2 root     root            0 Dec 15 15:54 
/sysfs/bus/ide/drivers/ide-scsi
 > [root@fallguy linux-2.5.51]# rmmod ide_scsi
 > [root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
 > drwxr-xr-x    2 root     root            0 Dec 15 15:54 
/sysfs/bus/ide/drivers/ide-scsi
 >
 >         ^^ the directory is still there ! ^^
 >
 > [root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
 > Attached devices:
 > Host: scsi0 Channel: 00 Id: 03 Lun: 00
 >   Vendor: OnStream Model: SC-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi0 Channel: 00 Id: 06 Lun: 00
 >   Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
 >   Type:   CD-ROM                           ANSI SCSI revision: 02
 > Host: scsi1 Channel: 00 Id: 00 Lun: 00
 >   Vendor: IBM      Model: DNES-318350W     Rev: SA30
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > Host: scsi1 Channel: 00 Id: 01 Lun: 00
 >   Vendor: IBM      Model: DGHS09U          Rev: 0350
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > [root@fallguy linux-2.5.51]# insmod drivers/scsi/ide-scsi.ko
 > [root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
 > drwxr-xr-x    2 root     root            0 Dec 15 15:54 
/sysfs/bus/ide/drivers/ide-scsi
 > [root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
 > Attached devices:
 > Host: scsi0 Channel: 00 Id: 03 Lun: 00
 >   Vendor: OnStream Model: SC-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi0 Channel: 00 Id: 06 Lun: 00
 >   Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
 >   Type:   CD-ROM                           ANSI SCSI revision: 02
 > Host: scsi1 Channel: 00 Id: 00 Lun: 00
 >   Vendor: IBM      Model: DNES-318350W     Rev: SA30
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > Host: scsi1 Channel: 00 Id: 01 Lun: 00
 >   Vendor: IBM      Model: DGHS09U          Rev: 0350
 >   Type:   Direct-Access                    ANSI SCSI revision: 03
 > Host: scsi3 Channel: 00 Id: 00 Lun: 00
 >   Vendor: OnStream Model: ADR Series       Rev: 5.05
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi3 Channel: 00 Id: 01 Lun: 00
 >   Vendor: OnStream Model: DI-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi3 Channel: 00 Id: 02 Lun: 00
 >   Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi4 Channel: 00 Id: 00 Lun: 00
 >   Vendor: OnStream Model: ADR Series       Rev: 5.05
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi4 Channel: 00 Id: 01 Lun: 00
 >   Vendor: OnStream Model: DI-30            Rev: 1.09
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 > Host: scsi4 Channel: 00 Id: 02 Lun: 00
 >   Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
 >   Type:   Sequential-Access                ANSI SCSI revision: 02
 >
 > ide-scsi has now been assigned both scsi3 and scsi4?? Its devices appear twice!
 >
 > Clearly not correct. I'll work on fixing this, but first I have a question.
 >
 > Reading the source (hosts.c), it appears that a host adapter will only get
 > the same number as it had before, if it has been specified in the module
 > parameter "scsihosts".
 >
 > Is it a concious design decision to not try and re-assign the same number as
 > before if an adapter not in "scsihosts" gets (un)loaded repeatedly?
 >
 > I think a fix for this would be different if I would try to reassign the
 > same number than if the intention is to keep assigning new numbers.
 >
 > Thanks for your advise. Willem Riede.
 >
 > -
 > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
 > the body of a message to majordomo@vger.kernel.org
 > More majordomo info at  http://vger.kernel.org/majordomo-info.html
 >

[-- Attachment #2: ide-scsi_2552x.diff --]
[-- Type: text/plain, Size: 252 bytes --]

--- linux/drivers/scsi/ide-scsi.c	2002-12-10 17:38:29.000000000 +1100
+++ linux/drivers/scsi/ide-scsi.c2552x	2002-12-17 13:06:39.000000000 +1100
@@ -658,6 +658,7 @@
 		if (drive)
 			DRIVER(drive)->busy--;
 	}
+	scsi_unregister(host);
 	return 0;
 }
 

Re: buggy scsi_register behaviour in 2.5.51

[Willem Riede]

On 2002.12.16 22:27 Douglas Gilbert wrote:
> Willem,
> Can't fix all those problems but I did notice that
> idescsi_release() was missing a call to scsi_unregister().
> With this patch the ide-scsi entry remains dangling in
> sysfs (ide problem??) but the scsi host gets cleaned up
> after rmmod.
> 
> The attachment is against lk 2.5.52 . The ide-scsi
> driver in lk 2.5.52 needs cleaning up in several
> areas. If no-one else wants to attack it then I
> will.
> 
Thanks Doug.

I'll also see if I can find what the remaining problems are. I'd also be
prepared do do "cleaning up" of ide-scsi -- what in your opinion needs
taking care of?

Regards, Willem Riede.

Re: buggy scsi_register behaviour in 2.5.51

[Douglas Gilbert]

Willem Riede wrote:
 > <snip/>
> 
> I'll also see if I can find what the remaining problems are. I'd also be
> prepared do do "cleaning up" of ide-scsi -- what in your opinion needs
> taking care of?

Willem,
ide-scsi in lk 2.5 ...
a) needs .eh_bus_reset_handler defined in idescsi_template
    and implemented. It probably would be a dummy unless there
    is a clean way to do an ATAPI bus (or device) reset.
b) replace .detect and .release in idescsi_template with the
    slave_alloc, slave_configure and slave_destroy interface

These are documented in Documentation/scsi/scsi_mid_low_api.txt .
If you find mistakes or the explanation is not clear then
complain to me. For an example of the use of these new
interfaces see scsi_debug.c or aic7xxx_old.c

Good to see that you have fixed the ide sysfs de-registration
problem.

Doug Gilbert

Re: buggy scsi_register behaviour in 2.5.51

[Willem Riede]

On 2002.12.18 07:14 Douglas Gilbert wrote:
> Willem,
> ide-scsi in lk 2.5 ...
> a) needs .eh_bus_reset_handler defined in idescsi_template
>     and implemented. It probably would be a dummy unless there
>     is a clean way to do an ATAPI bus (or device) reset.
> b) replace .detect and .release in idescsi_template with the
>     slave_alloc, slave_configure and slave_destroy interface
> 
And do request_sense itself as prescibed by the "new" error
handling I assume.

I'll be back with code when I have it.

Thanks, Willem Riede.

Re: buggy scsi_register behaviour in 2.5.51

[Willem Riede]

On 2002.12.18 07:14 Douglas Gilbert wrote:
> 
> These are documented in Documentation/scsi/scsi_mid_low_api.txt .
> If you find mistakes or the explanation is not clear then
> complain to me. 

Your doc doesn't define the second parameter to scsi_add_host.
Can you explain what the purpose is of the struct device *dev
and how I'm supposed to pull one out of my hat in __init?
I notice that the old style registration doesn't bother with
shost->host_gendev.

Thanks, Willem Riede.

Re: buggy scsi_register behaviour in 2.5.51

[Willem Riede]

[-- Attachment #1: Type: text/plain, Size: 467 bytes --]

On 2002.12.16 22:27 Douglas Gilbert wrote:
> Willem,
> Can't fix all those problems but I did notice that
> idescsi_release() was missing a call to scsi_unregister().
> With this patch the ide-scsi entry remains dangling in
> sysfs (ide problem??) 

Indeed. There is a call to driver_register in ide_register_driver
but no call to driver_unregister in ide_unregister_driver.

I put one in, and that takes care of it. PATCH to ide.c attached.

Regards, Willem Riede.


[-- Attachment #2: ide.patch --]
[-- Type: text/plain, Size: 279 bytes --]

--- ide.c-l2552	2002-12-09 21:45:52.000000000 -0500
+++ ide.c	2002-12-17 20:43:29.000000000 -0500
@@ -2314,6 +2314,8 @@
 {
 	ide_drive_t *drive;
 
+	driver_unregister(&driver->gen_driver);
+
 	spin_lock(&drivers_lock);
 	list_del(&driver->drivers);
 	spin_unlock(&drivers_lock);

buggy scsi_register behaviour in 2.5.51

[Willem Riede]

I was investigating why I get 

Dec 14 14:50:55 fallguy kernel: Badness in kobject_register at lib/kobject.c:113
Dec 14 14:50:55 fallguy kernel: Call Trace:
Dec 14 14:50:55 fallguy kernel:  [<c01c7c88>] kobject_register+0x58/0x70
Dec 14 14:50:55 fallguy kernel:  [<c01db442>] bus_add_driver+0x82/0xd0
Dec 14 14:50:55 fallguy kernel:  [<c022bd00>] ide_drive_remove+0x0/0x30
Dec 14 14:50:55 fallguy kernel:  [<c022bdec>] ide_register_driver+0xbc/0xf0
Dec 14 14:50:55 fallguy kernel:  [<c0133f6a>] sys_init_module+0x1ba/0x1d0
Dec 14 14:50:55 fallguy kernel:  [<c010b643>] syscall_call+0x7/0xb

when re-insmod-ing ide-scsi, and the "badness" is in sysfs create_dir, 
appearently because the ide-scsi directory is not removed when ide-scsi 
is unloaded so the create fails because it already exists.

But that's not the only thing going wrong when repeatedly (un)loading.
See below for some really horrible effects:

[root@fallguy linux-2.5.51]# insmod drivers/scsi/ide-scsi.ko
[root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
Attached devices: 
Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: OnStream Model: SC-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 06 Lun: 00
  Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: IBM      Model: DNES-318350W     Rev: SA30
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi1 Channel: 00 Id: 01 Lun: 00
  Vendor: IBM      Model: DGHS09U          Rev: 0350
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 01 Lun: 00
  Vendor: OnStream Model: DI-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 02 Lun: 00
  Vendor: OnStream Model: ADR Series       Rev: 5.05
  Type:   Sequential-Access                ANSI SCSI revision: 02
[root@fallguy linux-2.5.51]# ls -l /sysfs/bus/ide/drivers/ide-scsi
total 0
[root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
drwxr-xr-x    2 root     root            0 Dec 15 15:54 /sysfs/bus/ide/drivers/ide-scsi
[root@fallguy linux-2.5.51]# rmmod ide_scsi
[root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
drwxr-xr-x    2 root     root            0 Dec 15 15:54 /sysfs/bus/ide/drivers/ide-scsi

        ^^ the directory is still there ! ^^

[root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
Attached devices: 
Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: OnStream Model: SC-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 06 Lun: 00
  Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: IBM      Model: DNES-318350W     Rev: SA30
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi1 Channel: 00 Id: 01 Lun: 00
  Vendor: IBM      Model: DGHS09U          Rev: 0350
  Type:   Direct-Access                    ANSI SCSI revision: 03
[root@fallguy linux-2.5.51]# insmod drivers/scsi/ide-scsi.ko
[root@fallguy linux-2.5.51]# ls -ld /sysfs/bus/ide/drivers/ide-scsi
drwxr-xr-x    2 root     root            0 Dec 15 15:54 /sysfs/bus/ide/drivers/ide-scsi
[root@fallguy linux-2.5.51]# cat /proc/scsi/scsi
Attached devices: 
Host: scsi0 Channel: 00 Id: 03 Lun: 00
  Vendor: OnStream Model: SC-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 06 Lun: 00
  Vendor: MATSHITA Model: CD-R   CW-7502   Rev: 4.17
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: IBM      Model: DNES-318350W     Rev: SA30
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi1 Channel: 00 Id: 01 Lun: 00
  Vendor: IBM      Model: DGHS09U          Rev: 0350
  Type:   Direct-Access                    ANSI SCSI revision: 03
Host: scsi3 Channel: 00 Id: 00 Lun: 00
  Vendor: OnStream Model: ADR Series       Rev: 5.05
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 01 Lun: 00
  Vendor: OnStream Model: DI-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 02 Lun: 00
  Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi4 Channel: 00 Id: 00 Lun: 00
  Vendor: OnStream Model: ADR Series       Rev: 5.05
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi4 Channel: 00 Id: 01 Lun: 00
  Vendor: OnStream Model: DI-30            Rev: 1.09
  Type:   Sequential-Access                ANSI SCSI revision: 02
Host: scsi4 Channel: 00 Id: 02 Lun: 00
  Vendor: CONNER   Model: CTT8000-A        Rev: 2.08
  Type:   Sequential-Access                ANSI SCSI revision: 02

ide-scsi has now been assigned both scsi3 and scsi4?? Its devices appear twice!

Clearly not correct. I'll work on fixing this, but first I have a question.

Reading the source (hosts.c), it appears that a host adapter will only get
the same number as it had before, if it has been specified in the module
parameter "scsihosts".

Is it a concious design decision to not try and re-assign the same number as
before if an adapter not in "scsihosts" gets (un)loaded repeatedly?

I think a fix for this would be different if I would try to reassign the
same number than if the intention is to keep assigning new numbers.

Thanks for your advise. Willem Riede.