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Change the SCSI INQUIRY peripheral qualifier that CTL reports for LUNs

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that don't exist.

Anecdotal evidence indicates that it is better to return 011b (bad LUN)
than 001b (LUN offline).  However, this change also gives the user a
sysctl/tunable, kern.cam.ctl.inquiry_pq_no_lun, to override the change
and return to the previous behavior.  (The previous behavior was to
return 001b, or LUN offline.)

ctl.c:		Change the default inquiry peripheral qualifier to 011b,
		and add a sysctl and tunable to allow the user to change
		it back to 001b if needed.

		Don't insert a Copan copyright statement in the inquiry
		data.  The copyright statements on the files are
		sufficient.

ctl_private.h:	Add sysctl variable context to the CTL softc.

ctl_cmd_table.c,
ctl_frontend_internal.c,
ctl_frontend.c,
ctl_backend.c,
ctl_error.c:	Include sys/sysctl.h.

MFC after:	3 days
This commit is contained in:
ken 2012-04-06 22:23:13 +00:00
parent ea2a8fbda5
commit f5030474fb
7 changed files with 84 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
sys/cam/ctl/ctl.c
View File

@ -959,6 +959,33 @@ ctl_init(void)
softc->dev->si_drv1 = softc;
/*
* By default, return a "bad LUN" peripheral qualifier for unknown
* LUNs. The user can override this default using the tunable or
* sysctl. See the comment in ctl_inquiry_std() for more details.
*/
softc->inquiry_pq_no_lun = 1;
TUNABLE_INT_FETCH("kern.cam.ctl.inquiry_pq_no_lun",
&softc->inquiry_pq_no_lun);
sysctl_ctx_init(&softc->sysctl_ctx);
softc->sysctl_tree = SYSCTL_ADD_NODE(&softc->sysctl_ctx,
SYSCTL_STATIC_CHILDREN(_kern_cam), OID_AUTO, "ctl",
CTLFLAG_RD, 0, "CAM Target Layer");
if (softc->sysctl_tree == NULL) {
printf("%s: unable to allocate sysctl tree\n", __func__);
destroy_dev(softc->dev);
free(control_softc, M_DEVBUF);
control_softc = NULL;
return;
}
SYSCTL_ADD_INT(&softc->sysctl_ctx,
SYSCTL_CHILDREN(softc->sysctl_tree), OID_AUTO,
"inquiry_pq_no_lun", CTLFLAG_RW,
&softc->inquiry_pq_no_lun, 0,
"Report no lun possible for invalid LUNs");
mtx_init(&softc->ctl_lock, "CTL mutex", NULL, MTX_DEF);
softc->open_count = 0;
@ -1150,6 +1177,11 @@ ctl_shutdown(void)
destroy_dev(softc->dev);
sysctl_ctx_free(&softc->sysctl_ctx);
free(control_softc, M_DEVBUF);
control_softc = NULL;
printf("ctl: CAM Target Layer unloaded\n");
}
@ -9369,15 +9401,55 @@ ctl_inquiry_std(struct ctl_scsiio *ctsio)
memset(inq_ptr, 0, sizeof(*inq_ptr));
/*
* The control device is always connected. The disk device, on the
* other hand, may not be online all the time. If we don't have a
* LUN mapping, we'll just say it's offline.
* If we have a LUN configured, report it as connected. Otherwise,
* report that it is offline or no device is supported, depending
* on the value of inquiry_pq_no_lun.
*
* According to the spec (SPC-4 r34), the peripheral qualifier
* SID_QUAL_LU_OFFLINE (001b) is used in the following scenario:
*
* "A peripheral device having the specified peripheral device type
* is not connected to this logical unit. However, the device
* server is capable of supporting the specified peripheral device
* type on this logical unit."
*
* According to the same spec, the peripheral qualifier
* SID_QUAL_BAD_LU (011b) is used in this scenario:
*
* "The device server is not capable of supporting a peripheral
* device on this logical unit. For this peripheral qualifier the
* peripheral device type shall be set to 1Fh. All other peripheral
* device type values are reserved for this peripheral qualifier."
*
* Given the text, it would seem that we probably want to report that
* the LUN is offline here. There is no LUN connected, but we can
* support a LUN at the given LUN number.
*
* In the real world, though, it sounds like things are a little
* different:
*
* - Linux, when presented with a LUN with the offline peripheral
* qualifier, will create an sg driver instance for it. So when
* you attach it to CTL, you wind up with a ton of sg driver
* instances. (One for every LUN that Linux bothered to probe.)
* Linux does this despite the fact that it issues a REPORT LUNs
* to LUN 0 to get the inventory of supported LUNs.
*
* - There is other anecdotal evidence (from Emulex folks) about
* arrays that use the offline peripheral qualifier for LUNs that
* are on the "passive" path in an active/passive array.
*
* So the solution is provide a hopefully reasonable default
* (return bad/no LUN) and allow the user to change the behavior
* with a tunable/sysctl variable.
*/
if (lun != NULL)
inq_ptr->device = (SID_QUAL_LU_CONNECTED << 5) |
lun->be_lun->lun_type;
else
else if (ctl_softc->inquiry_pq_no_lun == 0)
inq_ptr->device = (SID_QUAL_LU_OFFLINE << 5) | T_DIRECT;
else
inq_ptr->device = (SID_QUAL_BAD_LU << 5) | T_NODEVICE;
/* RMB in byte 2 is 0 */
inq_ptr->version = SCSI_REV_SPC3;
@ -9491,8 +9563,6 @@ ctl_inquiry_std(struct ctl_scsiio *ctsio)
break;
}
}
sprintf((char *)inq_ptr->vendor_specific1, "Copyright (C) 2004, COPAN "
"Systems, Inc. All Rights Reserved.");
ctsio->scsi_status = SCSI_STATUS_OK;
if (ctsio->kern_data_len > 0) {

1
sys/cam/ctl/ctl_backend.c
View File

@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>

1
sys/cam/ctl/ctl_cmd_table.c
View File

@ -44,6 +44,7 @@
#include <sys/malloc.h>
#include <sys/condvar.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>

1
sys/cam/ctl/ctl_error.c
View File

@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
#include <sys/condvar.h>
#include <sys/stddef.h>
#include <sys/ctype.h>
#include <sys/sysctl.h>
#include <machine/stdarg.h>
#include <cam/scsi/scsi_all.h>

1
sys/cam/ctl/ctl_frontend.c
View File

@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
#include <sys/condvar.h>
#include <sys/endian.h>
#include <sys/queue.h>
#include <sys/sysctl.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>

1
sys/cam/ctl/ctl_frontend_internal.c
View File

@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$");
#include <sys/condvar.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>
#include <cam/ctl/ctl_io.h>

3
sys/cam/ctl/ctl_private.h
View File

@ -421,6 +421,9 @@ struct ctl_softc {
int num_luns;
ctl_gen_flags flags;
ctl_ha_mode ha_mode;
int inquiry_pq_no_lun;
struct sysctl_ctx_list sysctl_ctx;
struct sysctl_oid *sysctl_tree;
struct ctl_ioctl_info ioctl_info;
struct ctl_lun lun;
struct ctl_io_pool *internal_pool;