SAM advertises the use of a Well-known LUN (W_LUN) for scanning.
As this avoids exposing LUN 0 (which might be a valid LUN) for
all initiators it is the preferred method for LUN scanning on
some arrays.
So we should be using W_LUN for scanning, too. If the W_LUN is
not supported we'll fall back to use LUN 0.
For broken W_LUN implementations a new blacklist flag
'BLIST_NO_WLUN' is added.
Signed-off-by: Hannes Reinecke <h...@suse.de>
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 3e58b22..f4ccdea 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1312,6 +1312,7 @@ static int scsi_report_lun_scan(struct scsi_target
*starget, int bflags,
unsigned int num_luns;
unsigned int retries;
int result;
+ int w_lun = SCSI_W_LUN_REPORT_LUNS;
struct scsi_lun *lunp, *lun_data;
u8 *data;
struct scsi_sense_hdr sshdr;
@@ -1337,11 +1338,20 @@ static int scsi_report_lun_scan(struct scsi_target
*starget, int bflags,
return 0;
if (starget->no_report_luns)
return 1;
+ if (bflags & BLIST_NO_WLUN)
+ w_lun = 0;
+retry_report_lun_scan:
if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
- sdev = scsi_alloc_sdev(starget, 0, NULL);
- if (!sdev)
- return 0;
+ sdev = scsi_alloc_sdev(starget, w_lun, NULL);
+ if (!sdev) {
+ if (w_lun != 0) {
+ w_lun = 0;
+ sdev = scsi_alloc_sdev(starget, w_lun, NULL);
+ }
+ if (!sdev)
+ return 0;
+ }
if (scsi_device_get(sdev)) {
__scsi_remove_device(sdev);
return 0;
@@ -1418,6 +1428,18 @@ static int scsi_report_lun_scan(struct scsi_target
*starget, int bflags,
}
if (result) {
+ if (w_lun != 0 && scsi_device_created(sdev)) {
+ /*
+ * W_LUN probably not supported, try with LUN 0
+ */
+ SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan:"
+ "W_LUN not supported, try LUN 0\n"));
+ kfree(lun_data);
+ scsi_device_put(sdev);
+ __scsi_remove_device(sdev);
+ w_lun = 0;
+ goto retry_report_lun_scan;
+ }
/*
* The device probably does not support a REPORT LUN command
*/
diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
index cc1f3e7..ffb42b1 100644
--- a/include/scsi/scsi_devinfo.h
+++ b/include/scsi/scsi_devinfo.h
@@ -31,4 +31,5 @@
#define BLIST_MAX_512 0x800000 /* maximum 512 sector cdb length */
#define BLIST_ATTACH_PQ3 0x1000000 /* Scan: Attach to PQ3 devices */
#define BLIST_NO_DIF 0x2000000 /* Disable T10 PI (DIF) */
+#define BLIST_NO_WLUN 0x4000000 /* Disable W_LUN scanning */
#endif
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