[SCSI] scsi_dh_alua: implement 'implied transition timeout'

During alua transitions, an array can return transitioning
status in response to rtpg requests.  These requests get
retried for a maximum of 60 seconds by default before timing
out.  Sometimes this timeout isn't sufficient to allow the
array to complete the transition.  T10-spc4 addresses this
under 'Report Target Port Groups' command.

This update retrieves the timeout value from the storage
array if available and retries the transitioning rtpgs
for up to the 'implied transitioning timeout' value

Signed-off-by: Rob Evers <revers@redhat.com>
Reviewed-by: Babu Moger <babu.moger@netapp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index f34a5a87af3..c6f0974b891 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -161,6 +161,8 @@ struct scsi_cmnd;
 #define MI_REPORT_PRIORITY   0x0e
 #define MI_REPORT_TIMESTAMP  0x0f
 #define MI_MANAGEMENT_PROTOCOL_IN 0x10
+/* value for MI_REPORT_TARGET_PGS ext header */
+#define MI_EXT_HDR_PARAM_FMT  0x20
 /* values for maintenance out */
 #define MO_SET_IDENTIFYING_INFORMATION 0x06
 #define MO_SET_TARGET_PGS     0x0a